Ecology and Control of the Principal Flies
Associated with a Compost Plant
CALVIN GALE ALVAREZ
A DISSERTATI'N PRESENTED TO THE GRADUATE COUNCIL OF
THE UNIVERSITY OF FLORIDA IN PARTIAL
FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF
DOCTOR OF PHILOSOPHY
UNIVERSITY OF FLORIDA
Uti,.'ERSiT OF FLORIDA
31 1262 08552 47821 1 11 1
3 1262 08552 4782
The author wishes to extend his sincere thanks and gratitude to the
many persons who have made this endeavor possible:
To Dr. F. S. Blanton and Dr. H. D. Putnam for serving as co-chairmen
of the supervisory committee, and their assistance and friendship through-
out this investigation.
To.Dr. G. C. LaBrecque for serving as a committee member, for his
assistance, direction, and friendship, and for providing equipment and
working space at the United States Department of Agriculture's Insects
Affecting Man and Animals Laboratory, Gainesville, Florida.
To Dr. J. F. Butler for his participation with the committee, for
providing equipment and working space at the Medical Entomology Laboratory,
and for his tolerance of the odors of rearing blow flies.
To Dr. D. H. Habeck for his assistance and work with the committee.
To Dr. W. G. Eden for his guidance, encouragement, and assistance.
To Dr. D. L. Bailey for providing equipment and advice.
To Dr. D. E. Weidhass and all the other members of the Insects
Affecting Man and Animals Laboratory for providing counsel and aid on
To Mr. Dan Wojcik and Mr. Terry Marable for photographic assistance.
To the Department of Environmental Engineering of the University
of Florida for financial assistance provided by Contract number 5-701-UI-
01029-09 from the United States Public Health Service.
To Mr. Herb Houston, project director of the Cainesville Municipal
Waste Conversion Authority, :r.c., and Dr. D. T. Knuth, Environrmer.:al
Engineering, Inc., for furn sh> n; eqjiT.D.-t ar.d faci i:!es as provided
by Department of Hea!lh, Educa:ion, and welfare e De-or.strat:cn Grar.t
Finally,, the author wishes to express his deepest gratitude to
his wife, Judi, for her patience and constant enccuragemert during this
TABLE OF CONTENTS
ACKNOWLEDGMENTS .................................................. i
LIST OF TABLES.................................................. vi
LIST OF FIGURES................................................ viii
Statement of the Problem............................ 3
Location of Compost Plant.......................... 4
Operation of Compost Plant......................... 5
Flies .................................... ........... 9
I. FLY LARVAL MIGRATION FROM REFUSE......................... 13
Result and Discussion .............................. 17
II. CONTROL OF BLOW FLIES.................................... 26
Blo.w Fly Traps...................................... 26
Field Tests........................................ 29
Rearing Blow Fl ies.................. ............... 37
Laboratory Screening of Insecticides for
Control of P. cuprina........................... 41
III. DENSITY AND SEASONAL FLUCTUATIONS OF HOUSE FLIES AT
THE COMPOST PLANT ...................................... 46
Rearing House Flies............... .... ..... ....... 46
Seasonal Fluctuations of House Flies............... 47
Evaluation of Fly Sticky Tapes..................... 54
Determination of the Magnitude of the House Fly
IV. HOUSE FLY BREEDING IN COMPOST............................ 60
Moisture and Age of Compost........................ 60
Sludge and Grinding. ................................ 64
Temperature ................... ..................... 67
TABLE OF CONTENTS (Continued)
V. MIGRATION AND DISPERSAL ....................... .......... 72
Literature Review ..................... ............ 72
Flight M ills....................................... 75
Bl1~ Flies Released at Compost Plant............... 78
Fly Releases at the City Landfill.................. 81
SUMMARY, CONCLUSIONS AND RECOMM;ENDATIONS....................... 100
1. Test for the precision of the counting technique used to
determine total number of larvae collected under
the apron conveyor................................. 108
2. Fly larvae trapped under apron conveyor during 1969, at
the Gainesville coTpost plant....................... 109
3. Percent mortality of 5-day old Phaenicia cuprina
females 24 hr after exposure to insecticides
in a wind tunnel .................................. Ill
4. Temperature in digesters ................................... 114
LITERATURE CITED................................................ 115
LIST OF TABLES
1. Percent abundance of species of fly larvae trapped
under apron conveyor during 1969................... 19
2. Total number of larvae collected under apron conveyor
compared to number of larvae trapped the same day.. 20
3. Total number of larvae collected per day under apron
conveyor compared to the number caught in the
same area during the night......................... 22
4. Sex, species, and abundance (%) of flies caught in
cone traps baited with I-day old fish heads
at Gainesville compost plant....................... 29
5. Number of flies caught per day in cone traps baited
with fish heads as a monitor of procedures to
control adult flies at the Gainesville compost
6. Sex, species, and abundance (%) of flies caught by
sweep net in grass adjacent to receiving area
of Gainesville compost plant........................ 34
7. Analysis of several rearing media to determine the most
suitable method of rearing Phaenicia cuprina....... 39
8. LC50 of 5-day old Phaenicia cuprina females to
insecticides in a wind tunnel ...................... 43
9. Air temperatures recorded 15 cm above compost in
digesters at Gainesville compost plant ...... ..... 51
10. Number of adult house flies caught on sticky tapes in
different ages of compost....................... ... 53
11. Recapture of 3-day old marked laboratory reared house
flies by sticky tapes hung in digesters for 24 hr
following release of flies in the same area at
the Gainesville compost plant during 1969.......... 59
LIST OF TABLES (Continued)
12. Influence of moisture and age of compost on maturation
of immature house flies reared in compost.......... 63
13. Influence of moisture on maturation of immature house
flies reared in 3-day old compost................. 65
14. Influence of sludge and grinding of refuse on maturation
of immature house flies reared in compost.......... 66
15. Temperatures observed ir house fly rearing containers.... 69
16. Temperatures observed in 4-day old compost in
17. Mean distances fla.n in 24 hr by adult Phaenicia
cuprina attached to an insect flight mill......... 79
18. Distance flaomn until death by adult Phaenicia
cuprina attached to an insect flight mill......... 80
19. Recapture of wild marked flies by sweep net and
baited traps 24 hr after release................... 82
20. Recapture of marked wild flies at Gainesville sanitary
landfill by sweep net after release............... 91
21. Observations of marked wild P. cuprina remaining at
Gainesville landfill after release............... 93
22. Observations of marked wild M. domestic remaining at
Gainesville landfill after release ................ 94
23. Average percentage of flies remaining at city landfill
under different weather conditions................. 95
24. Rainfall recorded at Gainesville Municipal Airport
during release studies at city landfill........... 96
25. Observations of 2-day old marked laboratory reared
Phaenicia cuorina remaining at Gainesville
landfill after release............................ .98
LIST CF FIGURES
1. Floor plan of Gainesville municipal caipos: plant...........
2. Refuse flao plan of Gair.esville coinpost plant............... 7
3. Receiving building filled with refuse....................... 3
4. Sorting conveyor carries refuse to sorting platform..........
5. Composting takes place in concrete digesters................ 1
6. The finished product is discharged zo outdoor storage areas. 1C
7. Fly larvae and pupae unJer receiving hopper................. 4
8. Fly larvae migrating from refuse to pupation s:tes under
wall of receiving ouild r......................... .......... 14
9. lumber of fly larvae caught under apron conveyor per
week at Gainesville compost plant during 1969....... 18
10. Eastern edge of approach ramp........... ............... .... 24
11. Fly larvae aiong base of eastern wall of approach ranp...... 24
12. Cone trap baited with 1-day old fish heads to sample
fly populations at compost plant..................... 28
13. Rear vie.- of receiving building shcx-ing receiving hopper
and pavement behind building.................... .... 23
14. tMean number of adult flies captured per sticky tape per
week during 1969, in digesters at Gainesville
compost plant....................................... 50
15. Number of house flies captured on sticky tapes within
24 hr after release in a large outdoor cage......... 56
16. Position of tia'perature process in house fl' rearir.g
LIST OF FIGURES (Continued)
17. Diagram of insect flight mill............................. 77
18. Fly larvae in animal disposal area of city landfill....... 84
19. P. cuprina roosting on grass tassel at night at city
landfill ........................................... 84
20. Predominantly 1. domestic roosting on weed at night
at city landfill................................... 85
21. Predominantly C. macellaria with some M. domestic
roosting or, dead brush in refuse at night
at city landfill................................... 85
Abstract of Dissertation Presented to the
Graduate Council of the University of Florida in Partial Fulfillment
of the Requirements for the Degree of Doctor of Philosophy
ECOLOGY AND CONTROL 0 T:HE PRINCIPAL FLIES ASSOCIATED
..'ITH A CC,-.POST PLANT
Calvin Gale Alvarez
Chairman: Dr. F. S. Elanton
Cc-chairman: Dr. H. D. Putnam
Major Department: En:ztcology and rematology
Minor Department: Environmental Engineering
Seasonal fluctuations of Diptera indigenous to domestic solid.waste
w ere examined at the Gainesville, Florida, municipal compost plant during
1968-1969. Populations of both immature and mature forms were estimated
and the efficiency of chemical and physical control procedures -.as
tested. Adult dispersal studies were conducted during 1970 at tne city
The major fly source at the compost plant was found to be from
larvae-infested incoming refuse. The greenbottle blow fly, Phaenicia
cuorina (Shannon), comprised more than 90 percent of the larvae ,-hich
migrated into protected areas where they developed into adults. Approxi-
mately 450,000 adult flies per week were produced during the summer
months. This figure could be reduced by more than 63 percent by pro-
cedural changes and good housekeeping.
The daily application of a dichlorvos sugar bait reduced the number
of flies ry Si., percent -.-:hile a s ngle applicat3or. of d:m-ct.loate reduced
t.ne population by m.or th-n 50 perccr.t: for :.ek. ara..: cn, S rba,-.,
naled, ar.d diazinon 'ere a!so .ffcct ve 4s shc.ar. by laorato.-y tests.
The number of house flies captured on sticky tapes was sho.-.n to
be proportional to the number present in a large outdoor cage. Sticky
tapes were used to sho.. seasonal fluctuations of house flies in the
House flies we.e the predcxinar.t insect breeding in cocTmpcs:. They
were l imiad to the top 2.5 cm in the digesters because of t iperature.
The optimum moisture content for hcuse fly breed:rn was 73 perc:-.:. r.c
to 14 percent of the eggs placed in ccnpost at 45-55 percent moisture
(normal operating conditions) developed ?nto pupae. Egg survival to
pupce decreased s gnificantly when placed in refuse after 5-10 days of
ccnpos t i r.g.
P. cuj.:n3 -males flea an average of 19,1.05.4 m and a maximum of
30,137 m when attached to a flight mnll until death. Fe.Tales flea. an
average of 25,235.2 m and a maximum.- of 45,030 n.
\-ild P. cuprina and Nt. comestica were marked and released I mi from
a.landfill and later recaptured at the landfill. An average of 10.17
percent of the wild P. cuDrina ar.d 1.66 percent of wild 1I. domestic
released at the landfilll on days follcaed by 24 hr without rain were
recaptured 24 hr after release. An average of 10.7 percent of the wild
P. cuorina released a: the compost plant were recaptured in the same area
24 hr later. An average of 11.3 percent of laboratory-reared P. cup.-Ina
released at the landfill %ere recaptured 24 hr later. Baited traps
surrounding the landfill recaptured only 2 flies after a total release
of 255,000 flies.
I :.T.U,, ) CT '. 3.
The de.T.ands of our affluent soc:et,, for more Socds c.nd cor.'..-.'-.
it-ms such as r.o deposit and non-rczurr.able materials, reL:'t in .f-.2
ger.rati~n of waste products in gigantic proportions. ,1s tne aff,~r.ce
and the population increase, the per capital and total amount of waste
increase proportion iy. The disposal of these tre.-nendcjs c-.z,~tiies
of wastes has primarily been an urban problem. Since the trend in the
United States "s toward urbanization the problems of refuse disposal
becar-e increasingly more important. This becomes evident when it is
noted that in 1960 the estimated median waste per capital per year in urban
areas was 1,430 pounds. This amounted to 1'80 billion pounds per year
ar.d the cost of collecting and disposing of this refuse was more than
1.5 b:llicn doi!ars (1).
To combat the rising problem of refuse disposal the "Sol id Waste
Disposal Act" was enacted in 1965 to support a national program designed
to implement and evaluate more efficient methods of coping with the
sol id waste problems. Under this act the Bureau of Solid WLaste Manage-
mer.t awarded a contract to the Gainesville -,Mnicipal Waste Conversion
Authority for the construction and operation of a refuse conpost:ng
facility. The purpose of this project was to "demonstrate the rel iabil ity,
su iab; ity', tcc.-.c.-r:c fL-s ; :it';, ar, L.L n-ita- and nu tance-rre o0.eretIon
of a rccertly Zc>ve. pi d ;',-.- tL, ;.,:J-.,.2,:c-: canpost,.s sys:ttm for ;he
d :spcsc.: cf r-.F :c'..p C fr.. .. ( ,. CI .
The primary objective cf c o costing is to dispose of refuse by
biological degradation of the organic materials. Modern scientific
cc-posting prccecures W'h;ch are emiplc'ed in municipal disposal sy'ste-:.s
involve the rap:d partial deccmnpos i;icn of orcar.ic matter by the use
of aerobic microorganisms under controlled conditions (1), municipal l
composting is a fairly conmon practice in many European countries. It
is rarely used in the United States because lard for refuse disposal was
available in close proximity to urban centers in the past. Th.
increasing demand for land provided the stimulus for municipalities
to seek a more acceptable form of refuse disposal. As late as .53,
ti.ere was little scientific information available on municipal composting
in the United States. Since then several universities and the United
States Public Health Service conducted studies that have as yet yielded
only a limited amount of practical information. The capital and operating
costs of comwposting are kno.-jn to be higher than most other forrs of
refuse disposal but the specific ecor.nnics involved in municipal co-,-
postir.g :n the United States are practically unknown. The feasibility
of co-iposting must be determined by the major advantage of c-nposting,
the recycling of waste products. The sale of marketable compost and
salvagable goods would reduce the net cost and may result in a profit.
There are 2 general composting processes that appear to be the most
efficient and economical under U.S. conditions. The first is mechanical
digestion, a process in which refuse is sorted, ground, and mechanically
manipulated in order to shorten the bioloc:cal degradation process. The
second method terr.med windrc.-.;ng involves the sorting, grinc:ng, and placing
of refuse in windrc. s allo.in; t.-.e rmateri,! to co.npost naturally. The
compost plant constructed a: Gai.-.csvile used .he mechanical .iqestion
Stte-.ent of the P:oblem
As with other scientific informationn concerning composting in the
U.S., little is knawn concerning insect problems that may arise in this
type of operation. The original purpose of the present investigation was
to search out these problems, determine their magnitude, and suggest
possible solutions. Initial observations revealed that large numbers of
fly larvae entered the compost plant within the refuse. These larvae
seeking a suitable pupation site migrated from the refuse stored in the
refuse receiving building. These insects were aesthetically unpleasant
to the employees as the larvae were often crushed beneath their shoes and
sometimes crawled into the clothing of a resting employee. Many of the
immature insects eventually became adults and further tormented the
employees at the site by their constant presence while others were reputed
to invade the surrounding community. Thus, the primary areas of this
investigation were as follows:
To identify the larvae entering the compost plant with the refuse
and to determine the:r magnitude and seasonal fluctuations.
To search out possible processing procedures which may reduce the
number of larvae migrating into the plant.
To evaluate mechanical and insecticidal control procedures to reduce
the larval populations.
To screen several commercial insecticides for their effectiveness
against the emerging adult flies.
To determine the density and seasonal fluctuations of the adult house
flies at the compost plant.
To determTine the extent and some of the l imiting factors of hcuse
fly, breeding in compost.
To deter-mine the extent of fly c;spersal froT thie coripost pl a-t
;nto the surrour.dr.i cn;To.Tir.. ty.
Laboratoory stude: s ..erc co:.dc:ed at the USDA Insects .".ffect.r.
HMn and Animals Laboratory :n CaIne;v!f e, Fligica, and at the Lnive.:L.ly
of Florida medicall Enom-nology Lcaboratory. F eld s:udeis ccncCc:cea at t.-.c
cornpos plat were begun in June, 13. becausee of a lack o fL.'.cs th .
plant was closed on DecaTmber 31, 1939, ar.d scke cf tae stLcies '..ere not
cxpar._dcd as the author had inte.-.rc, M'.ost cf .~n disperse! s-ud es wrre
aP rform.ed at the C::y of Gainesville SaniZary Lr.-.dfill durinS t'.- s.-.;er
Lc, icn of Cc-.pos: Flant
The compost plant was constructed on a 5-acre tract of land located
ir southeast Gainesville at the city's sewage treatment complex. This
size was near a se.-jage treatment plant, an animal shelter, and an
A densely populated region of midd'de-incom.e apartment complexes
inhabited primarily by Universi:y of Florida students and a la.j-incocae
residential area were located in :ne immediate vicinity. A woodland area
buffered a middle- and high-income residential area located one-half
mile from the plant.
C'oeration of CTomost Plant
The floor pl..n c. he cac.post plar.; is p.-csc..ted in Fig. I and tr.c
central flao plan o- ti, r s' .; s .-.n .-. F'.. 2. Fefuse wa. Lro r.. by
trLck andu dLmpcd or. t:.e f:cor of the -eceivir.g .l ldir.g (F:g. ;). re
refuse was then placed n:: a .-ece.:ving hopper by a actortr .o.;fi~; wj. ;
a front-end loader. The hopper ('%.8 r long, 3.6 m wide, -r. 3.i n ec,
constituted the rear side of the building. An apron conveyor which
consisted of a series of ov.erla ppr.; or inter:ockir.g r ron pans %.-s
located at the bottom of th:s hopper. Tne refuse was transported alo-.
the conveyor onto an oscu'lating taZbl. T:.;s ta2.e loosened zne packed
re.use in order to assure c. un:,or. -flo..-. A sor-:ng conveyor car.-ied
the refuse frc., the oscil.ating table to a platform where 6 labo-rrs
manually re .rved salvagemble paper, cardboard, and large bulky items
(Fig. 4). The paper and cardboard were dropped into chutes which fed
into a baler and the bulky teamss were placed in chutes that emptied into
a dump truck which carried these materials to a landfill. Tne sorted
refuse then proceeded directly into a crusher-disintegrator grinding mrill.
The ground refuse discharged froT- the crusher averaged 7.6 cm but varied
in size depending upon the type and amount of material fed into the
Refuse passed frin the first grinder into a second grinding unit which
reduced the particle size to approximately 5 cm It was then discharged
fro- the bottom of the secondary grinder into mixing screws where 2 ccunter-
roating ribbon-cype scre..s, p aced s:de by :ide in a common trough,
blended th. r..a:eria' with wte,- or sludge. A conveyor belt carri-d the
molstcned refuse unctr a rma. tic: separaoe- .- h:ch removed the ferrous
Ig.r.zr **nrloa blowr
S Illoder m /ealoadl| *bhgCrl* touvyo
giloader creeler car relle
2 I e..r ucloadln co. nyor
Lloader LrecaJr car
e r ld le.dlin convyor
a|riad drcrrlbualg ecrrw conveyor
OlrLOd mll felder ecrer coroveryors(2)
eprlod mille (2)
lalg ad ovar.loa arm roaaeyar
leariad dLschars cvarwr conveyor
Lochplilog belt coaveyor
.toraee buildLng Vorrc c loadLng ramp
.vetorl a*d *r, re
S Ilectricl evitcrner room
4TOC.L P II
Fig. 1. Floor plan of Gainesville municipal compost plant (20),
Fig. 2. Refuse flow plan of Gainesville compost plant (20).
Fig. 3. Receiving building filled with refuse.
Fig. 4. Sorting conveyor carries refuse to sorting platform.
mTiGtc.,s a...', :;".n 3=t ,-,. o.'.O t .2 ". 2C.C c,'cr.'/Gcyor D '. z o't '-h exc" de.. t
;:a.-.:h of :e d:gestrs. A s.-.ht:.e ccnvey'or, which travelled on a pal- o;
steel rails betwee. the cigeste.-s discharged the refuse into these ur..:s.
T7. disest.- s or c. gst ..g ;ar.,-.s were 2 cc.-.crete rcja, s S9 n c.-.g,
6 m wide, and 2.7 m deep (F:g. 5). The digester walls were constructed of
concrete blocks and the floor was converted with perforated gelvan:zed
stee! plates. These pat:s were above an a.r pier.um into which air was dis-
charged by a centrifLgal 1c.-i pressure fan. River gravel approximately
0.6 crm in diameter covered the perforated plates to a depth of 7-10 -n.
This enabled the air to diffuse evenly through the small slots over the
entire floor of the tank. The refuse was placed in the digesters to a
depth of 1.8-2.4 m and allowed to compost for approximately 6 days (20).
(In t.n:s investigation "crIpost" refers to refuse that has remained in
the c:gesters for a period greater than 24 hours.)
Removal of the compost was accc-.pl ished by a machine called the
Ag:-Loadc.- (Me:ro-.c;ste Patent No. 3,294,451). This machine removed the
cc-post a-.d deposited it back onto the tripper conveyor. A system, of
cc..veyor bets transported the coTnpost to a final grinding mill. A finely
ground mater;ai approximately I cm was discharged froi this grinder and
was transported by conveyor to an outdoor storage area (Fig. 6).
..ce .mot r~cmerous species o. flies prcsr.: at -:.e c-mpost pla..t were
.hu com.-.cn house fly, Miusca do-est;ca Linnaeus, (.-,scidae, Diptera) and
... r.- .'c.bott e b,. c; fly, -.-: .c cj-..' a ,S. ) (Ca phor-id
Fig. 5. Composting takes place in concrete digesters.
Fig. 6. The finished product is discharged to outdoor storage areas.
The house fly has beer. incrimin-ated as a carrier of nm.TeroLs diseases
of man and animals incl-ding typhoid fever, cholera, and amroebic dysentary
(27, 2); hc.-.ever, these cla'ns have been supported only by circunstant;:a
evidence. Hacse fly associatiu.-.s ;t;-, disas-s need farther cla-:ficatcon
as cxperimre.r:ta evidence .s sparse and con.tam.iatin of house fl s between.
caged mates has been shao.'n to o sporadic (2-).
Grcenbottle blce f! es may be cc.T.estc nuisances or carry d;seas2
organisms, but in. this coaac:ty ney are far less impc,: r.t: ..-:. other
flies. Hc..ever the damage -nd s-ffe.:r.%g which the Icr-.'ae ir.-I lc Lpo
domTestic animals in sci-e s ock<-.-a s i-o areas .s of tre.-er.dcus co.sequcr.ce.
In Australia, th:s fly is by far the rost important spe:Ies in fi st-ike
or cutaneoJs myas:s of sheep (LL:, 3). ',, strike is a condit:an pro -ced
by the development of blcw f'.l larvae on 1 giving sheep v-.hidh may lead to
death or a considerable loss of woo. This is a formidable problem in
Australia and ar.oun-s to an annual cess of 4,000,000 pounds to sheep
raisers (44, 6$).
The ccr,.on hcjse fly is well established as Musca domestic- Linnaeus
but the systematics of the greer.bottle blo.-j fly are scoTewhat confused.
Australian authors refer to this fly as Lucilia cuorina (v\.'idemann). Hall
(26) cc.mpa;-ed specimens from the United States and Australia and concluded
they were not the same species. He described the A.merican species as a
ne. ccnbinatIon, P. pallcscenes (Shannon). :.laterhouse and Paramo.ov (E0)
later examir.ed numero-s specimens fro-n Texas, Ns. York, 'New.j Orleans,
Washir.gton, and Austral ia ar.d concluded that there was no diiferenc, in
species, bjt a definite pa:r of subspL .- iJmes k2S) ccncLr:'cJ ir. ths
vie.-. .-all later in Sta.; c e al. (7c ma r.ta ,-,ec his cLm.T i ion of
on .cec-z (Sh no) r u reco, -zed the works of Watorhouse and
P -r ammv 7,0, 0u%,o T0scs the species -,z,7, from- Waterhouse and Paramonov
s ince the ir work appeared to be moa- ccr.-orchens ive than that of Hall.
SE-: .C !
FLY LARVA. MIRAT.:C:; FR.m-- REFUSE
The major source of fly infestation appeared to be from I-trodic:ir.
of larvae from. t'e coll ected refuse ar.. not :.-C m br.eca:ng at .:.e c:.,;.;:
plant Fly larvae that .4.ere breed;r.g in refcLe containers thrcj-;ic. :we
city were brought to t.e cC Ts:o p.c-at wiTh the refuse. Th;s infestedd
refuse w.;s stored z.-.'aiting process ..g in : e receiving arca. -an/ .:
the larvae were mature and the a-dc: stir..us of tr.e disruptive transfer
to the p!ant caused them to active/ seek a pupation site (F:gs.7 and 3).
Scne of these larvae migrated :nto the working areas where they' annoyed
the employees while others reached protective areas where they metamorphosed
to adults. Such occurrences v.ere not unique to the compost plant. Large
numbers of larvae may escape to pupation sites during the handling,
transferring, or processing of larvae-infested refuse. G-Cen and Kane (23)
found that 7200 larvae/hr/pcr ca. were escaping from railroad cars a-.aiting
dispatch to a rural disposal area.
The infestation of refuse bI larvae in the Gainesville area uas
anticipated because in a southern California cit, with a climate similar
to that of Gainesvile, Ecke et al. (13) reported that residential refuse
containers can h.v, zs many as C,000 .vae per cc..air,..: over a ]0-we.C
priced. These larvae crcw'.le c c. .? re s .-js c,. sh 't feed:.g period
Fig. 7. Fly larvae and pupae under receiving hopper.
Fig. 8. Fly larvae migrating from refuse to pupation sites under wall
of receiving building.
to pupate in the soil and later emerged as adults. During the hot summer
months it was reported that the feeding period was corpleted in 4 days
(79). This observation led to the recommendation and subsequent adoption
of a twice-weekly refuse collection system for several California cities
The purpose of this investigation was to determine the species of the
larvae escaping into pupation sites at the plant, to determine the
magnitude and the seasonal fluctuations of this massive influx of insects,
and to search out possible processing procedures which would reduce the
total number of escaping insects.
Visual observations indicated that the majority of the larvae escaping
from the refuse were confined to the partially enclosed area under the
apron conveyor. The larvae reached this area either by crawling through
the openings between the metal pans of the conveyor or by falling through
the opening between the floor of the receiving building and the edge of
the receiving hopper. To determine the species present and the seasonal
fluctuations of the larvae entering the plant, a trap was placed in this
area. This trap was similar in function to the described by Roth (58) and
consisted of a 30.48 cm2 plywood box.. It was abutted to the wall under
the apron conveyor so that larvae falling through the opening between the
hopper and the floor would be trapped in the box. The trap was operated
from January 12 to December 31, 1969.
The trap wa:s checked daily and the number of larvae recorded. A
minimum of one sa.-.pl, catch per week was preserved in alcohol for identi-
PorL nation Factor
It was desired that the lc.-vai population trapped in the se-scnai
fluctuation survey b. used to estimate the total number of la-vae esca?:r.c
into the plant. To accomplish, this .t was necessary t: d.termi..u. ,1
total nL.-.ber of larvae that entered the plant, the percentacg o. t-h
larvae trapped, a.d the re. iab;lity of the trapping p.ocedure.
The tot:l number of larvae enterir.g :-e plant '.;oud be c.. i:L1t
figure to accuratel'y efine. Since the majority of the larvae migrate
under the apror. co..veyor was used tc deter-:ir.e zie total number of
larvae ;n that area and to determine the reliabil;zy.
The larval population under the apron conveyor was determined by
sweepi;.g the area -or a 10-day pe.-od baginnir.c ..ug-st 29, 1909. These
sweepings, which included the debris and .arvae that had fallen during
the p.-evlcus 24 hr, were placed into a 55-gallon (208 1) drum. The drum
ar.d its contents wire weighed, sealed, and thoroughly mixed by rolling
on the floor for several minutes, l..:.ediately a volume of aporoxi.-ately
0.5 1 was removed and weighed on a laborato.-y balance (4aus, Unicn, N.J.).
Tne larvae in the sample wura counted a:,d the total number of larvae in
tne drum or under the aron conveyor was calculated.
To deterr;n.: t.-.e precision of the above method, a sample of approxi-
mately 0.5 1 was .rcmo.'J, I'e'chca, counted, ar.d replaced ir. the drum. The
ccn er .ts cf .,, w..e .ga-; n r.'.xcd' and ..a pr.ced-re wc.s re.;" icated
5 tr:.es. -. .- :..:c c t t :.-. r.ethod was precise and are ;ivtn
in Appr.dA di ..
Effects of Clearina Receiv.inq Bi;ldina Cda'i'. of Refuse
It was standard operating procedure that a sufficient a.mcunt of
refuse remain in the receiving building o.vcrnig.h so that operations
could becin the folllja ing r.crr.t.g and proceed without inte.-ruptior. L.nt:]
the trucks began de iv.erinc refuse. To deter:.r.e :r. r.-mbe. of l r.'a
escap:r.g into :ne ccTpost plant as d d;:ect re'z-;t o. t;:, proved re,
the area under the cpron co.nveyo: was swept tuice da: .y; once at 7-30 a-,
before d-l'/y op-ration: began, :nd ag z.r, at c,:5 p., iT.:ed;a '/ a:-. :.
pzant closed. This was repeated for t consecutive cays during Septer oer,
1969. The larvae co elected were er.L.merated as described previous 1y.
Result and Discuss;on
Tne resu'. s of a larval sample irg program to determine the species
present and seasonal fluctuations of the lacrvae escaping "nto the cc._.ost
plant are shown inr Fig. 9 and Appenrdix 2. These data show that relativ.Aly
fc-.' larvae were captured du.-ing Januar', Februar/, and March. The catch
increased :r. April wh.,e a cons ;stent h:gh number of larvae were t.-apped
frcm Junre to mid-October. Tr.e number declined thr-CghoJu November and
larvae became relatively scarce in DecemTber.
Phaen;cia cuprir.a was the predca.inant fly species collected in this
survey. Table 1 shc.is tnat greater than 97 percent. of the captured larvae
were P. cuorina. One. percent we.e M1. dc-,estica w.:.1 e the re..ainder L~.ere
cc-.pr.sed cf COchli -- ia T:c 11--ia a.or c:u.), hcr : :.llucens (Linna Ls),
cr.d S .co arm pp. T.. c c. ..a., o.- :pc c. s '.-.cs s ,.il r .-: :..cs3
report. Ly tr.2.- :.-.vcs.:;g :c... .- r cxA^ 2. -*r'" cc.,.opr.:s.d S9.'5
3 2""""t -i""I 1
M A M J J A S 0 4 D
Fig. 9. Number of fly larvae
plant during 1969
caught under apron conveyor per week at Gainesville compost
(a Plant closed for repairs June 15-30.
_- less than 20 larvae
Table 1. Percent abundance of species of fly larvae trapped under apron
conveyor during 1969.
Percent of total number of
larvae examined per week
Species Maximum Min mu.m Average
Phaenicia cuprina 100 90.5 97.2
Musca do-nestica 6.4 0 1.0
Cochlio-nyia macellaria 6.0 0 .7
Sarcophaga spp. 4.7 0 .7
Hermetia illucens 4.7 0 .6
Others <.01 0
percent of all larvae collected from residential refuse containers in
southern California (28, 18, 79). It was also the principal blow fly
found in garbage in Orlando, Florida (31). Green and Kane (23) reported
Phaenicia was the predominant genus occurring in London during the summer.
Table 2 gives the calculated number of larvae collected per day under
the apron conveyor and the percent trapped in the larval sampling program
for that same day. These data indicate that an average of 0.99 or approxi-
mately 1 percent of the larvae under the conveyor were caught in the trap.
The variance of 0.04 for these results indicates consistency.
Larval movement into the plant was not limited to the area under the
apron conveyor as migration from a pile of refuse could be expected to
occur randomly in all directions. Larvae migrating from the refuse in the
receiving building in an easterly direction found harborage behind a
wooden retaining wall. This was approximately 1 m from the outer wall of
Table 2. Total number of larvae collected under apron conveyor compared to number of larvae
trapped the same day.
Sweepings Sample Larvae/ No. larvae No. larvae Percent
(Kg) (Gm) sample collected trapped trapped
19.0 976 1741 34,100 487 1.41
27.0 1894 2676 38,200 452 1.17
1.8 200 1500 13,500 114 .84
18.4 642 3842 109,500 986 .89
10.7 1076 6855 67,980 297 .44
14.5 1009 4873 70,250 602 .86
9.8 673 1993 29,100 238 .82
17.4 862 1758 35,731 411 1.15
16.3 611 1796 45,851 490 1.07
22.2 885 3979 97,600 1294 1.31
the building and extended the length of the receiving area. It was
difficult to sample this area and the larval population was an approxima-
tion based on visual observation. It was estimated that the number of
larvae escaping behind the east wall was approximately one-third of those
escaping under the apron conveyor for any given day.
The construction of the receiving area and the practice of handling
the refuse greatly reduced larval survival in other directions. Refuse
was deposited toward the east wall and as it was moved into the hopper
from east to west by the front-end loader, those larvae migrating in a
westerly direction were scraped into the receiving hopper. Northerly
migratioii resulted in little survival since the ramp and paved areas
provided no protected areas for pupation.
Coi-bi6ing the estimates that two-thirds of the larvae migrating into
the plant enter the area under the apron conveyor and 1 percent of these
are trapped results in a population factor of 133. This factor may be
multiplied by the daily larval catch to give an approximation of the
number of insects migrating from the refuse into the protected areas of
the plant. For example, Appendix 2 shows that 6116 larvae were trapped
the week of September 7, 1969. Multiplication by 133 gives an approximation
of 813,428 larvae entering the plant during that one-week period.
Effect of Clearing Receiving Buildinq Caily
Larvae collected under the apron conveyor during plant operation
were compared to collections in the same area during off hours. The results
are given in Table 3 and indicate that an average of 38.5 percent of the
larvae escaping into the compost plant migrated from piles of refuse
remaining in the receiving building after the plant was shut down for the
Total number of larvae collected per day under apron conveyor
caught in the same area during the night.
compared to the number
Sweepings Sample Larvae/ No. larvae Total daily Night catch
(Kg) (gm) sample Time collected catch Total catch
7.22 725 3400 D 36,180
2.95 351 3612 N 31,800 67,980 46.8
11.35 666 2508 D 42,700
3.18 343 2971 N 27,550 70,250 39.2
7.95 360 794 D 17,500
' ]85 313 1961 N 11,600 29,100 39.8
16.8 722 1318 D 30,700
.65 140 995 N 14,620 45,320 32.2
16.3 611 11156 D 44,400
3.35 283 2914 N 34,500 78,900 43.7
19.06 602 1992 D 63,200
2.57 282 2834 N 25,800 88,900 29.1
= 7:00am 6:15pm
= 6:15pm 7:00am
day. It is obvious from these results that not storing refuse overnight
would reduce the number of larvae entering the plant by more than 35
percent and decrease the ensuing adult population.
The value of clearing the refuse from the receiving area daily was
further demonstrated by observing the large numbers of larvae along the
eastern edge of the approach ramp. When refuse remained on the approach
ramp for several days numerous larvae migrated from the refuse and fell
to the pavement below. On several occasions when this occurred fly larvae
were so numerous that the pavement along the edge of the ramp appeared
white. On one such occasion the pavement was swept clean and the larvae
collected 12 hr later. Their number was estimated to be 30,000 or 60,000
per day migrating from the ramp (Fig. 10 and 11).
Adult Development from Larvae
The majority of the larvae that migrated from the refuse were mature
and thus required only a suitable pupation site to develop into adults.
This was demonstrated by placing iO0 larvae collected under the apron
conveyor into waxed paper cups (0.946 1). Twent,-five gm of refuse debris
collected from the same area were added to one-half of the cups. The cups
were covered with cloth, secured with a rubber band, and placed under the apron
conveyor. Ten.days later the number of adult flies that had emerged were
counted. Nine replicates of each test gave an average of 65.3 percent
adult emergence from the cups to which only larvae had been added, and an
average of 88.8 percent adult emergence from the cups with debris added.
Generally there was a considerable amount of debris under the apron
conveyor and behind the east retaining wall, the main areas of larval
infestation. It was concluded that most of the escaping larvae reached
Fig. 10. Eastern edge of apporach ramp.
Fig. 11. Fly larvae along base of eastern wall of approach ramp.
adequate pupation sites and close to 88.8 percent adult emergence wlas
expected. Extending the previous example given for the week of
September 7, 1969, an approximation of 733,313 adult flies could be
expected to emerge within 10 days as a result of larval migration fr-om
Survival of Larvae Through Grinding Mills
Approximately 10,000 mature house fly'larvae were passed through
the secondary grinder in May, 1969. The primary grinder was not in
operation at that time because of equipment failure. Nine live larvae
were recovered in the discharged refuse. In July, 1969, 10,000 mature
house fly larvae were passed through the recently installed primary
grinder. No surviving larvae were found in the discharged refuse.
CONTROL OF BLO. FLIES
Studies were initiated in June, 1969, to evaluate several procedures
such as mechanical control and insecticide baits, fogs, and residues for
the control of blao- flies emerging from the incoming refuse. The
effectiveness of a control measure was determined by the reduction of
flies caught in two baited traps located behind the receiving building.
These investigations were terminated in October with the advent of
Blao Fly Traps
A suitable method to estimate changes in the number of flies was
needed to evaluate the various control procedures. Sticky tapes were
ineffective because the large amount of dust created in the receiving
area rapidly coated the adhesive material. Grill counting was ineffective
because the counts varied with hourly density fluctuations and positive
species identification was nearly impossible (42, 45).
Norris (45) reported that bait trapping was the only generally
useful method available to study blow fly populations and that the bait
employed was the most important variable. He reported that animal tissue
was the best for blow flies, being more reliable than some of the more
recently developed synthetic attractants (14, 45). Ho:-.cver carrion is
not a uniformT bait. Its attractiveness varies with zae, moisture, and
deco:r.iposition (42). Ka.a: and Suenaga (S3) fund that fish 1-da'y-old
vwas tne most attractive to b,1 .-. .'ies.
The traPs se;'ctecd o." L e :: t. cc.pos .b r.. C' e '.o C .< 3 o .\
54 cm :n'.erted cone traps. The- were :ated 'i.1 :-d-y'-olo fish .e Ds
acquired Ioca l'ly. "ns asa of each trap .as encloscc by C.5 c:. sce..-.
wire to prever.t s.:all ar.;rals from sea .g :.'-. b.-: Tncse traps ..
sho.-in in F ; 12.
The tr.ps w'.:ere pieced on the pa'.zr.an: behind the receiving area,
see Figs.l and 15. The flies .were collected frcm the traps daily by
plac .-. the trap and '1 mi of eth',l acetate into a plastic bag. After
the flies %-.cre anesthetized, they were removed and placed in:o a small
plastic bag. T..e catches were then transported to tne laboratory for
coLr.cing ar.d identification.
Tab e 4 gives the ioenrtfication of flies caught in 15 different
daily catches. Tnis shows that 89 percent of the fiies trapped were
Pr.Lcr, icia spp., 6.8 percent were iiusca dciiestica, 3.7 percer.t were
Cochlic.n'-ij miacellar a, an.d 0.5 percent arcoohaqa spp. These figures
are close to those percanzag.s recorded in Table I which gives the
relative abundance of the various species of !arvae entering the plant
frc- the refuse. The differences that occur may be the result of the
trapping method e-.ployed, different survival rates of the species
involved, or ir-migration of adults from surrounding areas.
Fig. 12. Cone trap baited with I-day.old fish heads to sample fly
populations at compost plant.
Fig. 13. Rear view of receiving building showing receiving
hopper and pavement behind building.
Table 4. Sex, species, cr.d abur.nd nc- (;.,, c.f fli is c-ught in con.e tr.a.Ms
baized w\. chr 1-day o'd .:sh -.earls at Ceinesvillie coposci plar:.
erc r.._ C: Co ..
Spez ies .. .. .c.-J_ ,, L.-a *.. .'-, .m-- c
P c-.- r.-c a spp. C3.0 10.4 c' ."
;.LSC ac.-Costica 6. c 1.7 5 .c
Co:hi ia-.'i- -n-cel la.-' a ;.7 55. 2 ,*.:
rco haqa spp. .5 .t'3 iCL..j
atiean of 1- day catches zaken a- random.
F Ild Tests
Several adL't fyi cont.-oi procedures v. er evaluated to ceterm i;ne
their effectiveness and cost of app! cation dur r.g the summer of 1909.
The effaecr eness of th- ccnc.ro proc-cures w-.as determined by c cn-parirg
the number of flies caught per day in baited trap- during the treatment
period to t.ie nur.ber of f' "es ca9ugt dLur-r a prior period of no crea=-
mer.t. T..e duration of pre-treatT.a-.n ccntrcl spimpling wjas 7 days and
subsequent cc.,troi per ocs were 3 days. ,.reatmenc and control periods
were alterr.naed and fo;laJ ed c;h.c.-.olgc.ca'!ly :.i ;he order presented in
Taole 5, beginning July 14,, 1". fcjr :n 5 c'y/: elapsed between a
treatment and the c.auoing control .:r;oc.
The control procedures are descr bed as follao-s:
Sutr bi -- KcK:Ilr ~: al. (1) :n stud~, s L; durops fojr.d ':.i. t
trich.orfon b .:s g ve 'jc o.-.roi cf blo. f'". Sai;,'l c: a ()
re-o.:c.. t-,t di:t.. rvc: ..-. -..: so Ijcr a i:s cc;trollcd ho-se fl :e .
Table 5. Number of flies caught per day in cone traps baited with fish heads as a monitor of
procedures to control adult flies at the Gainesville conpost plant.
No. of flies caught No. of flies caught
per day % per day %
Day Control Sugar bait Control Day Control Sweepingc Control
1 2343 15-18 -
2 2796 19 1197
3 2268 20 2316
4 979 21 1954
5 1050 22 X = 1822 856 53.2
6 3456 23 1055 41.9
7 824 24 908 50.2
8 X = 1959 1178 40.4 25 667 63.4
9 875 55.4 26 353 81.6
10 285 85.5 27 1061 41.6
11 596 69.7 28 1775 3.6
12 1041 47.1 29 1493 18.0
13 490 75.0 30 1437 21.1
14 107 95.5 31 1315 25.8
x = 653 66.7 32 988 46.4
x = 1083 4.6
aNumber of flies caught per day when no control procedures were used.
b400 gm of 0.5% dichlorvos in sugar mixture applied daily as a bait.
CArea under apron conveyor swept daily.
Mean values represent the mean number of flies caught per day for that given procedure (column).
TI11 c $ (CoGt n1u1. I)
INo. of f 1 i s cai.l l;ht
_ _p.er dy
Colitl olflt ait
X> 1 6., 3
> = 831
I,:,. f fl i c, :u L l t
____pr 'd .'
1 9i :
V 5, '
12uC ml o' 1 .0": Cicil orlvc in 5r, rntil t olutioii, ap lied diil 1 a. ca L.i t.
I of 5.0/ feCnthio n in (Jo. 2 fuel oil appr l licJ ith a l ,c-. c : li0o;--aii- s :iI r. iJjer L.I dacl 53,
5'., aJ 55.
Table 5 (Continucd)
No. of flies caught No. of flies caught
per day % per day %
Day Control Dimcthoatce Control Day Control Gardonai Control
98.5 83 1410
99.3 84 = 14]9
g10% dimethoate solution applied at a rate of 2 gm (AI)/m2 to grassy areas adjacent to receiving
Building, one application on day 63.
h0% Gardona solution applied on day 83 at a rate of 2 gm(Al)/m2
x = 1799
Fly Bait, a 0.5 percent dichlorvos sugar bait obtained commercially from
the Fasco Chemical Co., was used prior to this investigation to control
the flies at the compost plant. This bait was evaluated when applied
at a rate of 400 gm per day. The bait was distributed along the conveyor
belt system for a 7-day period beginning on day 8 of Table 5.
Sweeping to remove larvae. -- The area under the apron conveyor has
previously been shaon to contain the majority of the larvae migrating
into the compost plant. To determine the effect of collecting and
removing these larvae on the total number of adult flies, this area
was swept daily for 15 days.
Malt bait. -- Malathion, diazinon, chlorthion, and dichlorvos in
malt or molasses were reported to be highly effective liquid baits for
blow fly control around dumps (76, 31, 34). A dichlorvos and malt
solution was used to determine the value of liquid baits for the control
of flies at the compost plant. Blue Ribbon malt was diluted with
distilled water to form a 25 percent malt solution. Technical grade
dichlorvos was added to produce a 1 percent dichlorvos solution which
was stored at 4 C until used. Fifty ml of this solution were applied
daily to each of 4 locations along the conveyor belt system for a 7-day
period beginning on day 40.
Foqqinq. -- Fogging is not a highly recommended procedure for
effective control of flies since fogging leaves no residue and a high
concentration is necessary to kill flies. However, the effectiveness of
fogging was evaluated since it was used to control flies at the Tennessee
Valley Authority com-post plant in Johnson City, Tennessee (61).
It was observed that the adult blow fl ies, predominantly Phaenicia
(Table 6), left the building at dusk and roosted in the grass irr.mediately
Tab!e Sex, -pcc es, and U.i.-C, ncc ('I' r f. 'c Cc .'lt by L. : t1
ir. Lrass -c cc ." LO rce.: r..] c-r. C Inesv.l il e CG...,c..
Prar.n of -
Spac es flie- c- : .' ,.'...
SI ICcC..S .f II e L L
3. Caught dur:r.g day
Phcanica sp?. 95.2 .3.1 56.
ML sca do esT ica -. 32.3
b. CucLgt a: r.igh-
en c:a .. S .? -.3.7 5 .
"usc, cc- s: '.c .3 S3.7 ..
I;.er. of ten s p.-.ples taken by fi.ve sweeps of net.
surroJndi.-.g :ha plant. Thesa areas were fcged az 9:0O pm or. day 53,
54, and 55 (Tabse 5) e icn a 3 percent fenathion :n \o. 2 fuel o;. sciutior.
d;stricjtt d by a portab:. ht-ci-r suing .ogger. This insectic:d, a-s
selected because o.- avii.biiiy and LaczJse a 5 percent fenzhion soition
k;ll>d 97 perc.-i: of t:-. caged :-.c-se flies 50 m froir a moving foggLr (4).
Resl -al srrais. -- Cc.tact a.id residual sprays are the most oftter.
recorm.ended methods of cc.ntroll ir.; flies. These sprays are r..cst cfrect ve
.whn applied to fading a ras and night-t ire rcting places such cs
shrubs and plant, in th- _irro.dir.ng area (34, 76).
SD;mt.-,o~te gave nme best control of hose fl es in Florida dair', barns
when applied a: a rate of 2 gm (Al)/.,- (5, 9, 10). A 10 percent dimuthoete
'.r. .w :, so.Iu.c i -p. iLc c..cc c.'. dy 3 -y a 2-g: al n F(.57 1) C.r.-
preosed-c Tr r.,. . -.',' c. .-* u ". 2 .,.. i..-../ tne grassy areas
surr c. .- .ac t.'- ., r...
Gardona, (2-chloro-1-2[2,4,5-trichlorophenyl] vinyl dimethyl
phosphate), a house fly larvicide, was provided by Dr. G. C. LaBrecque,
USDA Gainesville laboratory. A 10 percent Gardona in water solution
was applied on day 83 in the same manner as described for dimethoate.
The results of the field tests are presented in Table 5.
Sugar bait. -- Daily application of a 0.5 percent dichlorvos sugar
bait reduced the number of flies trapped by an average of 66.7 percent
when compared to a previous 7-day period of no treatment. This control
procedure cost about $3.00 plus 0.5 man-hr per 6-day work week.
Sweeping to rer.ove larvae. -- The area under the apron conveyor
was swept daily to remove the larvae before they developed into adults.
An average of 40.6 percent reduction in the number of flies was noted
when compared to a previous 3-day control period. This reduction is
considered to be a minimal value. It ..as significantly lower than
expected since previous estimates indicated that 67 percent of the
larvae that migrated into the plant escaped under the apron conveyor.
The difference between the observed and predicted reduction may have been
influenced by the short test period. Since the larvae entering the plant
required 8-10 days to become adults the 15-day study period may not have
been long enough to ascertain the true results of cleaning the area.
Regular cleaning over a longer period should reduce the adult flies by a
factor approaching the percentage of larvae escaping into the area.
A second factor influencing these results was the operation of the
plant during the test period. Mechanical problems prevented regular
operation of the plant and refuse remained in the receiving area for
several days. This resulted in larval migration patterns differing
from those encountered under normal conditions.
Since the larvae entering the plant required 8-10 days to become
adults it is reasonable to assume that cleaning the area once a week
would produce the same results as daily cleaning at a reduced cost. The
effects of cleaning over a long period were not investigated.
The area under the apron conveyor could be cleaned once a week at
a cost of about 4 man-hr.
Malt bait. -- A 51.2 percent reduction in the number of flies was
observed over a 7-day period with the application of a dichlorvos malt
solution. This bait was found to have several disadvantages; (I) it is
not available commr.ercially, (2) it must be stored under refrigeration,
(3) it costs more and was less effective than dry sugar bait, and
(4) its syrupy consistency made it inconvenient to use.
Foqqing. -- The grassy areas of the compost were fogged for 3
consecutive nights producing an average reduction of 68.9 percent of
the number of flies trapped on the folla-ing 3 days. The effects of
fogging were minimal after 1 day as shawn by the post treatment counts
in Table 5. Thus, an effective control program would include a minimum
of 3 foggings per week. This would cost $15.00 plus 3 man-hr per week.
To determine if this fogging procedure was effective on P. cuprina,
100 adults were caught at night by a sweep net at the compost plant and
placed in a gauze cage. The cage was placed in the center of the grass
hill during the fogging operation. After the area was treated the flies
were transferred to a clean cage provided with fly food and water and
held for 24 hr. A control cage was set up and the fly mortal ity obse.-ved
in each. r. is roc .ure' as cd p. 'd .:or c :h treatT.er-. An cVerace
of 97.2 percent of the tre::-d fl ies w- ere dad crter 24 hr whilee 6.1
percent mortal i:y was o'sas.r.'cd in the con;.ol cages.
Pesidual s rav, s. -- A ...C e ., o. ic:tio of dir, thoate gave better
than 95 perccnit cc-.tr3. _.- :.e : ies fc.- c te:e cid re,.-a rned e-,:.: .ve
for 10 days as shoin ii Tab'e : The cost cf cne apl ication vas
approx:.-ateiy $7.00 plus 0.5 m.,n-hr.
Gardcna '..as ir.nefi:ct ive as a r; 'dual spray for the control of
blo.- f i;es as sho.-in in Table 5.
Larvicides. -- Green (22) demonstrated that 59.1 percent orf -,ne
larvae escaping from s, ending refLuse :-a'ns could be controil1c b' dustirng
the area twice wee.
ur.der tne apron ccnv ',,or to control b"..k fl ics iwas rot atte7m.pted because
c: the large amount of debris fall :.-g daily i-to this area. The effects
of the lar.:cide woj.c be short-l: ,ed since incom-ing larvae probably would
not be exposed after 24 hr.
P.rari -c 61 Flies
To screen :n3ect cides ir. the Iaboratory fo,- their effectiver,ess
against P. cupr rna : w firs c r..cesscry to "ind a suitable reari..g
r.edoum so i;rge r.Lr.mors would be a'.vilabl . P. cuori..3 are easily reared
.i t'ie la borator..,' on a c.:t of Lecaying meat bt this medium is odoriferous
and also expor.siv/ .hu .rn l:r : r r._.nbc-rs of fl 's are rc-jired.
lga .'t n P.s s ': b.t a,~. l.T c. r,.. c .. _,r ,;oo.. .. n m Xi. cst i-
gaticr. was sta.r a to c-te.'r .r.. "- ... c.- *-c: .:.her :.._ ria. ,rricht b;
substituted for meat. Two series of tests were carried out which varied
the amount and kinds of test media used. In the first series the test
medium was placed in waxed paper cups (88.8 ml) with 200 P. cuprina eggs
collected from wild flies captured at the Gainesville landfill. Each
cup was then placed in a waxed paper cup (0.946 1) containing approximately
20 gm of dry builders sand. The larger cup was then covered with a
black cloth and secured with rubber bands. Eight days later the mature
larvae had pupated in the sand and the pupae were removed from the
medium by sifting the sand through an 18-mesh sieve. The pupae were
counted and the number recorded. One hundred of these pupae were randomly
selected, washed, dried on paper tacels, and weighed on a laboratory balance
(Mettler, Evanston, Illinois) to determine differences in the size of the
pupae reared on the various test media. Six replicates were prepared
for each medium.
The media tested included the following: lean ground beef; Alpo,
an all meat dog food; Chunx, a dry dog food; Strongheart, a canned grain
base dog food; and Chemical Specialist Manufactures Association house
fly rearing medium (CSMA). Various amounts and combinations of these
media were used as sha-vn in Table 7. Meat was added to several test
media because P. serricata was reared on CSMA fly rearing medium when
provided with sufficient meat for the larvae to develop to second
In the second series of tests 1 ml or approximately 6,500 P. cuprina
eggs collected from wild fl ies were placed with the test medium into
4 x 15 x 30 cm enamel trays. Each tray was placed on approximately 5 1
of dry builders sand in a 40 x 55 x 25 cm plastic tub. A piece of one-fourth
Table 7. Analysis of several rearing media to determine the most suitable method of rearing
Pupca developed Mean weight
Test medium % No. 100 pupae (gm)
a. 200 P. cuprina eggs + test medium placed in 88.8 ml paper cup
10 gm lean ground beef 81.55 163.1 1.513
25 gm lean ground beef 83.05 166.1 2.154
25 gm Alpo 82.4 164.8 2.067
15 gm Chunx + 15 ml water + I gm Alpo 80.1 160.2 1.501
15 gm Chunx + 15 ml water + 1 gm beef 86.4 172.8 1.514
10 gm CSIrA + 20 gm water + I gin beef 73.5 147.0 1.217
15 gm Chunx + 15 ml water 63.05 126.1 1.311
10 gm CSMA + 20 ml water 0 0 --
5 gm CSIIA + 7.5 gm CHunx + 17.5 ml water
+ I gm beef 80.4 160.8 1.533
Stronghcart 59.8 119.6 1.201
b. I ml (c.a. 6500) P. cuprina eggs + test medium placed in 19x30 cm
250 gm lean ground beef 26.5 1723 2.308
454 gm Alpo 34.8 2266 2.226
100 gm Chunx + 400 ml water + 50 gm Alpo 48.6 3160 1.689
400 gm Chunx + 400 ml water + 50 gm beef 62.1 4040 1.719
250 gm CSMA + 500 ml water + 50 gm beef 47.6 3092 1.078
100 gm Chunx + 400 ml water 17.0 1108 1.787
200 gm Chunx + 125 gm CSIMA + 450 ml water
+ 50 gm beef 52.1 3391 1.416
inch plywood with a 25 cm diameter circle cut in the center and covered
with muslin cloth for ventilation was placed over the tub and secured
by 4 bricks. Eight days after egging the medium the pupae were removed
by sifting them from the sand and the total number recorded. One hundred
pupae were then randomnly selected, washed, dried, and weighed. Six
replicates were prepared for each test medium.
The test media included lean ground beef, Alpo, Chunx plus Alpo,
Chunx plus ground beef, CSMA plus ground beef, Chunx, and Chunx plus
CSMA and ground beef.
Rearing tests were conducted on the screened porch of University of
Florida building number 618 which is located northwest of the medical
entomology laboratory. The porch was screened on 3 sides and covered
with a roof with 1 m eaves. Light, temperature, and humidity were
ambient. These tests were conducted during May and June of 1970.
The results of the rearing tests are presented in Table 7. These
data show that i-mmature P. cuprina reared on a diet consisting only of
meat were larger than those reared on the other diets. When large
numbers of larvae were reared, as in the second test series, 4 of the
diets produced more flies than did the all meat diets.
The diet of the dry dog food, Chunx, plus water and 50 gm of ground
beef was cnosen to rear the flies used in the laboratory chemical
screening tests. This diet was superior to all other diets tested in
the nimnbers of pupae produced and cost less than the all meat diets
without producing offensive odors. Although the pupae were not as large
as those reared entirely on meat, these size differences were not
con.sid,.rcd ;reat encugh to ad-ersei' a-fect the teits or offset the
advanzSges of the ccg fco dI-.
Adult bl cow vlis usC in :~ chC-:cal scrcer.ing tests 'were rearec
rC .."i ,>, i co c :c a . ... .: : -
f' s -.ere re.-c to i-. .-. -er. r.---z: .0 c. . -... ... e: cc,'.ii -.:.- c.,
4CU 9gn CV..r.x, -.CO .ml tap .'a er, and S 1, !e .r, gro-nd beef ;.- r:-.-.r..-
described above for the second. :s: ser-e:. Aul: fi ies wr--re h!d .-
15 x 24 x 50 cm- gaSzc.--overed ca, es arc prov ded w ith fras zl: -:zr r.d
fly food daily. The fly food consise. of ,arrs 9ranulaLte sugar,
6 pa-ts nor .-fe d.y i/ i .<, n.d pa.-t c'ied ec-g olk. T'e cages --.ere
:-. d .r. the Un.ivers ity c/ Fl orida :.-aoicl n:C.o g'.. la, o rzz :y
er.,.iro, .ent-- con :tr cha.mn er .' h hr of artificial oa l ight
provide y Ir.ca.,descent lights. Temperature and hu.. idi;/ were ma;r.-
ta:ned a 2 at 2 nd 70 percent -..
Labcratorv Screenina of Insecticides for
Co.nrol of 2. cp. ina
Five-day-old fe -aie P. cuor'na adults '..ere exposed to space sprays
cf 12 ccc.mr.erciall 1 av.ailabIe inscct;cides in the wind tur.nel described
by Dav;s sand Gzhan (15). Tne insecticide solutions were prepared oy
disso!vin each chem.- al in acetonc to attain the desired cor.centrations
(w/v). Thc original range of co.;centr options for eazn chemical was based
on the LC, values obtained fo: .r. insectC:cde SLsceoibl e stri:n of
.-cuse fil:s at -.; LC:.. La.-cra:.-y, C&:2.--lv>;'e.
The tests follaoed the procedures outlined by Bailey et al. (7, 8).
Twenty adult females were confined in test cages made of metal sleeves
closed with screen -';ire at each end. These cages were placed in tne wind
tunnel. One-fourth nil of the insecticide solution was atomrized at 1 psi
into the mouth of the machine, and drawn through the cages by a 4 mph
air current. Duplicate cages of flies were treated with each concentration.
mrrnediately after treatment the flies were transferred to clean holding
cages and a cotton pad saturated with a 10 percent sugar water solution
was placed on top of each cage as a source of food and water. The
treated flies were held under constant light at 250C and at 70 percent
RH for 24 hr when mortality was recorded. If the concentrations of the
chemical tested produced greater than 90 or less than 10 percent mortality
these data were discarded and other concentrations selected until a
minimum of 4 concentrations were used that produced mortalities within
the acceptable range. These data were used to calculate LC50's by the
probit analysis technique described by Finney (19).
Twelve compounds were evaluated in 13 tests, each of which included
from 4-7 insecticides, acetone, a dimethoate standard, and an untreated
check. The chemicals tested were as follows: dimethoate, parathion,
naled, diazinon, fenthion, ronnel, propoxur, carbaryl, malathion, Dursban
[0,0-diethyl 0-(3,5,6-trichloro-2-pryidyl) phosphorothioate], Gardona
[2-chloro-1-(2,4,5-trichlorophenyl) vinyl dimethyl phosphate], and Bayer
41831 [Sumithion] [0,0-dimethyl 0-(4-nitro-m-tolyl) phosphorothioate].
The insecticides tested as space sprays are listed in Table 8 in
ascending order of the LC50 values obtained by probit analysis. The
fiducial limits (P-0.05) are also listed. Dimethoate was the most effective
Table 8. LC50 of 5-day old Phaenicia cuprina females to insecticides
in a wind tunnel.
LC Fiducidal limits LC susceptible
Insecticide (%i P=0.05 hose fly (%)a
dimethoate 0.0259 + 0.0064 0.04
parathion .0532 .0068 .05
Dursban .0567 .0063 .74
naled .0648 .0065 .018
diazinon .0857 .0063 .062
Gardona .126 .0063 .06
fenthion .133 .0065 .15
Sumithion .183 .063 .074
ronnel .246 .065 .13
propoxur .264 .092 .95
carbaryl 8.42 .67 >2.5
malthion >50. .81
aData obtained fror, the U.S.D.A. Gainesville laboratory.
chemical tested and along with parathion, Dursban, naled, and diazinon
demonstrated potential for use as a chemical control of P. cuprina.
Gardona, fenthion, Sumithion, ronnel, and propoxur were less effective.
Carbaryl and malathion were ineffective with 50 percent malathion failing
to kill 87 percent of the exposed flies. Appendix 3 shows the concen-
trations and percent mortalities used in the probit analysis to calculate
the LCc 's. The Chi square tests for chance variation of a homogeneous
population were acceptable at the 5 percent confidence level for all
tests and are listed in Appendix 3.
The CC0 a!ues obt.:rt; by tr.. U JS CIinc.i..i Lascrato.y .;
th Orlan.do SLusc-.t-t .r-in cf h, se- f: les .'or tie in-u, ct ici' s
te -eCd are I isted in Tab> : T.hee '. .. c.h.; c jT.-xc ed tc zi '.- 's
obtained it.-. :: c i . lc.] : c .: -, : '.:. a r;zasc:-. :, ccrr la: a :. eo'en
of :. e chc..:2:s -:C .c J c. -.-. s :.-S a v . s fcr .-c.-c .
bl .ow lies w.thir a factor of 2. The tolerance o. .;. cu L ir to t.ln s,
insecticides zppea.-ed to b. abcL tr sZ. .5 ; as '",0:O cf the u-scC t.,:
house fly s:rair. colc.r i-ze. c.c.- ; '/e,- a.o. Tr.,s is L.-.c~tstLcr,"' .e
s nce the bl a- f;y ..as r.ct been cer.cra.ly expO d ,t3 : o iisect;icidal p-ressuLres
over a -.id spread are3 n the Un:-:d Sta:je.
,.ie Ir.f.fe t e v ensess s f r.. ::.-ic. t to kil C. cuorir.a *..s u.nec oectec
as m.:cr.n;cn res :duz sp-ac's hva -.en re:cG=e..-.d-c to control bic.- fl ies
.t Florida ari'ps (34, 79). Th:s becomes less startling, ho.:.ever, -:hen
one c:nsicers that T..a:tni on. cid not cPr.:.-o1 CL'pr na on shucp in
Australia k57) and znaz r .:cr, has ir.ducea a very specific resistanrce
in the hcuse fly, in CJle: :a-s-: is C q. aid in the blo.- fly, Cr.r'scTivia
outoria Wiea. (1). .n the case of tr. blao fly, cariplate resistance
was induced within 6 months.
P. cusrine are controlle J n. Australia ar.d widespread dieldrin
resistance has bcen reported. 'wild f lics .cre i;c t imes more resistant
to dicldr.n th-n a susceptible strain and resistance, was also obscrvd
to aldrin, endri., isodrin, cr.:crdC..c,, other :yclodicncs, ar.d B..C (32,
67, 6d). Since th, general us- of chlor;nated hydrocarbons is i'iegal
in Florida these chenmca's were not tcstLJ in 2, stjd.,
A shi-t in ;h. cot.-.r.C of b:., .: L. to c.-z- ic p;.osphLas ra made
in Austrc: iO ..-. :.-.: ,a e ;S 's. i&zia ;cn ..~t :t ?rims ry insecticide
used and according to Shanahan (70, 71, 72, 73) no resistance was found
after 6-8 years of use. He terms a 3-5-fold increase in the LD50 values
of wild fl ies as tolerance. Schuntner and Roulston (65) found resistance
to diazinon in blci flies and identified it as the breakdown of the
in vivo pool of free diaoxon. A perusal of the literature revealed that
resistance to any insecticide by P. cuorina has not been reported in
the United States.
DENSITY AND SEASONAL FLUCTUATIONS OF
HOUSE FLIES AT THE COMPOST PLANT
Observations conducted during 1968 revealed that bla, flies and
house flies were present in large numbers in the receiving area and
around the sorting platform, while house flies predominated in the
digester building. These flies annoyed the workers and posed a possible
public nuisance if the plant proved to be a source of flies to the
A house fly sampling program was begun in January, 1969, to determine
the density and seasonal fluctuations of the house fly population at the
compost plant. The purpose of this survey was to determine the magnitude
of the house fly population, the necessity of a fly control program, and
seasonal changes that may affect such a program.
Rearing House Flies
All stages of house flies used in this and the following section were
obtained froa the insecticide susceptible or Orlando strain maintained by
the USDA Gainesville Laboratory. These flies were reared in a 10 1 plastic
tub in a mixture of 1 part CSMA fly rearing medium and 2 parts water. A
6.5 x 6.5 x 10 cm sponge saturated with water was placed in the bottom of
the tub to maintain proper moisture. The tub was covered with a black
cloth secured with rubber bands. Pupae were collected 7 days after
egging the medium and placed in 15 x 24 x 50 cm gauze cages. The adults
were provided with fresh water and fly food which consisted of 6 parts
granulated sugar, 6 parts non-fat dry milk, and 1 part dried egg yolk.
The flies were reared at the USDA laboratory in rooms with 16 hr of
artificial light provided by fluorescent lamps. Temperature and humidity
were maintained at approximately 26 C and 70 percent RH.
Seasonal Fluctuations of House Flies
The digesters were selected as the primary sampling area for adult
house flies at the compost plant for 2 reasons: (1) initial observations
showed that adult house flies were usually more abundant near the
digesters, and (2) equipment operation in the receiving and sorting
areas made sampling procedures difficult.
The grill method of sampling house flies, developed by Scudder (66),
was initially selected for use in the seasonal fluctuation study. This
sampling procedure results in an index of the population and not an
actual measure of population density (43). The reliability of grill
sampling is debatable. Murvosh and Thaggard (43) reported a high correla-
tion between grill counts and the total number of house flies in kitchens
on the Island of Mayaguana, while Schoof (62) found that grill counts did
not increase linearly with the population sampled. Welch and Schoof (81)
reported chat grill counting was subject to individual error and was no
more accurate than visual estimates.
Crill counting rq .na effectt ve at the compost plant because of tne
large .evolu'e of attractive mate .-ials present.
One-foot- square (32.4 cm ) masonite boar'.'- ccvercd Ly a th n la'.er
of Stickem (.ictal e1 nd Pelton Co., Emryv.;le, Califorria) .-iLr w;v-l-:cd
for tracp.ing fl -s i tr.o digc stcr. T .se o rJs '.:ei-e ctt-chcd tc stn.es
I m in I r.g:s .'-.ich v\wru then C:.'v,. :r.to :h- ccO-..ost n .h.. di. c t. -s5.
This procedure \v-.s d .scardc: because scL !arg, r.ur.bers of fl i; vw .-e
trapped that -..- beards becs:.- : .r.crfTct.vat v 2' 'O,- 2 ,- hr a h passed. M.SC,
m.or. than 1000 fla:-s per Zoard wIre trapped and a population recuiction
:his gre t n-ay hove significc-'.t1 y r:uced ch. :ctc: pouLlat'.c,.
F ., st icky tap..:s (Ac-c--.o. ?:.duc.. .... .c.. fo. N.'. ) "ras.rir.g :
o: c. '.:.'re .-t. arr cr :ha s c.y U; C %.:C r shc..n .c be ,s .
TO" trapping :,.e f i e .ayo J d (.5-, S, E) resor-2: --at s:.c',' zta.es
were -,or.e acczur- c t.ha, 11 ccu r.:.c ir. ..:. L ..-. .ouse f 'l poj -D.d.
in Africa because they wrc:-e ass depcndn t on hj.-.on 'udc,-ert, took into
acccnrt temporary :l jctu: o;.-,s in oer.slties, an.d allo.-ed for the de: nti-
fication, cf the fl ies. Sticky tapes nave also been sho.in to be More
accura-e than vaacu.um collect ions .nd visJul co-nts at poultry farms (2;,
.nd baits at dairy bar-s (51). T.sts c.ring Decreber, 1963, revealed that
stzcky ta.cps were accc-: p al for tr-pping ..ouse f, s at tne con..post plant.
ric.sc f lis were sc-.ipled in th-. digesters from January, 12 to
DecezT.mcr 31, 19'9, using st ;cky ;apes sLspn.-.ed from 1.2 rr. .ooden StaKus
driven in-o tne cc-' o... Five stakc, were ,Tp' oy.ed d-ily '.d each s :ke
w.;as placed in a diffcr;r.: 3ag of conpcot va.ry.-.j fro-m l- days of CgJ.
. .k;" : .. .. .* r..-::. ca .y cC i. L.,- r.. .-C, c r.cuse :..s CuL .-.: 01
rc acr. ... e o: t'. ca .os :.. .a. t .per.dcZ r.*c
r uc or: c:.
The mear. numoer o. fl 'e ca.-.t- per sticky tape per ue&k .a cacu-
Sated by 'di.'iT r.; t-e r.j.-b~ C f ;.s ,c ugr.t per w.e
st cky rapes. 7rese ca aa e sn,:.-n i. Fig. 14.
Effects of Te-: .-atre
The' m xrr.'-, au-;; c. ..'- .. l u., .T-:' .': .- re rs '.. cr roGce .. Z 1
3 5e sz..-,ace treat e.n racil t,, .ic.I -s c Ioc'n i me "y ce.".
:o the compost plant. T.i es c-ta .- -a m:Zace av.aiab.e :hro t.-.e
c t-rzesy of Mr. C. '.. Lenrat, n najer of t:e treat..er.:t fa :'/. ri.c
.aeekl', .means of the imzic.ar da1 y s.:- Tpera.ures w.ere calculated ar.d
are sh: .-.o n i n -. . .
A co,.par sot, c. tre rca-. : .e.' c:tch of f. s r. .:-. -- :-rs
th.e rme.,n vjc m:.x mu.. a: r :.-:er :Lrcs sr .... an a:pare-nt corre.a: Cr.
betw.'een- these data fro,. J',uary/ tc J-r.e. T.c cc-r.posc plant was closed
to replace the prTimary grinc :rg mill on June 15, 1959. L'her. ope-ations
resumed c.- Jj1 6, a c ':.'ize c.-op .r' r.u:be,-s of trappea flies v.wa
observed. A. check w.':n tne plant foriT-n -rv ,ealed thsa: he operating
procedures were the same as tr.ose before .he plcr.: closed for repairs.
The oly sserv.aole difference was ch.a the ;e:L.se d:sc:a-rged into Lhe
d;gesters was sl ightly snmal ler in size. There was no reason to bel ieve
thaz this would greatly affc: ,zne nu, e. of :l ies in th. area.
1: wa-s ooserv.ed nmat ter..cerZtures in the digester builainS w.,-re
higher than the -..iblent air :e.T.pcra-:Cu.'eLsbecause o.: the heat generated in
the co.T.pozting p-ocec-a and the cons:.'uction of the il-Il digesting
build ing. A .yc ro t-.rcorcaph was p accd on a platforrmI 15 cm abo;e rne
c -.c :he ; r :c : s .er L:e- w.r, .- .cord d for se ,vera
t-. '0 k r.-: '.".. :.- ..:, :ve.-. :.. 7 :. ,-,.C t t tz-.e eajr daily
* go **
23 9 23 6 20 4 18 1
27 10 24 7 21 5
19 2 16 30 14 28
J F M A M J J A S 0 N
Fig. 14. Mean number of adult flies captured per sticky tape
digesters at Gainesville compost plant.
per week during 1969, in
(a Plant closed for repairs June 15-30.
12 26 9
Table 9. Air temperatures recordeda 15 cm above conpost in digesters at Gainesville c-npost plant.
1969 Wcelk of
Na f ics caught
per sticky tape
Degrees Farenhcit recorded on a hydrothermograph converted to degrees Centigrade.
See Fig. 14.
|m.,x:mnum ir temperatu.:c in the dlcj.ster Lu:lding cculc b- expected cc
exceed 37 C during :he SL--.rT r r.on ns. Appcrently/ hthse tg.-ceuraturei
discourageJ the flics frc.m entering the building resulzir.g in a laer
number of flies trapr-d c,.- the cricky,' t p es.
Tna nur.-,br of f; :e tr:,cc :ncre:-c_ n a.l OcLar .wh.
decrease .-- obsc.',v d .n ne c.-ricr.. -. r .T.p:r.._r- cr.d t:- ,.-.7 .ra. r.
in the b ild:r.:. Tn.;Lu bs 'rv/r.::.". c-..d c.r d-r.c. :a :h.e c-: .'.r :.
the fl ies w.:re re l: i bc.aus c, t.-.e h.gra.- :-T J.- Lr .
r, c c.-C ease -. t:-.e r....nber of f ies ard .-na Zi.b:ir.t ai.- tCeT.,m ratu-c
w s o0asuved in Dec-mber.
Th :s invcs :.; ric.-. V s o.-:c!r.a.-', csicr..cd : dert rcr r.3 :.-.3 s L o.-..a,
.jctuct:o.ns of hc e f :es .a t,-. co-.pos p. n.t. Tr.c tciper:~.-cs .r.
the c:gsrer bui:.ing where t.ne t-aps .'ere located affected the njuber of
fl ies caught d r ing the s_:.....c:- mor.ths and this szu-dy failed in i-s
orisinz. goal. r:c.saver, tns-e c.ta do show a general trea-d during the
cooper m.T.cn-s an: d..ons:ratefd thIt ::'. J.u:.ding design rdJucjd tlhe
number of fl ;es present i -.he di.,st :r building during the p.ricd w-hen
fly r.:.-.bers were ajte.-.:.al. L.'e greatest.
T-.e r.L-:ibe" of flias ca& :, : o.- sticKy' t-pcs placed in the differer.:
ages of cor-post .r, shcha-n in TabLe 10. Thc:. data demonstrate thra
flies prefer the f.-ehly ground refuse. Gretzer th-n 53 pe.-cur. of the
f; .cs in the cigusters r.ormaly congregated in the crea of the 1- crd 2-day-
od c Gpos .
Table 10. Number of adult house flies caught on sticky tapes in different ages of ccnposl..
Percent of total
flies caught in
Days compost in digesters 1-Day old 1+2-Day old
1969 *cek of: 1 2 3 4 5 compost compost
Jan. 12 629 417 434 360 367 28.5 47.4
Jan. 26 266 182 173 91 119 30.8 52.1
Feb. 9 241 150 121 94 105 33.9 55.0
Feb. 23 74 65 44 46 51 26.4 49.6
Mar. 9 28 27 21 36 20 21.1 41.7
Mar. 30 154 130 45 51 12 36.5 67.4
Apr. 20 553 321 123 105 52 47.5 74I.9
May 4 1413 501 193 197 179 56.0 76.9
May 18 501 365 193 154 162 40.I1 65.3
June 1 790 347 228 151 198 46.1 66.3
Jul. 13 99 55 40 26 37 38.5 60.0
Jul. 27 85 106 17 46 32 29.7 66.8
Aug. 10 83 46 45 56 16 34.2 51.8
Aug. 24 176 128 '44 .51 37 36:3 62.6
Scpt. 7 123 116 41 49 79 30.2 58.5
Sept. 21 105 81 69 I4 51 30.4 53.8
Oct. 5 86 134 75 59 88 19.5 50.0
Oct. 19 188 92 91 58 61 38.4 57.2
Nov. 2 407 369 226 201 321 26.7 50.9
Nov.. 16 677 533 675 424 297 26.0 46.5
Nov. 30 971 714 542 407 469 31.4 54.4
Dec. 14I 680 461 437 374 217 31.6 53.1
Evdlut!oon o' F 1, St'c'." Tam .
A nc:n nL -ibe." o .'.c 7. .-.e.re -el i.ce a : ,'r-e t. -cc
screen c.a e w :h sticky :tpo s to c--U..."-i.a if ..-e r.u;.'.3r c. f ic; cLu jht
co '.u d be correlated wr.: t.. coazl .-._.-.b .- 7 f : .-, n:. t -.- ;-
..* Is located in a. p rtially s.-..dad c behi. r. tr -.',in bull i-, c- ..,f 3A
Cair,esv:1 e l oora:ory. The c-ce -hd a 5 x 5 .n aasa wi\ a ccc:c rc;-.
rof0 3.5 m high. The floo.- c.ns sted of soil and :..s ukept claearne o.:
-:weds and grasses jdring the tests. T ..cr 1.2 .i~ states were driven intc the
ground on th.. center l ine c,, r.e ca2e 1 r. fra.. ecch end. A s. ...
was hing on eac-. stake ar.d .-'.Lcud dl. A I xi 1.0 x 1 2 c.m ]"-helf
metal stand was p-ccd ;n the c.ntei- cf th.e cage to .hC.d the food .nd
water SLup ed cally and to provide shelter for the flies. Tests were
coidjctec dr ng June: July, and rugust of O069.
Test insects were obtained as pupac from the LSDA's insectic~ .
susceptible !o..ose fly color, and were held in cages until adult files
were beginning to c-nerge. At the onset of eclosion approximately 200
pupa3e were placed i, a 15 x 24 x 27 cm, cuz z ca~. After 24 hr the
rerimining pupas %,ere removed. The cagcc we.- provided daily with fresh
fly food and v-.ater and were held in a roori provided with 16 hr of arti-
ficial daylight by f:;.-escent lamps. Temperature and humidity were
rmaint ined at 26Z ar.d 7C percent Rn.
Flies used in the test were removed frc., tne cages, anesthetized
with carbon dioxide and counted. A 1:1 ratio of males to females was
SE.LCt n. t,. f'. s ;C.e.u Z..en rel Esed nto .ne large cou:door a;'L.
Sticky t.p... .... r-sac :r. .: cjtaco-r co-e iMUnTdadziatly aftar rel(asin3
the flies. Twenty-four hr later the tapes were collected and the numbers
of flies counted. All flies remaining in the cage following a test run
were killed using a fly swatter. Pupae, 1-, 3-, and 5-day old house flies
were released in the cage in numbers of 100, 250, 500, 1000, and 2000.
Duplicate tests were conducted for all ages and numbers of flies tested.
Ore-day old flies were released in the outdoor cage 24 hr after
placing the Energing adults in the small cages. This procedure provided
flies which were 1/2 24 hr old at the start of each test. Three-day
old flies had emerged 48-72 hr prior to release and 5-day old flies had
ez erged 56-120 hr prior to release.
In one series of tests, mature pupae were counted and placed in the
large outdoor cage. Sticky tapes were hung on the stakes and 24 hr
later the number of adult flies which had emerged during the test was
determined by counting the number of remaining pupae.
The number of flies caught on sticky tapes was linearly correlated
to the total number of flies present in an outdoor cage as shoan in
Fig. 15. A high degree of correlation was noted for flies of the same
age while there was a smaller though acceptable linear relationship in
the combined values of all ages between number caught and number present.
The slope of the correlation was calculated following the procedures
outl ined in Dixon and Massey (16).
The percentage of flies released as pupae, 1-, 3-, and 5-day old
flies caught on the sticky tapes were 11.9, 24.8, 17.1, and 19.2,
respectively (Fig. 15).'
-----o 1-day old, 24.8% capture
--- 5-day old, 19.2% capture
c--- o 3-day old, 18.1% capture
*----* pupae, 11.9% capture
100 250 500 1000 2000
Number of flies released
Fig. 15. Number of house flies captured on sticky tapes within 24 hr after release in
a large outdoor cage.
The small er n-iber cf fli cs trappec wncr. pLpaZ V.aUs zl lc.-.:c tt
e.arge ini the- otdo r cage ve are 7no surprisir.g s r.ce a highe- mcrtal ity
rate w s expected.
C'e err:in:. 'or. f ..'1 1 r1: r. '.TLr f hI- -icjse Fl1 -, O; d Zt ic.-
The total nu,-.,ber of hcuse fI cs in ;-.e digester c'uilc:ng I.;-
est: T.r. ted b/ de:e.m r. in t-ic po -ca- S o r' ked flI :aptP .cd c.-
st cky taes that were rel eas-:s :r. *:a: Z- -c. ...ree-dca old .-...se ..S
fri,-, ;th USDA suscet.:' co' C y :.'ere criesth.at:zed by cac. on r io> d -r.d
placed "..:o small scree- :-.oldinc ca-es. Ti-, e- 'lIes wer e .-arked by
..dd:..g or.e-.a teaspzon of DayC o (Si.zer brot;- rs Ir.c., Cle .-lard,
r,.:o) f;jo,-escert djst to ap. -o.; i.-.T el / 00 ,l i and genzly rotcz inc
t..e cage-s. Tr.e 'lls were c. e. tre:aL er.-ed :o 15 x 2 >. 27 g-uze ca:ee .
Folacwlng a 1-hr period to allc. t:he fl'es to rec'.'rr, the fl es wLere
transzorted to nri- cc'-pos: pian:t .-,d released in zhe digester buiidirg.
A. r'eases were mrri- bet'.-er. U0:00 1 1:00 a cm n a S c-urday or -
S-nday when t.ie plant w-s nort n c erat.cn. Al thugh .il1 the doors ;r.
the c -ilding .wre,-e c!osed, f Ics were not confined to the digester buidir.g
because tne sid.-ng d:d r.ot fiz f:us:h -c the bcse of the bLilding caving
a 25 cm. opening.
The flies w.-re captured by 5 sticky tapcp suspend; d fm .tn tket-s :n
the c;gest.r-. n-d were the si--me as iescr ed previously for :" se.sc-ial
flu c:;ut irn survey. The stick/ t:pcs were collcc.cd 24 hr ;-f:er ccch
rc_ eas. 3.-,0 the rsr--r 1 ': 2 c n i d -' us. C i b-.:ora,, p -,'-r
ui-r ,' ct 1. .:. .o .- rdse- ...-. r.-dc :.-.v lvir.g 1530 -' ic; .-:.:
alnd war, .-.,de i .h 50-0 f is ach.
Ar. v.-erase o. 1.S percent of ,he laoror cor-recrud ho-.- fli e
released in the digcsters %a.are captured on sticky capes ablee 1 ;.
The capture of hose f!ies cn st:cky tape- in a large cutdocr c5- was
s.;o.'-n pr. ioJsl y to b- prop!ryo.a. to .n, ._-o':.-.- o .:l is pretc- r.:.
:.'hi.:ner the percent, c capLurea 17 p rc; r.: as s-c..n ;.or f-c c!
fl ies re:'.ase' it. a out-oor cacg as sho.-.-n .i Fi.. 5o5 o, l.c pec- -.
as sho..n in T7bla 11, 1 .Culd depend on the circJ..s::nces. Ad iteaoy,
any '.lue assigr.nd wojld be questionable due to d-eth, di-parsal, &nc
er.\ i.-on.-ental .actor Hc.-cv- r, in the cres.r.t case t.h- va.ue 1.
percr.: is gIven cred.-.ca since :.ur'vc-h :.id Thagg rdc (-3) counted 1.25
percent. of tie houLc i ies preser.t in a sirr.ilar p rt:iaily open s i:;Jaion.
Ti;s fig-re (l.a pc:cent) can be us.d to estimate the total n.umTer
of house fl es preser.: in :he digestars based on tne numbers cajgh n. on
the LtiC~y tap-s. For example, Fig. 15 sho.-is tha: 48.9 fl ies per stake
per day w.are caS-g.t the aeek of Ap-i! 27, 1939. An estimate of the
tozal number of flies present can be calculated b, ICO percent 1.8
percent x 5 stakes per day x L8.9 fl i s per sLake and is equal to 13,569
hose fl;es per d-y present ii the d:gester building during the weer of
April 27, 19S9.
Recapture of 3-day old markeda laboratory reared house fl ies by sticky tapes hung in
digesters for 2i4 hr following release of flies in the same area at the Gainesville
ccmpost plant during 1969.
No. marked flics
No. marked flies
on sticky Lapes
aDayGlo fluorescent dust.
HOUSE FLY BREEDING IN COMPOST
Observations conducted during 1968 and early 1969 revealed that
house fly larvae were present in the compost in the digesters and
along the conveyor belts where spillage had occurred. The ability of
house flies to breed in compost presented the possibility of great
numbers of flies reproducing in the enormous amounts of compost avail-
An investigation began in April, 1969, to determine the extent and
some of the limiting factors of house fly breeding in compost in order
to devise procedures that may be used to prevent or hamper house fly
Moisture and Age of Compost
Composts of various ages and moisture (%) were evaluated to determine
their effects on house fly breeding. Compost 0, 1, 3, 5, and 10 days of
age was tested at 30, 45, 60, 75, and 90 percent moisture. The age of the
compost was determined by the length of time the compost had been in the
digester. The 0 days of age compost was freshly ground refuse taken off
the conveyor belt just prior to discharge into the digester. Compost 10
days of age was tested prior to and after it had passed through the final
The samples taken from the digesters were removed from a depth of
30-60 cm and placed into a plastic bag. A minimum of 5 areas were
sampled for each bag. The bag was then sealed and the contents thoroughly
mixed. A 10 gm sample was removed from the bag and the moisture content
determined with a moisture determination balance. The moisture content
of the compost in the digesters usually varied from 35 to 55 percent moisture.
Since this was greater than the lowest moisture content tested, a portion
was removed from the bag and placed into a plastic screen mesh bag. The
mesh bag was then placed in an oven maintained at 800C. After a short
drying period, the compost was transferred to a separate plastic bag. A
10 gm sample was taken to determine the remaining percent moisture.
The desired moisture content was obtained by adding tap water. The
amount of water added was calculated by the following equation:
x = z
x = ml of water added per 100 gm of compost
y = moisture content desired (%)
z = moisture content of sample (%).
After the amount of water needed for each desired moisture content was
calculated, the compost was divided into 100 gm portions and each portion
placed into a separate plastic bag. Tap water was added in the amounts
calculated and the bags were sealed and the contents mixed. Fifty gm dry
weight samples were removed from the bags and placed into waxed paper cups
(0.946 I) which were marked for identification. Either 100 eggs or 100
48-hr old larvae of :. domestic were added to each cup. The cups were
then covered with black cloth and secured with rubber bands. Temperature
,nd h-,-;c : y .-rc;e ,r; :ntQ.ain-d -: 2- C -.d 70 p-rccit P.h. Seve.)i cL.y
after e ging or 5 ccys after placing t..e lar'vL. in -:h co-..pS .-e c-ps
were emptied ir.to a p.n of water :nd the cl.-_ting rupa-. '..eri cc'. c:1:
ra d co-.n:ed. Each test -.,s real :ca--d t .--. CS'.A fly r.r .- .
conte:r..r.:g 6 pcrccnt .o:s:u.- w3: uL.LC c ; co. :-o.
;-'o.s:L:e cointer.t a the- 2: o0. t... C3TpI- -: ha tt-1 -!l.- c:.
,-., ,--turatic.-. of 5-,-.." o d ho-u.-- f y l .-v -t-bl 1] ). .o.*. ,.' r, ..-, e
factors c ; r.-l -..-.ce z.-.e a.eve' co.T. .t o.: hcJU -. c frc". ea. -. 1
ages of co.-pos :e:-,.d co.-nta;.-ing j3 -an 75 perce.-.L mc G;tZL r suppc.":ed
hoLS-e f'y development to .c- e:-.tent. i.ne :.'., p,.-cc.-.t -noistur inhkiIt:d
house fl, cac opT. t w.-. 'e 43 percent macis-rc ,..' Ir.surf :cient :o r.a,-
house flecs. Fo.:y-fi.,a perce-. .To;ctur inr. freshly .round rcfise
resulted i.f lass .tn.a 1 pe-cer.: sur ia\ i to ppaL. It should be r.otec
tha: tnese tests uer, sua acted to a.O ientF.,4 (70:1) and moisture
flLctuat:o.-.s duL in t.e tt-. peroc .-ere not r.:;easure.
The zae of tri ccco-,: f-. dect.d ho-s fly development jut ihis was
secondary to moisture as .hc..n ir. Tab!K 12. There was a s:Snificar.:
reduction ;n tne number of eggs that d-vAlopcd o popae .;n 3-cay o.d
ccrr.pos at cj percentt moisture b.t no significant reductions occurred
in tne ages of ccO.post :estica .t 75 pc-'cent moisture.
.he effects o1f Iac.sture Lr, house Pl dIL'I.!opm-ent friom C s .was extended
to cef ir.e more closely h. o : ir,:u.; r.oisture of co,-post for fly oreecir.g.
In this test series 130 M. dcic-st ic e'gs wierc placed .i 3-day old co,-.-os
co:.tc;n :; S5, 6;, 7a3 c tr, d
c;.T.e -.",'.,,.r .. dc, -C; i ,. . L','e. Jic.- .O.; C ..- ,t vwas r: .." T cac?..C:
Table 12. Influence of moisture and age of compost on maturation of immature house flies reared
Time conpostedb Percent moisture
(days) 30 45 60 75 90 Control
No. of pupae collected per 100 larvae (48 hr old)
0 82.5 78.0 84.8 81.6 67.0 94. 1
1 54.3 81.3 58.6 33.5 50.3 92.5
3 84.3 74.3 80.3 88.3 80.1 90.1
5 76.0 80.6 84.6 91.6 70.1 92.6
10 81.6 79.6 86.6 90.3 58.5 92.6
10d 82.8 86.6 89.0 90.5 80.3 92.6
No. of pupae collected per 100 eggs
0 0 0.8 16.5 43.3 5.6 80.6
1 0 0 11.3 33.8 .4 87.6
3 0 0 21.2 40.8 .8 78.6
5 0 0 3.1 39.0 .6 64.8
10 0 0 3.1 25.1 .3 80.5
10 0 0 .3 8.5 0 88.3
Mean of 6 replicates.
Length of time in digesters.
dCSMA fly rearing medium containing 66 percent moisture.
Passed through final grind (finished product).
10 times. CSMA fly rearing medium containing 66 percent moisture was
used as a control. The optimum moisture content for house fly develop-
ment was 75 percent (Table 13).
Sludqe and Grinding
A test similar to the preceding experiments was conducted to deter-
mine what effects the addition of raw sewage sludge and the grinding of
refuse had on house fly development. In these tests either tap water
or sludge (approximately 98 percent moisture) was added to various
grinds of refuse to obtain the desired moisture content. The sludge
was obtained from the storage tank at the compost plant which was main-
tained by the city sewage treatment facility. Sixty and 75 percent
moisture contents were chosen to be tested with the various grinds.
The amounts of water and sludge added to achieve these moistures were
calculated as in the previous study.
Four sizes of refuse particles were evaluated in this study. These
were obtained from refuse taken immediately after primary grinding,
refuse taken after secondary grinding, a 1:1 mixture of refuse from the
primary and secondary grinders, and refuse that had passed through a
small laboratory mill with a 0.63 cm grid. These samples were placed
in plastic bags and mixed with water or sludge in the same manner as
described for the previous experiment.
One hundred M. domestic eggs were added to 50 gm dry weight of the
test materials and placed in waxed paper cups (0.946 1). The cups were
covered and the pupag collected by flotation 7 days later. CSMA fly
Table 13. Influence of moisture on maturation of immature house flies
reared in 3-day old ccmpost.
Percent No. of pupae collected per
moisture 100 eggs
Control b 80.3
Mean of 10 replicates.
bCSMA fly rearing medium containing 66 percent moisture.
rearing medium brought to 66 percent moisture by adding either water or
sludge was used as a control. Six replicates were prepared for each
The addition of raw sewage to compost of all size ranges produced
a higher yield of house fly pupae than the addition of an equal amount of
water as sho.n in Table 14. Such an increase is not surprising since the
total organic content was increased and since Olson and Dahms (49) found
se.rage sludge an ideal breeding medium for house flies.
The effects of grinding compost were not clearly demonstrated. The
results shown in Tables 12 and 14 indicate that the larger particles were
more conducive to house fly survival. However, the size of the refuse
Table 14. Influence of sludge and grinding a of refuse on maturation of immature house flies reared
50:50 Mixture Refuse after Refuse
Refuse after of refuse from secondary passed
Percent primary grinding primary and grinding through
Moisture ca. 8." x 811 s econ da ry m ilIls ca. 411 x lif ]/A" gridb
a. Water added for desired moisture controlf = 85.2).
60 26.3 20.5 19.0 0
75 33.6 29.1 30.0 0
b. Sludge added for desired moisture controlc =8.)
60 31.9 26.3 28.0 2.8
75 47.o 39.5 35.3 19.8
aGrinding samples taken from grinding millIs at the Gainesvill e coiipost plant operating under
bRefuse from secondary grinding mill passed through a small laboratory mill.
cCSMA fly rearing medium containing 66 percent moisture.
particles varied '..i :h r.e daily \-. ar of -.he grinding m:ils and the exact
size r-nge CL1s difficui: to ascert:. n.
The terTp, r.-'z urL s ocx-.'i:'g :.-.c .. / ra.rinr con. incrs J.;
:inves:igczed to c ter.T;nc tiC t n:,r-t.-r.r .-;-', rf -r.e2 b ir,.-.L.
I.'IuO se J : l as i .ne pr - "-. A "k ..A 51. -:I s i co cL c:... .T. -..
(Atkins Inc., C ..'.svy .1 : .? or. c ) .e.- p acec i;. 1i0 1 ic :.-ea.- n;
tu.. ,c.'. :.z. -,: ;.-.g .:'. :-.c -.: "f:'/ ,' r ": rc : .;: ,.:,. : ,o,? '.-e:.." .': .c."s .:"
,."t p'cb:,es w e e.- p, c cc '. t ...;:, 'i ic... c :,e ..:~ ,. e.' .- a r,--, i tc
The t. .i:,e. -jr ,,.:,- .- : .---:.J c.e r, _. :-,.- for,.- J '-ys. 'c'.-. -
waZs rc l i ca: d 3 t i... L-
The mian ..T. -raLure recorcea ; the -'earing tubs at each pcsiticn
are oreser.tefd i.-. TZbL'e 15. T.-,I b! cckc: cat.- ;r. T b. e 15 reprcsenrt
those probes i. areas OccLpied by ia.-rv.e. The mcx mum tczrm.perat-e
observed :." :;-.e larval region b..s L6.1 C. "."t se data indicate that larvae
develc, :.n a tem.perture range of 23 S-.SJ C.
The .c.-.:i.:.un tc.- era. re in whic.i i a.',ature hojse fl ie. can develop
is not kno..an. T.ere are ma:ny rdfercnces deal ing :Wi tenperazure studies
c.i house flies bu : uite defi:. te info.rmiatiron -.'s found concer.ing this
pa.-ticuLr area. Jest (32) sttcCed tht h-cuse fly eggs car.not su..'vive
a temperature tcove ".. l1C while F.c:bajd (59) repor:cd the: larvae died
in 3 minutes when exposed to SJ L.
Tc determ..-.e if zh- temT.erat_.-es tzcir.cd i., ..c d.d -s- -s 7..'y
tre.c.t hojse ,1' d vele;.:..:. :. t c cCT.o .t r. A.:i.-. H 51-. s.;:. co-d. ctc
t.n-.-..c.LA.cr '.;s CSL '' reton e ur. L.'-. e .-T-c.'- .L res. -.'. protes v.ro
1 2. 3 1 2
F ig. 16. Pos it ion of temperature probes in house f ly rear ing
containers (distances in cm).
1Tbl I T1.. Tcni pr.ltur:s oLscrv'cd iin iho".e 1 *, ri rin cci ita incls.
Decgres Cent iqrcadI rccci dcd b d,s aIfLI r
i" r 1 2 -3 I; r 6
1 3I:.9 35. 7 33.9 3C.3 31. 1.
1i0.7 1.9 37.8 33.6 33.3 29.':
3 I6.3 i 2.7 37. 2 32. 3:.8 8. 1
.; ..8 1 .4 /:3.7 37.i' .... 9 3i.0
r 1"3, 2 1: 9 1:1.7 36..7 35. E. 32.,
7 I5.8 C i9.' ':,4. 1 3 0 36. 3 .5
37.1 39,2 3 2 37.0 3'.1 33,2
347 36.1 31 31:. 37 4. 2 .0
SL ricj 1 2.
IL, In of 3 rcpl icatc.s recorded by, an Atl :ri's sc ij con.rlu- icr tliheiiOncLtcr.
CBlockcd data ii..'icate area oLCLIpied b ,' lrvie.
placed in 4-day old ccr.post at depths ranging from 1.27 15.24 cm and
alloIed 10 minutes to equilibrate. The temperatures were then read and
recorded. Twenty-five readings were made at each depth over a period of
several weeks. The temperatures ranged from a mean of 38.20C at a depth
of 1.27 cm to a mean of 59.4 C at 15.24 cm (Table 16). Information on
the temperature in the digesters at greater depths was supplied to the
author by Dr. D. T. Knuth, Environmental Engineering, Inc., Gainesville,
Florida, and is presented in Appendix 4. From these data it can be
concluded that temperature would prevent house fly breeding in the
digester except in the top 2.5 cm of the compost.
Table 16. Temperatures observed in 4-day old compost in digesters.
I 5. 24
M i n imum
Mean of 25 Observations
Sewa e sludge added to achieve 50-55'. moisture content in compost and ca. 1.6 ft per hour of
air per ft- of refuse suJppl ied for aeration.
Neno 2 berain
MIGRATION AND DISPERSAL
Compost plants and other similar types of refuse handling systems
are centrally located to lower the transportation costs. These facilities
are optimally designed to operate in these central locations without
causing a nuisance to the surrounding community. The Gainesville compost
plant has previously been shown to produce approximately one-half million
adult flies per week during the summer months. These flies may disperse
into the surrounding community, thus discounting the value of central
location. An investigation to determine the extent of fly dispersal
from the compost plant was begun in 1969. When the plant closed in
December, 1969, these dispersal studies were completed at the city land-
There is an undue prominence often attached to the maximum distance
of dispersal of flies (63). Flies released from a central location and
recaptured later at some distance in very limited numbers imply that the
area covered is subject to infestation from the release point. Although
this may be true, it should be noted that those one or two flies
rccovarea at some -reat distnr.ce %..ere Xonr thre xcti io.na fe. zat, b,
soe ] c-ient oa c.iaecE, rraqad to Lca. v'e this is -ance. Th: d scE.-al
of th the of the f / pop-'~c.' 7- rat:.e.: zrn.-i that of -- fe. ind v cu:.
is the s i r. ic .'.; cri:e i.- C., o ." a c.:e. Z. .zc rd : n -.*: c:. -. S..'.
(63). T:- d.?p-e:. .l c p::!t' c ..:. i,-s c:p. ctiorn is c :, ;p cec be
ex e., dcd \w::;r.in '/2 2 mi z ccuse o.: -he a:.-;2:..-..g c.-.:r:.- c
hoLSe fl.y rovZT,.-It ( :, 7.E, 5;, 5 6, 6;, SL 75). -T :", m.O/.s f:c.- c-.
;ield of a s:imulurr s c--aus! r.3 a .-opic zaa: :.o. or :, at f cr.oth (3,'.
A fly r..ac/ travel 15 n1 es to r.ch a c s rce I ile :-o it- orig.n (6l).
The attr-ctiveness of the r lease s te may greatly irnflue nce c.spersJ.
Picker.s et a'. (51) recap:uired 1 percent of the liberated house flie
z the .e ezec sit .he...'rr.. r. z:. ., k. a:.
fl ies in an, open area loccrcd at :..e center of a 1 '2 mile circle of L
carns only I..1 pe.rc.in of t..ese fiies were recapTu.-ed. Schoof (63) four.d
that ir. rr. r.y instarn cs flies dispars-d from a location despite tre
presence o n.r. apparent exce-ss oi feeding ar.d breeding areas.
Tnere ae- cCni l ic:;r.g reports of the effects of i o u n rly cIspersal
(25, 40, 52). H.o.-.ever, -he nore com.iiireer.s ive studies of Schoof and
Silverl y (64) four.d th.- ncusu fly movement w.'as not equal in magn;itud in
all directions arnd Pcke.isert c'. (51) r:./alod that fly aispercsl was
ra.-,dc- wner, the w':nc w/as variable and -upw.n:d t.h-n the wind blo.- pre-
cAT, inantl'.' from 1 quartc.-.
C',ata et :1. (.6) demonstrated that hoJse fly d:spersal w.'as not
influenc,- .y hi;n.-iays, rice fields, or rounr air.s. Dispersal is influenced
by tre a;c. snJ : ..; Ti of :h ," .: .,.r, :hc.- no sc."r, i c.-t c '.c..
c,;,.--/ .a ;r. "... .:; : .. .. .. -.:. c ,- .' .., : 2, . f .
Schoof and Silverly (64) concludLd :t;t the cc-.non characteristic of
fly d ipoars:,l was a bS'ic rdr.dcannss of movement ir. flucr.ced by 5 conditions:
i1) popLlat;on pressure, (2) differentially attract ..e site-, (1) geographical
barriers, (4) preferen i:i r.ovenent, c. (5) ir..ijrn:t tcncency of fl ies
.he rrA;m...m ".g.'it r.-ang c i. ;- ccorccd i .- ,o L Js di W,
usually :e r.axirc.J d :st-ice of trp??w ng. Tne nzximur. recorded fl;gnt
of no a. flies is 23 miles (S3,.
E1 o. F ies
C:imor- a (2.) f .d t' .a: z . P .- ,-'ael a.d at ce-.tral point
.cre distr;ib5cd .-cndc;nly after 2 Jc/s in open sheep country. MacLcod
c-.d c.-.r-.ey ( 3, 3 ) co.-,clu-e tn:: bhc' f y cispersal was r ar dor-. Lt
:;,o acscreg3aticns .c.-e fc.-...e p.odLcing a clbmpcd distribution. These
qgg-eCgz .ons ".erLe dJ to aiffe-ent d gra3.s of attraction offer&, to tncse
indivic;a;s ir, tne:r ra.dc.n :.iov rt acro-.s the activity, arcs. These
a:t.ncrs later occided on two types of blo: fly 1 i'"t: a sustained
cispersa; flight, ir.d>pende.: of the enviro-tent, and an i.-terspersal
l :.ght wh::h may :r.voiv n n no r dis l ccc..er.t (40).
GLrnr.y neo .-oc:h: 1.2) .crnd :hat J. cjpr'.na tended to fly da n or
across a p.-Lvc.ilir.g \.'r.d, while Maccod ar.c Donnelly (40) found no evidence
of wi.nd affecting bl -. fly f ight. ",laenicia spp. has dcTons.rat: d a
seasonal n;g.-aL:oi in autumn from the forest to the cities in F;nlzr,d
47) '-r.. f.-0n tr.c forest to opL.n ter. c in .. i G-.;at Britain (36). Pn: menicia
spp. w:s ,nffiLct:Ld oy step slopes of a val ey ;n upllnd Lheeo cCntry
of Grat ;r;c;in t37) ar.c crossec a C;O-y;rv-w la rive,r jnd a SO-ytrd-wide
c c : .-c s.. : 5 -., .-. o-. d tna: b i fl;iess did not fly
during3 hevy ca c- i.-.c -.. =.- -. ; Jir'r i was ,.n aJ i- in daily
active' ity irn .tr a. P. c cr '-. .cs bir:::-. in JZ an, re..-,g ;,cs
n rero s In h e aft -rr c pc-l. : 7'4). Ii:n- a .:" s recorded -.7. -
fr -i : c r ib.cr a: s' : -.!.: i : .- r .).
CcToprehe.ns i'e r.v : .'s o. refcrc- as on f!l.. .'. oispeirs:1 zna
.migration a.e presar.ted b5 JC-.r..c-. - .. .. r r ).
-1] -r "l' I
Fl ight mill s :rcv';de a C:-.r. ni ui m.cr.. of' c sj....': n c:. ac:e.' .7 :s
of .r.sac. l g-.t L.:.J .- conc"ro i e..vi.c.T....;al c d. 0.s. S ir.:e ?
CuL r..-z '..-s crc f.-c.A..:.f.: .: ',, s -i3 a: ..ne coZ posz p 3 li o.-.:c.,/-
reared spc.me:..._ E.,ro a :..c tC o fV'g .t m t aarT.r.e tn i m:x;
disC.:r.c they ,my LC; V ir. d :spers' fl ich:z.
A ;.mp l ccr.s ruLcrt-c f!i t ri' i i as .s.- by .tk ir.s (3) -.' th the
sco.yt id, Dar. -.cc:cnus pFse. :o s e lc. <. .?.is de. e ,.a .as imy,3-,v J
Sr.i;lh -ad Furn:ss (77) ar.d Rc. le,' .: (CD) by ato.Tiacically recording
th- re. iutiorns of t..e mills by ,-.eans of p..D:onelectr.c ce', s and -l ctr.ic
co. ters. Chcrbers and G'Conncl (1-2) furznsr improve' ths e c ic._e by
reduL.Cng t.ne f:Icoc.' of ,ohe ..i .ls ty suppcrt.:n, the pivot bSarzc..-. 2
ThI f. 'gh. mi I s s,.d ir. .'.. scud. ,'ae an-rc-o'ly p.o'.-idod by
Dr. .. L. Eaiiy, JSA, Ga.'n sv;i; Tnr .-c, c-rs of hecs.e ill u.-.,e
cz. s, zruc J frz .i 0.5f r-..: c-,r o. :i- s;tcn 1 r. 1" c :n nC.1 tn, n eand or
this wi .-e w.a ban: : .to 2 r :gCt a.-rl as sh -i.n n F'g. i7, so t.ac. zir.
ze..T.. -, 1 r.. oc" th. '..'. r ..- er.cnc :- 1 S r t .. c." .... .- o."
c-r.~i. 0 3 an l <-.'. .1 o" 1" \.' rs ^.r.rt "i L. :.. :::;... .,- 1.-..i as:-^ ..a
the end of the rotor arm to produce the double end shoxvn in Fig. 17. A
pivot was fastened 16 cm from the end of the arm so that the circle it
described had a c;rcumfrence of I m. The pivot was a No. 0 insect pin
with its head removed which was glued, point upward, to the rotor arm
between two 6 cm circles of paper. The pivot was suspended between two
6 x 25 mm magnets (stirring bars) so that the pin was in contact with
the upper of the 2 magnets and was stabilized by the laoer magnet. The
magnets were supported by 2 wooden doaels connected to a steel rod frame.
The revolutions of the arm were counted and recorded by a method
similar to that described by Smith and Furniss (77). A 6 volt lamp was
attached to the wooden daoel holding the laver magnet as shoan in Fig. 17.
A photoelectric cell was positioned above the lamp so that a 2.54 cm
black paper disc glued on the rotor arm would interupt the beam of light
with each revolution of the arm. This paper disc was 7 cm from the pivot
on the short end of the rotor arm and also functioned as a counterbalance.
The photoelectric cell was connected to a poaer unit which operated an
Flies used in this study were reared on a diet of lean ground beef
in the method described previously. The flies were anesthetized in a cold
room maintained at 2-40C. These flies were then attached to the radius
of the mill with a drop of rubber cement on their pronotum. The rotors
were then immediately mounted on the mills. In one series of tests,
P. cuprina of various ages were placed in constant light provided by
fluorescent lamps for 24 hr and the distances flown recorded. Ten male
and 10 female flies were used for each test.
A second test involved 10 male and 10 female P. cuprina which were
attached to the rotor arm approximately 4 hr after they emerged as adults.
Fig. 17. Diagram of insect flight mill. a-rotor arm; b-magnet;
c-counter-balance; d-light source; 3-photoelectric cell; f-metal
plate; g-cotton ball.
These insects were allayed to fly until death. The flies were allowed
to fly from 8:00 am to 6:00 pm each day under constant light. In the
evening, the rotor arm was fastened to a magnet placed on the metal plate
as shown in Fig.17, and the flies were allowed to feed on a cotton ball
saturated with a 10 percent sugar solution. The lights were turned off
and the flies remained in this position overnight. All tests were
conducted at the USDA laboratory in a room where temperature and humidity
were maintained at 26 C and 70 percent RH.
The mean distances floa n by various ages of P. cuprina attached
to a flight mill for 24 hr are presented in Table 17. The greatest
distance travelled by an individual male was accomplished by a 5-day
old fly that flew 24,129 m. The greatest distance travelled by an
individual female was 19,603 m by a 3-day old fly.
Male and female P. cuprina flew an average of 19,405.4 m and
25,235.2 m and a maximum of 30,127 m and 45,030 m respectively, when
attached to a flight mill until death, as shaown in Table 18. Assuming
these were less than ideal conditions, flies in the field could be
expected to travel these distances and further, especially when taking
advantage of the winds.
Bla Flies Released at Compost Plant
Four releases of wild flies were conducted at the compost plant
during September, 1S69, to determine their dispersal patterns in this
Table 17. Mean distancesaflown in 24 hr by adult Phaenicia cuprina
attached to an insect flight mill.
Age of fly Males Females
(Days) Meters (Miles) Meters (Miles)
1/2 3,671 (2.28) 2,914 (1.81)
1 8,356 (5.19) 7,725 (4.82;
2 11,335 (7.04) 10,168 (6.32)
3 6,341 (3.94) 8,289 (5.15)
4 5,559 (3.45) 10,776 (6.70)
5 10,273 (6.38) 11,438 (7.11)
6 5,556 (3.45) 7,785 (4.84)
7 5,476 (3.40) 7,849 (4.88)
aMean of 10 repl icates.
area. The wild flies were captured by sweep net from the grassy areas
surrounding the cocnpost plant and placed into a large plastic bag. They
were immediately anesthetized by carbon dioxide supplied fro-n a portable
lecture bottle. One teaspoon of DayGlo fluorescent dust was placed in
the bag and the flies were marked by gently rotating the bag. The flies
were volumetrically counted by pouring them into a 50 ml beaker. This
volume represented approximately 500 flies. The flies were then placed
into gauze cages, alloa.ed 1 hr to recover, and then transported to the
release site. Two releases of 1000 flies each were made at the compost
plant, and 2 releases involving 1500 flies each were liberated at the city
animal shelter. The flies were captured around 9:30 pm and releases were
made about 11:00 pm that same night.
Distance flown until death by adult Phaenicia cuprina attached
to an insect flight mill.
Age of Insect Age of Insect
Meters (Miles) At Death (Days) Meters (Miles) At Death (Days)
X = 25,235.2
x 6. 1
x = 19,405.4
A sample of approximately 200 marked flies was taken from each
release and identified. Greater than 99 percent of these flies were
The marked fl ies were recaptured by sweep net after they were
identified by examining the blaw fly roosting areas surrounding the
compost plant with a portable battery powered ultraviolet light. Baited
cone traps, described previously, were placed behind the receiving building,
at the city animal shelter, and in the backyard of an apartment 200 m east
of the plant. These traps were checked every 24 hr for 4 days after
each release. The trap at the animal shelter was removed for those
releases at that location.
An average of 10.7 percent of the blao flies released at the compost
plant were recaptured in the same area 24 hr after liberation as sho.n
in Table 19. Traps baited with i-day old fish heads at the city animal
shelter and behind the apartment failed to capture any marked flies for
these 2 releases. Flies released at the city animal shelter were
recaptured at the compost plant at an average of 5.65 percent. The trap
behind the apartment failed to trap any marked flies in these releases.
Fly Releases at the City Landfill
The compost plant closed December, 1969, forcing the completion
of the dispersal studies to be conducted at the city landfill. The
landfill presented a situation different from the compost plant but
similar in the large amounts of attractive materials present and the
generation of a large number of flies. It was concluded that dispersal
patterns observed in this area may be interpolated as to general trends
which may be applied to the compost plant.
Location of City Landfill
The landfill was located on a 30-acre tract of land north of the
Gainesville Municipal Airport. This area was surrounded by pine flat-
woods and the closest residence was located 1.2 mi south of the landfill.
The Gainesville Industrial Park was located I mi west of the landfill
and the airport runways began 1/2 mile southwest of the landfill. Three
residences were located 1.5 mi north of the landfill while woodlands
extended for several miles to the east.
Table 19. Recapture of wild marked flies by sweep net and baited traps 24 hr after release.
J1o. marked flies INo. recaptured Percent
Date Release site released at compost plant recaptured
9/11/69 Conpost plant 1000 121 12.1
9/1I/69 Conpost plant 1000 93 9.3
9/17/69 City animal shelter 1500 102 6.8
9/21/69 City animal shelter 1500 67 4.5
DayGlo fluorescent dust.
>99 percent P, cuprina.
Operation of the Landfill
The refuse was brought to the landfill by truck and dumped into
trenches 15 m wide and 5 m deep. A bulldozer was supposed to crush and
pack the refuse into the trenches and then cover it with soil at the
end of the day. Such an operation would be in ccipl iance with the
standards of the American Public -lorks Association for the operation of
a sanitary landfill (1). Unfortunately these procedures were seldcn
co-plied with because of equipment failures. Refuse was observed to
remain uncovered for several days on many occasions.
A separate area of the landfill was used to dispose of dead animals
and the maintenance of this area was poor. Too frequently animals were
not coTpletely covered with soil or else not covered at all for several
days. This resulted in large numbers of flies developing in this area
Fly Behavior Patterns Observed at the Landfill
Before a general discussion of the releases can be undertaken some
observations concerning fly behavior at the landfill should be reported.
Blow flies and house flies were inactive at night, roosting on the
refuse or on vegetation surrounding the refuse until sunrise (Fig. 19
and 20). As the roosting sites were exposed to the sun the flies crawled
about the plant or refuse to position themselves in direct light where
they groomed themselves for 15-90 minutes. The flies then left the
roosting sites, flying as it seemed, an orientation flight. These flights
occurred in all directions, with the majority of the flies finally appearing
at a sunny, sandy area, absent of vegetation. The sunny sides of the
mounds of sand used to cover the refuse were preferred sites. The flies
Fig. 18. Fly larvae in animal disposal area of city landfill.
Fig. 19. P. cuprina roosting on grass tassel at night at city
Fig. 20. Predominantly M. domestic roosting on weed at night at
Fig. 21. Predominantly C. macellaria with some M. domestic roosting
on dead brush in refuse at night at city landfill.
sites. House flIies and P. cupr i_,a were both observed to f ol Iow th is
pattern and both occurred in the s;,me mating area s simultaneously.
The roosting sites were centered around the most recently dumped
refuse. M. domestic rested on the refuse, especially brush in the
refuse, and on the surrounding vegetation immediately adjacent to the
refuse. There appeared to be little selection of plant species chosen
as resting sites but there was a preference of height. House flies
appeared most often on plants 1/2 I m in height, House flies have
previously been reported to roost preferably on ceilings, trees, and
shrubs in rural areas (2, 33, 41).
Cochliomyia macellaria were observed to roost on leafless or dead
branches 1-3 m in height. Brush in the refuse and plants immediately
next to the refuse were preferred (Fig. 21).
P. cuorina was seldom observed roosting on the refuse and rested
almost exclusively in grasses and weeds up to I m in height. Green (22)
and Maier et al. (41) observed similar behavior at a slaughterhouse as
well as in urban areas. These flies roosted at a greater distance from,
the refuse than did the house flies. If one walked from the refuse
through the surrounding vegetation, he would first pass through a belt
2-5 m wide of plants containing roosting house flies. This zone would
give way to a mixture of house flies and bcloq flies and finally to an
area where the blow flies were in the majority. The number of flies
decreased rapidly with increasing GistGriCe from the refuse. Flies became
relatively scarce after about 20 m.