The white-fringed beetle, Naupactus leucoloma boh.

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Title:
The white-fringed beetle, Naupactus leucoloma boh.
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Language:
English
Creator:
Young, H. C ( Harry Curtis ), 1918-
App, Bernard Auman, 1906-
United States -- Bureau of Entomology and Plant Quarantine
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United States Department of Agriculture, Bureau of Entomology and Plant Quarantine ( Washington, D.C )
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aleph - 30261293
oclc - 778358983
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AA00022939:00001

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3-420 January 1-38

United Sttes Defaa't5,t oL Ut L2W
Bureau f Entomolo and Plant -iarantine


THE WHITE-RINGED BEETLE, NAUPACTUS LECOL0MJ BOH. l/

3y 1I. C. Young, B. A. App, and G. D. Green, Division of Cereal
and Forage Insect Investigations, and R. N. Dopson, Jr., Divi-
sion of Domestic Plant Quarantines



Introduction

The first report of the appearance of the white-fringed beetle
in the United States was made by the Division of Insect Identification
in the Bureau News Letter dated September 1, 1936, when it was reported
that L. L. Buchanan had identified as Nauractus leucolona Boh. two spec-
imens received from A. N. Tissot, of the Florida Agricultural Exreriment
Station. These beetles came from the area around Svea, Okaloosa County,
Fla., and at that time were reported to be injuring peanuts. In the
October 1, 1936,.issue of the Insect Pest Survey Bulletin J. R. Watson
reported that this insect had appeared during the summer in the north-
ern part of Walton County, in western Florida, and in adjacent areas in
Alabama, where it was causing much damage to peanuts and some injury to
cotton and other plants.

J. R. Watson, of the Florida Agricultural Experiment Station, and
U. C. Loftin, of the Bureau of Entomology and Plant Quarantine, made a
brief survey of the infested area in Walton and Okaloosa Counties, Fla.,
on May 14, 1937, and an account of their observations is given in the
Bureau News Letter dated June 1, 1937. At that time the larvae were
reported attacking cotton, corn, peanuts, and velvetbeans.

This insect is a native of Argentina, Chile, and Uruguay, in
South.America, and has recently been discovered in New South Wales,
Australia (Rev. App. Ent., vol. 21, p. 303, 1933), where it was "attack-
ing the roots of lucerne."

The research upon which this paper is based was started at
Florala, Ala., on June 23, 1937. This work has been under way for too
short a period to cover all phases of the life history, but a brief sum-
mary of the data secured prior to January 1, 1938, is presented herein.


l/ Order Coleoptera, family Cuculionidae, subfamily Otiorhychinae,
tribe Spicaerini.







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Present Known Distribution in the United States

e lm'est i:non Infested area centers -.round Floraia, Al9.., and
Iies in the States of Alabama and, Florida. This area covers approximately
27 square miles. Smaller infestations have been found at Pensacola, Fla.,
Laurel, Miss., and New Orleans, La. The infestation at Pensacola includes
26 city blocks, and only a small number of specimens have been found there.
At Laurel, 1V[iss., infestation has been found over 1.1 square miles, and
most of this area lies within the city limits. The infestation at New
Orleans includes approximately one-third square mile and lies near the
doc's along the Mississippi River. All the/adults found at New Orleans
late in September were dead, but living larvae were found in this local-
ity during November.

Another very similar species, which has been identified as
Naupactus sp. and tentatively as a new species, was found in southern
Mississippi. Infestations of this were found at Gulfport, Landon, and
Saucier in Harrison County, and at McHenry in Stone County. The feeding
signs of the adult are very similar to those of the white-fringed beetle.

Stages of the White-Fringed Beetle

The adult

Description.--The adult beetle (fig. 1, A and B) is seven-
sixteenths of an inch in length and about five thirty-seconds of an
inch across the abdomen. The color is dark gray, with a lighter band
along the margins of the elytra, and two paler longitudinal lines on
each side of the thorax and head (one above and one below the eye,
fig. 1, A). The body is densely covered with pale hairs, which are es-
necially long on the elytra. The underwings are present but very rudi-
mentary and vary greatly in size with the individual beetles. ThQ elytra
are fused together, and the adults are incapable of flight.

Activities of the adults.--In 1937 the adults began to emerge about
June 15, but according to farmers in the Florala arca none was seen in
1936 until July 1. The peak of emergence .-as reached between July 7 and
July 11. After emerging, the adults crawl to the nearest favorite host
plant to feed and pass the -rreoviposition period.. On cotton plants they
congregate in clusters near the terminal buds but usually on the underside
of the leaves. In -eanuts the beetles are usually found on the lower part
of the vines near the surface of the soil. Beetles in corn that is not
intercropped with velvetbeans or peanuts migrate therefrom in search of
other food.

After several days of feeding the beetles begin gradually to
disseminate over the plants. When ready to deposit eggs the beetles
have become well distributed over the plants, either individually or in
small clusters. The ground activity is very limited until egg deposition
commences, i rovidd favorite host plants are present. The beetles con-
fine their feeding to the outer margin of the leaves, usually the portion
of 1 af nearest the petiole. They iorcfer the older leaves of all plants
rather than the tender buds. They feed often but consume no great quantity







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laf surface. On cotton T2lants 3(Y inches in hciht, where 100 t, 2C0
beetles fel for 6 to 10 6ays, JeS Ghali 50 Tercont of the leaf racee
was consulted. On velvetboanrs, 100 To 15C beetles hive been obserw
to food for scvcral ivecks without consuming movre than "T5 percent of
the leaf surface. In a few instances where aanut5 odjoined heavily
infested cornfiel !s the adjacent rows of peanuts have been totally
stripped by the hordes of migrating beetles.

Observations made at various hours urgingg the diy and niiht showe-
less activity at night than during daylight. After egC depositions begins,
the beetles feed and rest on the lower p',rts of the rl,.nts. The period.
of greatest activity is fr:.m 1 p. m. to 4:30 n. m.

After the beetles have passed the preoviposition period they ave
the plants to deposit egs. At the cnd of each lay's activity thcy come
to rest on the lower portion of a plant or may rest on the ground if
there is sufficient cover of 7rass or weeds to conceal them. The migra-
tion is more or less a gradual dissemination away from the areas where
they umergod or passed the prcviros ition ruriod. The beetles do not
move any great distance per day but gradually keep moving in the stne
general direction day after day. The seasonal movement covered from one-
fourth to three-fourths mile, 'er rning on the tye of vegetation in the
path of the beetles. The movement is greatest over areas bearing scant
vegetation and less over areas covered with dense vegotaticn. The
beetle's habit of investigating practically every plant in its -ath
prevents it from moving any gr at distance.

Parthenogenesis.--So far as is known there are no males. This
insect reproduces parthenogenetically. Dissection of more than 2,300
adults collected in the field in the Florala area showed that all the
individuals were female. Thirty-two beetles were reared from larvae or
pupae in the insectary and were confined separately from the day of
emergence in small jelly glasses with soil and foliage. Every one of
these individuals deposited fertile eggs.

Abundance of adults.--In a heavily infested cotton field one
man collected aprroxisately 80,000 beetles froi one-half acre in 4-
hours on July 14. As the bag-and-hoop method wa's used lor coilloocting
the beetles shaken from the plants and only, about two-thirds of t; c
beetles were captured, they were present at the rate of about 243,0DC
per acre. The average population was 45 beetles per plant. Approxi-
mately 50 percent of tho plants in this field hod boon C"estreje by
the larvae, end. thn stand -.,vs only 3,000 r2..onts ror ecre.

During the period inx1edistely after emergence, July 7 to July 20,
it was common to find from b0 to 100 beetles ncr ] lant in the infested
cotton fields, and from 150 to 200 beetlcs were tken from individual
plants in Lhe heavily infested portions of cotton ficldIs. On July 10,
250 beetles were taken from one cotton -lant, 78 from one vclvctbcan
plant, and 44 from one peanut plant. As late as September 6, C2
beetles were collected from one cocklebur plant, 188 from one velvetbean
plant, and 30 from one cotton plant.






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The seasonal decrease in the abundance of 1ults, was checked
during the fall by making daily counts of the number trapped in desig-
neteA sc-ctions of a barrier trench surrounding a corn and velvetbean
field. During the period of September 20-24 a total of 1,037 beetles
were caught. The number captured decreased to 213 for the period of
October 10-14 rnd to 130 for the period of October 30-November 3. Only
24 beetles were captured. during the period of November 9-13 and 2 during
the period of November 19-23. The last beetle captured in the sections-
of the trench under observation was taken on December 5; however, living
beetles were found as late as December 18.

Preovi-nosition ecriod.--The average preovipoition period for
32 individuals reared in the insectary was 11.4 days; the periods ranged
from 4 to 37 d.ays. These beetles were fed on cotton or oeanut foliage.

Oviposition recordG.--Comnlete ovinosition records were secured
from 32 beetles which were reared in the insectary. A total of 25,302
eggs were deposited by these 32 beetle., ranging from 83 to 1,847 eggs
per beetle, with an average of 790.7. The greatest number laid by any
one beetle ii one day was 137, and the daily average was 9.2 eggs, per
living beetle. These beetles emerged from July l0 to July 31, and the
egg-.eposition eriod ranged from July 15 to November 29.- Ton of the 32
beetles deposited more than 1,000 e.gs each.

Partial ovipo-ition records were secured for 40 field-collected
beetles. ece beetles were not collected until July. 20, consequently
only a par-,ial record wo's secured, since adults w-7ero already depositing
eggs-under field conditions. These 40 beetles deposited a total of
20,496 eggs. or an average of 512.4 per beetle. The egg-deposition
period e.:toi.ded to November 29, and the last beetle died on December 4.
The daily average was 9.8 eggs r living beetle.

Postoviposition neriol.--The average length of life after deposi-
tin- the last eggs was 13.6 days. A few beetles deposited eggs on the
date they -:ied, Out the majority lived for a week or more after egg laying
ceased.

Lenth of life of adults.--The average length of life for 32
beetles ]ept under insectary conditions was 96.9 days. The total
len'gh of life wac divided as follo-7s: Preeviposition period 11.4 days,
oviposition period 71.9 days, nnd nostoviposition period 13.6 days.
The maximm length of life v i, 147 iays for a beetle which emorgu-d on
July 21 and died on Docomber 15.

The effect of no food and of different foods on the longevity
of adults ....Iewly emerged beetles kept without food did not deposit eggs.
The average longevity was 13.3 datys and the maximum was 46 days.

The available food T)lants affect the length of life of the adults.
On August 2, 160 beetles were collected at random from a cotton field;
40 were fed on peanut foliage, 40 on cotton foliage, 40 on grass, and
40 were kept on moist soil but without food. The beetles kept without
food lived only a short Teriod. The average longevity was 8.2 days and










the maximum was 12 days. The averxge longevity of the beetles fed on
grass, cotton, and oepnut fclib e was 17.2, 32.8, mi A7.5 days, respect-
ively. The maximum longevity of the beetles fed on grass, cotton, and
peanut foliage was 44, 129, and 1,71 days, resectivcly.

Another series of adults were collected on Auuxst 4 in an
abandoned field. where they ha l been feeding on wild host plants, which
consisted mostly of blackberry bushes. These beetles "icre divided into
two lots, one lot being fed on cotton foliage and the othcr on blackberry
foliage. The average longevity of the beetles fed on cotton was 33.4
days, and the maximum was 122 days. The average longevity of those fed
on blackberry foliage was 26.1 days, and the maximaJm was 81 days. The
beetles fed on blackberry foliage did not live as long as those ferl on
cotton but they lived considerably longer than those fced on grass.

The egg

The egg (fig. 1, C) is approximately 0.9 mm long and 0. mm wide,
and is oval in shape. The color when freshly denosited is milky white:
the color changes to dull light yellow after 4 or 5 days.

The eggs are deposited in rmasses, ranging in number from a few to
as high as 60 or more, but th- usual number is from 15 to 25. The indi-
vilual eggs and masses are covered with a gelatinous substance which makes
them adhere to one another and to objects or the soil.

Place of deposition.--The eggs are deposited at the point of con-
tact between soil and objects such as sticks, gravel, lant stems, and
other things lying on or protruding from the ground. in some instances,
where the soil is easily penetrated by the ovipositor, eggs are deposited
directly in the soil. The depth of the eg:us in the soil ranged from one-
sixteenth to five-sixteenths inch. Tn a fOw instances egg masses have
been found on plants as much as 1-1/2 inches above the surface of the
soil. Egg masses have been found on cotton bolls, seed cotton, pecans,
maypops, and corn husks where they were in contact with the soil. In
fields cropped to cotton the previo-as year, the arts of the old stalks
that are partially covered .'ith soil seem to bc favorite places for egg
deoosition. In peanuts and Me::ican-clover thc egg :naszcs arc ofton
found attached to the underside of the stems where they are in contact
with the soil. The beetle prefers to del-osit eggs in shaded places be-
neath plants, but the greatest cgF.-laying activity occurs between 1 and
4:30 p. ri., i. e., usually during the warmest -art of tle day.

Duration of the egg stage.--Eggs were rPmove- from the jelly
glasses where deposited in the laboratory and y1laced in metal save
boxes on moist blotting paper for incubation records. A fow drors of
water were addi.d as needed to keep thc blotting raper moist throughout
the incubation pc2iod.

The incubation periods for eggs deposited from July 15 to
September 2 averaged 14.3 days, and 85.5 percent of the eggs hatched on
the 12th to the 15th day inclusive. After September 2 the incubation
period increased. The average incubation period for eggs deposited from






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September 3 to September 12 was 18 (lays; September 13 to September 22,
20 days, September 23 to October 2, 23.3 days; and October 3 to October
12, 4'l days. Complete incubation records are not available at present
(Jani'ary i) for eggs deposited after September 25. Eggs deposited
after this date have hatched very slowly, mny requiring more than 60
days.

The incubation periods: for 13,766 eggs deposited from July 15
through October 12 are given in table 1.


Table l.--Average length, in days, of the incubation period for
eggs of the white-fringed beetle deposited on the dates given

Incubation
Date eggs Number of period
were deposited eggs (days)

July 15-24 1,988 15.1
July 25-Aug. 3 3,128 13.4
Aug. 4-13 1,76- 1-1.3
Aug. 4-23 753 16.0
Aug.24-Seot.2 887 16.5
Sept.3-12 1,822 18.0
Sept.13-22 1,163 20.0
Sept 23-Oct 2* 1,031 23.3
Oct 3-12* 1,231 41.0


*Incubation periods incomplete.


No larvae have emerged from eggs deposited mrior to July 23,
when the eggs were kept under dry conditions. As late as December
20 those eggs were still viable, as is shown by the fact that larvae
emcrgd within 3 days after the eggs were placed under moist conditions
at natural temperatures. Larvae emerged from these eggs within 3 hours
after they were placed under moist condition at a temperature of 700 to
800 7. The larvae within such eggs are fully developed. Apparently
moist conditions are not necessary for the development of the larva
within the egg. The moist conditions which are apparently necessary
for the emergence of the larvae from the eggs also cool and soften the
soil, making it favorable for the newly emerged larvae.

The larva

Description.--The full-grown larva (fig. 1, D) 2/ averages approx-
imately one-half inch in length. The body is yellowish white, fleshy,


2/ The illustration, lateral view, of the larva (fig. 1, D) was
made from a specimen preserved in fluid and is an accurate representation
of that specimen. The foregoing description was made from living larvae,
and any discrepancies betweeft it and the drawing are due to distortion in
the preserved material.







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more or less curved, legless, and sparsely covered with hair. It con-
sists of 12 much-folded segments, which are int-rrupteti by two sub-
lateral longitudinal grooves running the length of the body. The
dorsal portions of the segments are bulging; the ventral portions are
flat. On the sides, above the longitudinal sc-7arttin grooves, small
spiracles are present on all segronts except the s'ccon1, third, and
twelfth (last).

Feeding_ habits of the larvae and the innJey they cause.--The
principal damage is caused by the larvae feeding on the roots of the
young plants in the spring. The lower part of the stem and tnProot
are chewed away, but the smaller lateral roots 're not attacked. In
many instances the larvae burrow into the seed and devour the contents
before the young plant has had sufficient time to appear above the
ground.

On most plants such as cotton, velvetbens, peanuts, field
peas, and sweetpotatoes the larvae consume the fleshy portion of the
underground stem and taproot, usually leaving the tougher central
portion. Only occasionally is the stem or root comoletely severed
and then only in the case of very young plants. On larger plants the
larvae may feed only on one side of the root and then for only several
inches.

The feeding on corn and sugarcane is somewhat different from
that on other plants. On these -olants the larva cuts a small hole one-
fourth to one-half inch in diameter into the main stem, usually burrow-
ing one-fourth to one-half inch into the stem, but has never been observed
tunneling along the root for more than 1 inch.

The major portion of the feeding on roots during the spring ex-
tends from the surface of the ground to a depth of 6 inches. Where the
feeding is severe the plants turn yellow, wilt, and dic. Where only a
small section of the cambium layer is eaten away the plants survive but
produce very little or no crop. The larvae undoubtedly feed at greater
depths during the summer as the root systems of nlzxnts extend downward.

The larvae are very general feeders and caused serious injury
to field and garden crops in the Florala area during 1937. The infesta-
tions are still localized on many farms, but the yields were materially
reduced in many fields. In some fields as high as 90 pcrcent of the
plants wore killed in areas ranging from a few sqiaro yards to an acre
or more. In many instances, after the larvae had destroyed the stand,
the fields were replanted and the larvae then dtstroyied the second
planting. In heavily infested spots the larva( not only killed the
cultivated crops but also the grass and weeds. Late in June and early
in July these spots were barren and could easily be detected at great
distances. After the greater number of the larvae matured and emerged
as adults, a heavy growth of grass developed on the former barren areas.

The larval injury to peanuts occurs at two distinct periods. At
planting time and shortly thereafter the larvae feed on the planted seed
and on the roots of the young plants, thereby damaging the stand. The
adults after emerging concentrate on the remaining plants and deposit






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eggs in the area immediately surrounding the slants. Later in the season
the newly emerged and older larvae attack the developing nuts, chewing
away portions of the hulls, and often boring through the hull and destroy-
ing the kernel. The nuts of chufa are injured in the same manner as are
those of peanuts.

During the fall larvae have been observed feeding on the under-
ground stems and taproots of cowpeas and. peanuts after these plants had
matured and died or had been killed by frost. Evidently the decaying
roots furnish a desirable food for the larvae. In one field the soil
from around 96 cow-oea plants was examined, and an average of 16.6 larvae
per plant was found. An area 4 inches in diameter around each plant was
examined to a depth of 6 inches.

Larval development.--Newly hatched larvae were found in the
fields on July 27, and it is highly probable that some new larvae emerged
several weeks previously. There were many larvae in the soil during
July that appeared to be fully matured but which did not pupate, and no
pupa.e w re found after Augst 1. These largo la".rvae were active through-
out the suimcr, feeding principally on Mexican clover, but during the
fall they fed very lightly when compared with larvae that hatched during
July and August 1937. No reason is known for this carry-over of apparently
mature larvae, and the maximum and minimum length of the life cycle is
still to-be determined.

The newly emerged larvae are capable of living for a long period
without food. On August 13, 197 newly emerged larvae were confined in
salve boxes without food, soil, or moisture. The average length of life
for these larvae was 24.2 days. On September 1, or 19 days after hatch-
ing, 49.7 percent were alive. One month after hatching 29.4 percent were
alive. The last larvae lived through October 24, or 73 days.

The larvae are not entirely dependent upon plant roots for devel-
opment, at least during the early stages. Larvae hatched during August
have been kept in sifted soil and have developed in size as well as other
larvae that were provided with plant roots. It has not been determined
whether larvae can develop to maturity without feeding on plant roots.

Vertical distribution of larvae in the soil.--In order to determine
the distribution of the larvae in the soil, diggings are being made in
infested fields at intervals. The larvae are removed from the soil by a
combination process involving washing through a series of screens and
flotation in a heavy solution. It is realized that soil type, soil
moisture, available food material, and possibly soil temperature, affect
the vertical distribution of the larvae. Usually the distribution is
the result of a combination of these factors. Because it is impossible,
in the preliminary work, to separate the results of the diggings and to
group them satisfactorily according to the factors involved, the vertical
distribution of the larvae for all diggins made on or near a definite
date are grouped together in table 2.







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Table 2.--Vertical distribution of white-fringei beetle larvae in the soil


Depth
(inches)




1-6

1-9
1-12
1-15
1-18
1-21
1-24

M ean depth
(inches)
No. of larvae:
in sample


Accutiulative -ercentage of white-fringe4 bcetle larvae
found at different deaths in th; soil
Oct. Oct. Nov. 4,ov. ec. D
8-15 20-21 9 22

27.8 24.3 50.0 0.0 4.5 3
70. 1. 63-6 77.6 0. 78.8 - 8
88.9 79 3 90.8 'I (I C-) I
047 "* 93.4
9".-4 86.4 94. 7 9 9.0 4 .
95.4 92 8 98.7 99.U .. 98
98.2 97.1 98.7 r)1D..1
92.1 100.0 100.0 99.0I0.
100.0 i00.0


5.25 4 .18 4.02 4. 1 4.15

1-08 140 76 ].0062 ,jc


The mean depth (luring October ranged from 5.25 to 6.19 inches,
but it was fairly constant during November and December, when the ranie
was from 4.02 to 4.21 inches. In the diggings rmnde Jurings November and
December from 94.7 percent to 98.4 percent of the larvc were in the
upper 12 inches of soil and more than 90 percent zicrc; in the uppor 9
inches. The percentage of the total number of larvae *,n the upper 3 inches
during October ran :ed from 88.9 to 79.3. Larvae h-ave boen ta ken in the
layer of soil 21 to 24 inches below the surface.

Larval pooulation.--During November and Dece2ber larvlal-pntu!a-
tion counts were made in a rm-nber of field; throughout the Florain area.
The results have been grouped according to the crop rown in 12'37 and
are presented in table 3.





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Table 3.--Larval population of the white-fringed beetle in 41
fields planted to various crops, Florala, Ala., November
and December 1937.


IThmber of larvae
Number per square yard
of________________
Cro o
fange Average



Cotton 13 8-718 147
Corn 5 0-103 41
P eanut s 12 0-1,041
Cotton (intercrorved) 1 Z-4
Corn (intercrorpel) 10 O-EO 178


Average 0-1,041 184



Forty-one fields were sampoled, and 5 of these showed no infesta-
tion. The number of larvae per square yard in the infe-ted fields
ranged. from 8 to 1,041, or f'rom. 38,71C to 5,033,440 per acre. The average
population in 13 cotton fields was 1,17 larvae ror s'7u'rre yard; in 12
peanut fields, 283 larvae per squ.-re yard; in corn fields which ;o.re
intercromei with velvetbeans or peanuts, 193 larvae er square yard;
and in 5 corn fields which vwere not intercroorcd, 41 larvae T.or square yard.

The pupa

The pupa (fig. 1, E) is approximately seven-sixteenths inch in
length, and when first formed is white. Parts of the body and frc-,,enda-
..es.. S ht before transformation.

Just before aviation the larva -D.a%,re, a neat earthen cel
nd lines it with a secrotion fro:-, the bod.. t rUp teo i-not f ro m
3 to 6 inches below the soil surface, ano the cuol cell is a roxi-
mately three to four times a' ior 7 as the Tu). n. Tho longitulinal axis
of the -u-ral chamber is on .%n inclined rlano, :.nd the e:it tunnel is
usually, cvt nt roximatcly the s-am on'lT until tho adult is -vithin 1
inch of the surface and then it usually m'kes the exit hole perpendicular
to the surface.

The date when pupation begins has not been ascertained. Loftin
ani atson lid nct find any ure.e in the nr i:a around Sveon., Fl. on
,,y 14; pulae were abundant, however, on June -. and '. few ndalts had
already emered on that date. Most of the adults had emerged by July 15,
but nn occasional pupa could bo found during the last part of July. No
piuae were foundI aL'ter Aagust 1.







- II -


Host Plants of the Adults

Dqiring the short tin this, in ct ..x been: unr :-ti 'ion
the adiul h.ve been observed in nature feeding on ct re thL' r.nIs
of plants. These include fioli, garden, anid track crops: weeds orna-
mental flowers and. shrubs; wild bushes, trees, and vines. The most 'cP-
men host plants are as follows: Velvetbean, cotton, peanut, ksredeza,
lima bean, sweetrotato, okra, four-o'clock, beautyberry, wild etunia,
myrtle, beggarweed, ragweed, cocklebur, tea,:eed or ironweed, coffee:eed,
wild crotalaria, false-indigo, psrtridge-pea, ground-itch xweei, meyor,
wild morningglory, careless-weed, evening primrose, Ifexican-clover,
styptiC-weed, mintweed, dollar-weed, hawthorn, gallberry, pecan, hack-
berry, black gum, poplar, blackjack oak, camphor, sassafras, wild
grapevine, honeysuckle, greenbrier, kudzu, dewberry, and black-berry.

In the insectary the adults have been forced to feed on grasses,
but their life span was much less than when fed on such rlants as ree-
nut, cotton, and blackberry.

Host Plants of the Larvae

These investigations were not undertaken early enough in 1937 to
permit a thorough check of the host plants of the larvae. Since there
are many other soil insects and animals that cause similar damage, the
list given here includes only the 20 plants on which actual feeding has
been observed. These host plants are as follows: Corn, sugarcane, cow-
pea, chufa, cotton, velvetbean, peanut, cabbage, sweetiotato, collards,
tomato paspalum, careless-weed, smartweed, teaweed or ironweed, carpet
grass, honeysuckle, Mexican-clover, apple, and alligator grass.

Undoubtedly further investigations will greatly expand this
larval host list, as farmers who have had several years of experience
with this insect report that the larvae attack many plants that we have
not yet had an opportunity to observe.

The Effect of Topography and Soil Type on Infestations

In the Florala area infestations occur not only in the cultivated
fields but also in woodland., Tastures, and abandoned farms. The host
range of this insect is such that it is highly probable it can subsist
and develop on wild host plants in pastures and woodland. Scouting
records to December 31, 1937, in the Florala area, show infestation on
5,723 acres of cultivated land and 5,011 acres of noncultivated land.

Soil types seem to have had very little effect, since infestations
of approximately equal intensity occurred on clay, loam, and sandy soils.
To date the greatest damage has occurred on the higher well-drained ror-
tions of the infested fields. tBRARY

Economic Importance of the White-Fringed Beetle

Both the larvae and adults feed on a wide range of plants. As
compared with the damage done by the larvae, the feeding of the ,dults
on plant foliage is of minor importance. Where numerous, the adults





- 12 -


may cause serious injury to gardenand ornamental plants. The larvae
h'mve caused serious damage to numerous field and garden crops. The
dame is exceedingly serious to such crops 'is rot'itoes and peanuts,
where not only the stand is injured but the product is either destroyed
or lowered in grade. It is reasonable to assume that the larvae and
adults will attack many plants that arc widely grown in other sections
but are not grown in the area now icnown to be infested.

If the amount of damage already done in the Florala area can be
used as a valid criterion, it is apparent that the white-fringed beetle,
if allowed to spread, may become a serious pest in many agricultural
regions of the United States. Its large range of host plants renders
control complicated.

Because of the habits of the beetle, it is easily disseminated
through commerce and other artificial means. The eggs are deposited on
many arts of plants that move in commerce and they remain viable for
more than 5 months, hatching when favorable conditions occur. The
larvae can be transported with products which carry smell quantities of
soil. The adults readily attach themselves to many objects that move
in commerce. The importance of the parthenogenetic reproduction of the
white-fringed beetle should not be overlooked, since it is r ossible for
an infestation to be started from only one specimen of any stage. Once
the beetle has established itself in an area, an enormous population may
build up within a shert time, since the lack of flight by the adult re-
duces the possibility of immediate widespread natural dissemination.

Suppressive Measures Employed Against the Beetle
On July 21 a special allotment was made available to the Bureau
of Entomologyn and Plant Quarantine for the control and suppression of
the white-fringed beetle, and the following day approximately 40 Federal
and State inspectors and 200 laborers began 'in active campaign against
the spread of this beetle. within a few days this number was increased
to over 60 inspectors and 400 laborers.

An intensive inspection was made of the Florala area, which was
the only infested area known at that time. After this area was delimited,
inspections were made at numerous ports and commercial centers in the
States of Texas, Louisiana, Mississippi, Alabama, Florida, and G-eorgia.
Localized infestations were found in Laurel, Miss., and vicinity, as well
as in Pensacola, Fla., and New Orleans, La. During scouting activities
beetles of the genus Naupactus, very similar in appearance and habits to
Nauoactus leucoloma, were discovered in Gulfoort, Miss. and vicinity.
No infestations have as yet been found in Georgia and Texas. The States
of Alabama, Florida, Louisiana, and Mississippi have cooperated with the
Bureau by furnishing personnel and other aid.

The infested areas in Alabama, in Mississippi, and in Walton and
0kaloosa Counties, Fla., have been placed under rigid quarantines by
the State authorities, and the movement of all products likely to con-
vey the white-fringed beetle in any stage is restricted.







- 13 -


Approximately 175 miles of barrier ditch were constructed around
ini vi'url infested fields, and an outsi-e barrier tr'en' ro-a..tel
15" mihl s long was conutruot 'rUk1 the .1i-_ti7 L2 n infll t iie
Florala area. The purrcse oif theso trenc es r, tC t tho bqtLs atl
prevent their further spread to new territory.

The first trenches constructed around the fields were of the fur-
row t with sloping finely pulverized siles, like nose com.only used
for chinch but; control, with rost holes 1I5 to 20 feet aj-irt. aily rains
made it impossible to maintain effective furrow-type trenches. Trer.ches
with vertical sides were fund to be much more offuctive during rainy
w7oather. These trenches were approximately 12 inches vido by rl inches
deer. The post holes were 8 to 10 inches deep, with about 2 inches of
loose soil in the bottom. This loose soil served the following two
T purposes: (I) In the event of rain the inrushing water trapped the
beetles in the mud, and (2) if dry weather and sunlight prevailed, the
dust absorbed suff-icient heat to kill the bee-tles. As an adlitional
precaution against the escape of the beetle the rost holes were sprayed
with kerosene twice daily.

The outside barrier trench wos constructed with a tractor plow
pulled by a "35t caterpillar tractor followed by a "trench-conditioner"
pulled by a team of mules. The tractor plow cut a furrow 14 inches wide
by 12.5 inches deep. The "trench-conlitioner" left a finisned trench 16
inches w,;ide by 10.5 inches deer writh vertical, well-packed sides. This
"trench-conditioner" was d(isigned and built by the Bureau of Entemolo~j
and Plant Quarantine specifically for this job in order to eliminate the
large amount of hand labor ordinarily required to make an efficient ver-
tical-side trench. This %.%achine replaced 50 laborers. Post holes were
placed 15 to 20 feet apart in this outside barrier trench. The capacity
of the tractor plow and "trench-conditioner" is approximately 1C miles of
trench for an 8-hour day.

Wherever trench barriers crossed terraces or drains, tran holes
were p.laced in positions to catch the beetles. The trenches, both field
and outside, were patrolled daily, and repairs wore made when necessary.
The adult beetles within the business and residential sections of Florala
and Lockhart, Ala., were hand picked and destroyed.

As a further precaution, the premises around and near lum=beryards,
sawmills, cotton gins, peanut-shelling mills, and other industrial sites
were cleaned of grass and weeds. The railroads cooperatel to the extent
of keeping their yards and rights-of-way throughout the infested area free
of grass and weeds. The counties cooperated by placing trench barriers on
each side of the roads throughout the infested area.

At Laurel, Miss., and Pensacola, Fla., the cities cooperated in
control measures by cleaning the vegetation from vacant lots and alleys
within the infested area and also by erecting trench barriers in the
alleys. The heaviest infested lots were burned over with weed burners.
The railroads cleaned their yards and rights-of-way of weeds, bushes, and
excessive -rass.









I


B


F,


7


0


7Igure 1..-The white-fringed beetle: A, adult beetle, lateral view; B,
adult, dorsal view; C, cluster of eggs; D, full-grown larva lateral
view; E, pupa, ventral view; 1, temporary cusp borne on mandible of
newly emerged adult, lateral view. All greatly enlarged. (Original.)






UNIVERSITY OF FLORIDA

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