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Title: Florida Entomologist
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Creator: Florida Entomological Society
Publisher: Florida Entomological Society
Place of Publication: Winter Haven, Fla.
Publication Date: 1939
Copyright Date: 1917
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Subject: Florida Entomological Society
Entomology -- Periodicals
Insects -- Florida
Insects -- Florida -- Periodicals
Insects -- Periodicals
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Florida Entomologist

Official Organ of the Florida Entomological Society


VOL. XXII


APRIL, 1939


TWO NEW THYSANOPTERA FROM MEXICO
J. R. WATSON
Heterothrips cuernavacae n. sp.
MACROPTEROUS FEMALE:--General body color brown. Head, prothorax,
femora and tibiae and most of antennae and sides of abdominal segments
8-10 darkest, raw amber (Ridgeway, Plate III).


Fig. 1.-Heterothrip cuernavacae nov. sp. Head and prothorax
9 holotype. (J. R. P. Del.)


Pterothorax lighter and suffused with orange hypodermal pigment,
abdomen lighter still, segments 1 to 4 and 8 gray brown and suffused
with yellow hypodermal pigment, segments 6 and 7 darker and lacking
the hypodermal pigment so that the abdomen in the type and one paratype
has a distinct banded appearance, segments 8 to 10 darker especially along
the sides. In one paratype the abdomen is uniformly colored. Antennal
segment III with yellow pedicel, gradually shading to brown toward apex,
also apex of IV lighter. All tarsi yellow tipped with brown, fore tibiae
tinted with yellow, especially along the inner margin; bases of middle
and hind femora lighter.
Fore wings uniform light brown except a small, oval colorless area
in basal fourth.


No. 2










THE FLORIDA ENTOMOLOGIST


Head 11/2 times as wide as long, widest behind the eyes. Cheeks
strongly bulging behind the eyes, bearing two colorless spines about 12
microns long. Dorsum striated, two lines being especially heavy.
Eyes tapering to a point apically, subtriangular in outline, pilose,
facets large.
Ocelli yellow, posterior pair opposite posterior third of eyes and
contiguous with their margins, a series of three or four minute bristles
near and close to the posterior margins of the
eyes. Antennae 21/2 times as long as head.
oProthorax about 1%/ times as wide (in-
cluding coxae) as long. Dorsal surface nearly
o smooth. A stout, brown spine at each posterior
Single about 26 microns long. Pterothorax a
trifle wider than prothorax. Metathorax with
sides converging posteriorally.
Fig. 2Heterothrip ueForewings with about 22 bristles on fore
Fig. 2.-Heterothrips cuerna-
vacae. Right half 7th abdominal vein and 18 on hind and 23 on costal border.
.tePrr holotype. (Drawn by Fringe short on basal third but beyond that
abruptly lengthened. Abdominal segments
provided with three pairs of bristles on dorsal surface. These become
progressively longer to the 7th or 8th segment, where the median pair,
which are longest, project well beyond the border of the segments, but
diminish in length and stoutness on 9th and 10th segments.
Posterior segments bordered by combs of hairs of approximately equal
length whose bases are not at all coalesced into plates.
Measurements of type. Total body length 1.4 mm. Head, length
.10 mm., width .15 mm., prothorax, length .16 mm., width .23 mm.; ptero-
thorax, width .24 mm..; abdomen, width .28 mm. Antennae, total length
.26 mm. Segments, length (width): I, 19(30); II, 33(24); III, 51(21);
IV, 37(22) ; V, 28(21); VI, 29(19) ; VII, 23(13) ; VIII, 20(12) ; IX, 11(9)
microns.
MALE:--Considerably smaller than female.
Color almost uniform brown, only tarsi; fore tibiae (except margins),
base of antennal segment III, apex of IV and in some paratypes apex of II,
brownish yellow. Pterothorax and abdomen somewhat lighter than head
and prothorax. Testes dark brown. Hypodermal pigment of female largely
absent.
Fore femora considerably enlarged, more than half as wide as long.
Measurements of type. Total length .87 mm. Head, length .07 mm., width
.21 mm.; pterothorax, width .22 mm., abdomen greatest width .14 mm.
Antennae, total length .27 mm. Segment, length (width): I, 23(26); II,
30(24); III, 51(21); IV, 42(21); V, 33(18); VI, 33(17); VII, 26(12);
VIII, 21(12); IX, 21(7) microns.
Length of paratypes varies from .84 mm. to .97 mm.; length of an-
tennal segment II from 28 to 35 microns, III from 45 to 51, IV from 33
to 43, V from 23 to 33, VI from 26 to 35.

Described from three females and eight males collected from
an unknown composite at Cuernavaca, Mexico, August 22, 1938.
Type in author's collection. Paratypes in U. S. National Museum.










VOL. XXII-No. 2


Arpediothrips mexicanus n. sp.
MICROPTEROUS FEMALE:-Length about 1 mm. Body almost uniformly
light brown (clay color-Ridgeway Pl. XXIX). Fore tibiae, distal half of
middle and hind tibiae, all tarsi and antennal segments 3-5 lighter. Head
appreciably wider than long; widest across the cheeks. Cheeks arched,
narrowing to base of the slightly bulging eyes and to the base of the mouth
cone. Vertex finely but distinctly striated. Postocular bristles distinct,
about 11 microns long. Ocelli pale but bordered by bright red crescents,
widely separated, posterior pair situated posterior to the middle of eyes
and close to their margins but not touching; anterior well back of apex.
Mouth cone long, reaching the mesosternum.
Eyes dark red, rather coarsely faceted.
Prothorax wider than long, sides almost straight and parallel. The
long spines at posterior angles about 23 microns long. Those at anterior
angles and the others at posterior angles minute.
Mesothorax considerably wider than prothorax, sides sharply arched.
Metathorax narrower with sides straight but converging posteriorly. Wings
very short, not reaching the second abdominal segment. Abdomen thick
and heavy. Posterior angles of the posterior segments carry conspicuous
brown bristles. Those of segment 8 almost thorn-like, 29 microns long.
Those on segment 9 also heavy, 56 microns long. Terminal bristles 58
microns.





















Fig. 3.-Arpediothrips mexicanus nov. sp.
Head and prothorax holotype. (J. R. P. Del.)

Measurements of type female: Body length 1.02 mm. Head, length
.14 mm., greatest width .17 mm. Prothorax, length .12 mm., greatest width
(including coxae) .17 mm. Mesothorax, greatest width (near middle)
.21 mm. Metathorax, greatest width (at base) .19 mm. Abdomen greatest
width .26 mm. Antennae, total length .25 mm. Segments, length (width):
I, 21(29); II, 36(26); III, 41(20); IV, 42(16); V, 37(16); VI, 47(16);
VII, 9(7); VIII, 12(5) microns.









THE FLORIDA ENTOMOLOGIST


Some of the paratypes vary somewhat widely from these measurements
given above. Total length varies from .9 mm. to 1.14 mm. Head length
in one is only .12 mm. Prothorax length varies from .09 mm. to .14 mm.
Length of antennal segment I from 12 to 23 microns. II is only 31 microns
long in one; IV varies from 31 to 42 microns; VI from 42 to 60 microns.
In all, the head is wider than the prothorax.
MALE (Micropterous) :-Somewhat lighter in color than the female.
Testacles deep brown. Smaller, the paratype only .816 mm. long.
Measurements (of type): Total body length .97 mm. Head, length
.12 mm., width .15 mm.; prothorax, length .103 mm., width .15 mm.; meso-
thorax, length .19 mm.; metathorax, length .17 mm. Abdomen, width
.18 mm. Antennae .234 mm. Segments, length (width): I, 19(28); II,
30(23); III, 41(16); IV, 35(14); V, 35(14); VI, 44(16); VII, 7(12);
VIII, 12(5) microns.
In the paratype III is 44 microns long and VI only 33.

Described from eleven females and two males taken from
under the leaf sheaths of a Yucca in the state of Neuvo Leon,
Mexico, north of Monterey on August 7, 1938.
These have been compared with paratypes of the type species
A. mojave Hood from California. This species is much darker
in color, a more sturdy insect (mojave is slender) ; head pro-
portionally narrower, and the prothorax much narrower. The
bristles much more sturdy and darker, especially those on the
posterior abdominal segments.



ARTHUR P. JACOT

We are advised, just as we go to press, of the death on
March 24th at New Haven, Connecticut, of Arthur P. Jacot.
Readers of the FLORIDA ENTOMOLOGIST will recall numerous
articles of his on beetle mites which have been published in
our journal over a period of several years. These articles in-
cluded descriptions of numerous new species or varieties as well
as many notes on the taxonomy and distribution of species
already described. Most of these were collected by entomolo-
gists of the Experiment Station, especially the late Edgar
Grossman, although Mr. Jacot himself made one trip to Florida
where he made firm friends of all of us. His untimely death
is a great shock. We hope in an early number of the ENTO-
MOLOGIST to be able to give a more extended account of his
life and w6rk.









U'he


FLORIDA ENTOMOLOGIST
Official Organ of the Florida Entomological Society
Gainesville, Florida

VOL. XXII APRIL, 1939 No. 2

J. R. WATSON, Gainesville-.............--........---...................... Editor
E. W. BERGER, Gainesville ..-..--.......-.........--......Associate Editor
J. W. WILSON, Belle Glade.....-..........-...................Business Manager
Issued once every three months. Free to all members of the
Society.
Subscription price to non-members is $1.00 per year in ad-
vance; 35 cents per copy.


THE PHYSIOLOGICAL EFFECTS OF MINERAL OILS
ON CITRUS1
L. W. ZIEGLER
Consulting Entomologist, Winter Haven, Fla.
INTRODUCTION
In the use of any spray material for control of plant pests
the deleterious effects of such materials on the plant itself must
be recognized. The studies along this avenue of research were
conducted during an investigation leading to the manufacture
of an oil emulsion for citrus use. It is through the courtesy of
the Haines City Citrus Growers Association, for whom the work
was done, that the presentation of this paper is made possible.
The percentage of actual oil used in these experiments was
necessarily held at a high level in order to properly evaluate
the differences in physiological effects. Deficiencies in soil mois-
ture during the period under discussion have probably also
accentuated the results. It should be noted here that no damage
has resulted from the widespread use of emulsions similar to
those of Experiment No. 2 at concentrations of from 1% to
1.3% actual oil during the summer months of 1938.

TYPES OF OIL DAMAGE
Primary Physiological Effects
Emulsions of the heavier distillates have been in use since
the turn of the century. Since that time the literature on the
iPaper read before the December 1938 meeting of the Fla. Ent. Soc.









THE FLORIDA ENTOMOLOGIST


subject of damage resulting from the use of the oil emulsion
has become extensive. The following references cannot be con-
sidered complete, but only as showing the trend of the work.
Volck (1)2 and Knight, Chamberlin and Samuels (2) have
shown that oil penetration is greatest in those areas where
stomata are located but not necessarily confined to those areas.
Knight and Cleveland (3) have reported that the amount of
penetration is associated with the angle of contact, which ac-
counts for the greater penetration on old foliage, especially
where the cutin has been destroyed by insects, abrasions or
ordinary wear and tear.
Others (4) has recorded the drop of large percentages of
old leaves starting about three days following oil treatment.
Other types of damage were noted in lesser degrees. Gray and
DeOng (5) have tabulated the "chronic" injuries to citrus due
to applications of heavy oils which leave oil films on leaves or
twigs for days or weeks. Twigs and even larger limbs are
stunted or killed. Fully matured leaves, especially if senile,
are more susceptible to injury from neutral oils, while young
leaves are more susceptible to injury from oils of lower sul-
phonation.
DeOng, Knight and Chamberlin (6) have shown that oils
of from 51% to 60% sulphonation resulted in heavier defolia-
tion and twig death than did neutral white oils of 98% sul-
phonation. They have also called attention to the temperature
factor. DeOng (7) has further suggested that apparently the
1st or 2nd treatment with sulfuric acid or sulfur dioxide re-
moves the. parts dangerous to plants and insects. Smith (8)
has shown that the amount of leaf drop following oil applica-
tions to citrus is correlated with the amount of oil deposited,
and increases with higher viscosities and lower sulphonations.
DeOng, Knight and Chamberlin (6) have described the char-
acteristic effects following the use of neutral white oils as: more
or less heavy leaf drop principally of senile or semi-senile leaves;
drop of tree-ripe fruit; inhibition of normal color in lemons;
drop of green Valencia oranges during humid weather and re-
tardation of ripening.
Magness and Burroughs (9) have found that an oil film on
the surface of stored apples may have a distinct effect on gase-
ous exchange. The evolution of carbon dioxide to oxygen was
reduced, but analysis of the air in the inner cellular spaces

2Refers to literature cited on page 28.









VOL. XXII-No. 2


showed an increase in the ratio of carbon dioxide to oxygen.
Burroughs (10) has noted a reduction in the amount of starch
produced in apple leaves that seem to have been arrested in
their growth by an application of an oil spray.
Kelley (11) has found that both saturated and unsaturated
oils retarded transpiration on deciduous fruits, when applied to
the lower leaf surfaces where the stomata are located.
Secondary Physiological Effects
Shamel and Pomeroy (12) have shown a correlation between
number of leaves on Valencia trees and the fruit sizes. In other
papers: Shamel, Pomeroy and Care (13) and Shamel and Pom-
eroy (14) have shown similar relationships in Navel oranges
and Marsh grapefruit. Magness, Overley and Luce (15) have
shown correlations between leaf area and size of crop on apples
and pears.
Spuler, Overley and Green (16) have stated that oil sprays,
particularly those of high viscosity, cause metabolic disturbances
in the foliage (of apples) which is reflected in decreased size
and color of fruit. The extent to which these disturbances de-
crease the size and color of fruit is dependent on the load of
fruit on the trees, the soil moisture and the variety of fruit.
Fudge (17) has shown that while magnesium deficiencies
"bronze" foliage of grapefruit and cause excessive defoliation
under heavy cropping, the succeeding alternation of bearing
results, not because of a magnesium deficiency, but principally
because of a limited and inefficient leaf area.
EXPERIMENT NO. 1
A tank mix application was made on February 25th to Valen-
cia trees, using an oil of 70 seconds viscosity and 83% U. R. at
a concentration of 12%% actual oil. Application was thorough,
inside and outside, with use of two nozzle guns. This tank mix
depended chiefly on the agitation of the paddles for stability.
Such agitation was found to be slightly deficient with the result
that the last portion left in the spray tank contained a higher
percentage of actual oil than did the first portion. Therefore
the first group of trees (nine) received a lesser percentage of
oil than did the last group (five).
There was general growth of a good green color, averaging
five inches in length at the time of application. Bloom was heavy
with some fruit set, some blossoms open and some unopened
blossom buds. A 33 F. temperature was recorded the night









THE FLORIDA ENTOMOLOGIST


following the application with minimum temperatures from 460
to 64' during the following week (maximums 76 to 840).
Primary Oil Damage Symptoms
General shadowing of both old and new foliage occurred,
with marginal burn of a slight degree appearing on new foliage
after several days. The distal portions of the petals of the un-
opened bloom spread apart to allow the pistil to protrude and
brown spots appeared on the outer surface of the petals. Despite
these abnormalities, the blossoms opened normally. There was
some drop of mature leaves, being greatest in the second group
of trees but no counts were made. At the end of 10 days 39%
of the young set fruit on the treated trees was yellow in color
or shed; while only 18.3% showed these conditions on the un-
treated trees.
The most outstanding effect of this application was the drop
of tree-ripe fruit of the 1937 crop. On April 22nd (56 days
after application) a count of all fruit on the ground showed an
average of 52.6 for the sprayed trees against 5.4 for the un-
treated. This drop was greatest in the second group of treated
trees (Table No. 1).
Fruit crops were recorded as the number of fruit which
could be observed from the ground to a six-foot level while
slowly walking around the trees. This has proven to be a very
reliable comparative criterion. The average of two counts
(April 22nd and September 3rd) revealed 51.4 fruit per treated
tree as against 76.7 per untreated tree. This decrease in fruit
crop is correlated with the percentage of young set fruit paled
or dropped by the oil application and is considered a direct
effect of the application.
Secondary Physiological Effects
On September 3rd the treated fruit averaged 6.65 cm. in
diameter while the untreated averaged 6.7 cm. From the work
of Shamel and Pomeroy (12) the fruit on the treated trees
would be expected to be smaller in size than those on the un-
treated trees due to loss of foliage resulting from oil applica-
tion. That this did not occur is considered to be due to the
fact that the oil also dropped a percentage of the fruit crop
and probably in proportion to leaf drop; the leaf-fruit ratio
remaining undisturbed.
June growth appeared more rapidly on the treated trees.
On June 1st 21.75% of the spring growth terminals on the








VOL. XXII-No. 2


treated trees showed burst buds, while only 7.2% showed the
same condition on the untreated.
Due to dry conditions during the spring of this year (1938)
there was an exceedingly heavy June bloom. On September 3rd
there was an average of 18.9 June bloom fruit on the treated
trees as against 26.8 on the untreated.

EXPERIMENT NO. 2
On May 12th adjacent Valencia trees were treated with an
oil of 70 seconds viscosity and 83% U. R. at 1/%% concentra-
tion and emulsified with succeedingly larger amounts of the
same material in the proportions of 1, 2 and 4. Thus the actual
deposit of oil on the tree surfaces was succeedingly decreased.
The spray was applied by the author as a thorough outside
coverage and a similar inside coverage as afforded by the force
of 500 pounds pressure, with the use of a 6-nozzle gun. Mini-
mum temperatures during the week following application varied
from 570 to 720 F. (Max. 87-940.)
At the time of the application the fruit averaged 3.7 cm.
in diameter with slight variations between trees. All trees were
in a thrifty condition, spring growth hardening and no wilt in
spite of lack of rain. The crop varied as follows: Tree No. 1,
light, 20 fruit; No. 2, medium, 70 fruit; No. 3, heavy, 195 fruit;
No. 4, light, 29 fruit; No. 5, light, 15 fruit; and No. 5-II, heavy.
Trees Nos. 1, 5 and 5-II received no oil. Tree No. 2 received
an emulsion containing 23 cc. emulsifier per gallon; No. 3 one
containing 46 cc.; and No. 4 one containing 92 cc.

Symptoms of Oil Damage
The mature leaves of the 1937 fall flush began to drop 24
hours after treatment and continued a little over one-half month.
This drop was recorded by counting the number of leaves on
the ground from the "drip" of the tree outward to the square
of the tree at two to three day intervals. The average drop for
the untreated trees was 104.5; while for the treated trees it
was 543. This drop was in approximate proportion to the tree
size and not in relation to amount of emulsifier (Table No. 2).
The heavy drop of mature leaves would be expected as shown
by the work of Knight and Cleveland (3) which indicates that
oil penetration is greatest on old foliage and that this penetra-
tion cannot be controlled to any great extent. It should be con-
sidered that the deposit of oil was heavy in all cases and probably









THE FLORIDA ENTOMOLOGIST


exceeded the minimum requirements necessary for mature leaf
drop in even the most "tight" formula used.
Drop of spring fruit began a few days after treatment and
continued for about a month (Table No. 2). As the amount
of emulsifier was increased, the droppage was decreased.
Drop of spring foliage was tabulated by counting the number
of leaves on 50 spring growth terminals and the number of fresh
leaf scars indicating dropped leaves. Two counts were averaged
(May 17 and June 1), showing a decreasing amount of droppage
as the emulsifier was increased (Table No. 2).
All sprayed trees showed very definite shadowing of leaves
and fruit. On the day following the application 99% of the
spring leaves and 100% of the spring fruit showed shadow.
This shadow appeared to be slightly more continuous with the
lower amounts of emulsifier. No shadow was evident on the
untreated trees. Even 141 days later, on September 30th, a
few fruit on the treated trees showed slight shadowing.
There was no burn evident on foliage and only one fruit
(on Tree No. 3) showed burn.
Secondary Physiological Effects
As noted above, Shamel and Pomeroy (12), Magness, Overley
and Luce (15), Fudge (17), any condition which drops large
percentages of foliage will have a resultant effect on the physio-
logical balance of the tree. Since the droppage of foliage of
1937 fall growth was more nearly correlated to the size of the
trees and number of leaves present, it would be presumed that
secondary physiological effects would be nearly constant for all
treated trees. This apparently is the case.
The untreated trees showed an average fruit diameter on
August 27th of 6.69 cm., while the treated trees averaged 6.1 cm.
The fruit size was inversely proportional to size of crop (Table
No. 4). The variations between sizes on the treated trees were
constant with the variations between sizes on the untreated.
Thus, the ratio between 5-II and 5 (untreated) is similar to that
between 3 and 4 (treated).
On the first of June counts of 50 spring growth terminals
showed an average of 25% with burst buds on untreated trees;
while the average was 70% on the treated trees, with no sig-
nificant difference between trees (Table No. 3).
The June bloom crop averaged 3.3 fruit for the treated trees,
with 33 fruit for the untreated (Table No. 4).









VOL. XXII-No. 2


SUMMARY
Applications of high concentrations of mineral oils exert a
direct effect on Valencia trees. This effect is most pronounced
in the droppage of tree-ripe fruit and mature leaves due to their
lowered surface tension allowing for greater penetration of oil.
Drop of immature leaves and fruit was in no case as heavy
as that of mature leaves and fruit. The surface tension is
higher on these parts and the resistance to penetration greater.
On such surfaces the minimum amount of oil required for abscis-
sion is greater. The effect of varying amounts of oil deposition
as influenced by the emulsifier would, therefore, be more marked.
This has been shown.

Secondary Physiological Effects
The loss of large numbers of leaves following these heavy
applications of oil resulted in three definite physiological re-
sponses. The size of immature fruit was retarded, except where
the reduction of crop was approximately proportional to reduc-
tion in leaf area. The number of fruit borne in the succeeding
crop was reduced. The subsequent flush of growth was accel-
erated. A fourth condition, killing of wood, is sometimes brought
about either directly due to oil penetration or as a secondary
effect should new growth fail to appear after drop of leaves.
In the latter case, sap exchange is interrupted which results
in the collapse of the wood cells.

CONCLUSIONS
The value of oil applications for the control of scale pests
is well-established. The damages outlined in this paper were
brought about by applications of oil of high concentrations at
periods of the year which are normally considered untimely for
such applications. On the other hand, the same types of emul-
sions were used throughout the year on hundreds of acres of
groves under commercial conditions without damage and with
excellent scale control.
The insecticidal and phytocidal properties of mineral oils
are closely correlated. Therefore emulsions of these oils must
be so timed in their applications to allow maximum deposit with-
out detrimental plant reaction and minimum deposit for thorough
pest control. Emulsifying an oil in such a manner as to reduce
the oil deposit upon application to the plant does not answer the
question.










THE FLORIDA ENTOMOLOGIST


The premature droppage of foliage, from any cause whatso-
ever, must be regarded as a detrimental factor in commercial
fruit production. Fruit production is the function of foliage.
Acceleration in appearance of a growth flush when due to de-
creased or inefficient foliage conditions signifies a return of the
plant to a vegetative state; a physiological response toward
maintaining equilibrium of value to the commercial orchardist
only when the motivating force has been unavoidable.

LITERATURE CITED
1. VOLCK, W. H. Spraying with distillates. Cal. AES Bul. 153: 1-31,
1903.
2. KNIGHT, HUGH, J. C. CHAMBERLIN and C. D. SAMUELS. On some
limiting factors in the use of saturated petroleum oils as insecti-
cides. Plant Phys. 4: 299-321, 1929.
3. KNIGHT, HUGH, and C. R. CLEVELAND. Recent developments in oil
sprays. Jour. Econ. Ent. 27: 269-289, 1934.
4. YOTHERS, W. W. Spraying for the control of insects and mites at-
tacking citrus trees in Florida. Farm Bul. 933, 1918.
5. GRAY, GEO. P., and E. R. DEONG. Laboratory and field tests of Cali-
fornia petroleum insecticides. Ind. Eng. Chem. 18: 175-180, 1925.
6. DEONG, E. R., HUGH KNIGHT and J. C. CHAMBERLIN. A preliminary
study of petroleum oil as an insecticide for citrus trees. Hilgardia
2: 351-384, 1927.
7. DEONG, E. R. Present trend of oil sprays. Jour. Econ. Ent. 24:
978-985, 1931.
8. SMITH, RALPH H. The tank-mixture method of using oil sprays.
Cal. AES Bul. 527: 1-86, 1932.
9. MAGNESS, J. R., and A. M. BURROUGHS. Apple Storage Investigations.
Marble Lab., Canton, Pa., Rept. 1921-22.
10. BURROUGHS, A. M. Effects of oil sprays on fruit trees. Proc. Amer.
Soc. Hort. Sci. 1923: 269-277.
11. KELLEY, VICTOR W. Effects of certain hydrocarbon oils on the trans-
piration rate of some deciduous tree fruits. Ill. AES Bul. 353, 1930.
12. SHAMEL, A. D., and C. S. POMEROY. Relation of amount of foliage
to fruit size in Valencia oranges. Cal. Citro. Mar. 1934.
13. SHAMEL, A. D., C. S. POMEROY and R. E. CARE. Relation of foliage
to fruit size in Washington Navel oranges. Cal. Citro. Sept. 1933.
14. SHAMEL, A. D., and C. S. POMEROY. Relation of foliage to fruit size
in Marsh grapefruit. Cal. Citro. Sept. 1934.
15. MAGNESS, J. R., F. L. OVERLEY and W. A. LUCE. Relation of foliage
to fruit size and quantity of apples and pears. Wash. AES Bul.
249, 1931.
16. SPULER, ANTHONY, F. L. OVERLEY and E. L. GREEN. Oil sprays for
summer use. Wash. AES Bul. 252, 1931.
17. FUDGE, B. R. The relation of magnesium deficiency in leaves of grape-
fruit to yield and chemical composition of fruit. (In press. Bulletin
Series, Fla. AES.)











VOL. XXII-No. 2


TABLE NO. 1-EXPERIMENT NO. 1-COMPARISON OF TREATED AND
UNTREATED TREES.


Date
Checked
1938

2/26

2/28




3/7


4/22





6/1


Treated Trees
All First Last
Trees Nine Five

Present Present Presei


Condition


Leaf Shadow ........................-

Marginal burn on young
foliage -...............................

Young set of fruit pale in
color ............ ......................

Young set fruit light in
color or dropped ................

Average drop of tree-ripe
fruit (per tree) .................

Average number of 1938
spring fruit per tree
(ground to six-foot level)

Average percentage of
spring growth terminals
showing burst buds of
June flush ......................-....

Average number of 1938
spring fruit per tree
(ground to six-foot level)

Average size of 1938 spring
fruit in diameter ..............

Average number of 1938
June fruit per tree
(ground to six-foot level)


Slight







33.4


57.6







65.8





24.9


Slight


Un-
treated
STrees

it Absent


None


36.0%


I 18.3%


87.2 5.4


29.8 65.3



7.2


35.8 88.1


6.7 cm.


8.0 26.8


TABLE NO. 2-EXPERIMENT NO. 2-DROP OF LEAVES AND FRUIT
FOLLOWING OIL APPLICATION.


Mature
Leaves
(number)

46

373

456

800

163


Spring
Foliage
%

4.43

7.23

4.46

3.99

2.01


Spring Fruit
Number Percentage*


0.0

44.3

24.1

17.2

13.3


Slight


58.0%


39.0%


52.6


47.6



21.75


55.1


6.65 cm.


18.9


Tree
No.

1

2

3

4

5


Amount
Emulsifier

Check

23 cc.

46 cc.

92 cc.

Check


*Based on crop from ground to six-foot level.











30 THE FLORIDA ENTOMOLOGIST

TABLE NO. 3-EXPERIMENT NO. 2-PERCENTAGE OF SPRING TERMINALS
SHOWING BURST BUDS OF JUNE GROWTH JUNE 1, 1938.


Amount Emulsifier


Check

23 cc.

46 cc.
92 cc.
Check


Percentage


38.0

72.0

66.0

72.0

12.0


TABLE NO. 4-EXPERIMENT NO. 2-CROPPING.


Amount
Emulsifier


Check

23 cc.

46 cc.

92 cc.

Check
Check


Size of Crops


Spring Crop
5/12/38 | 8/27/38


*5-II Check is a further untreated tree which had a
was counted for cropping conditions to show comparison
also had a heavy crop.


June Crop
8/27/38

37
1

8

1

17

45


Average Size
Spring Fruit
8/27/38

6.78
6.19

5.97

6.13

6.75
6.53


heavy crop of fruit and which
with No. 3 treated tree which


Printing for All Purposes

Carefully Executed

Delivered on Time



Pepper Printing Company

Gainesville, Florida


Tree No.


1

2

3

4
5


Tree
No.


1

2

3

4

5

5-II*









VOL. XXII-No. 2


SOME ECOLOGICAL NOTES ON THE LUBBERLY LOCUST-
Romalea micropter Beauv.1
By J. R. WATSON and H. E. BRATLEY
The lubberly locust, though generally distributed over Flor-
ida and other southeastern states, has for several years been
particularly troublesome in the vicinity of farms where nar-
cissus was being grown. Complaints from farmers in these
regions induced the writers to undertake a study of the relation-
ship between this insect and the bulb farms. Large numbers
of adults were imprisoned in cages in Gainesville in June, 1938,
fed liberally and allowed to lay eggs in the soil. Egg-laying in
these cages was concluded in early August. The first young
hoppers appeared on March 14, 1939. The same week the first
nymphs were observed in a bulb farm at Penney Farms. For
the first few hours after hatching the nymphs are of a reddish
brown color so that newly hatched ones are easily identified.
They remain in colonies close to the egg mass from which they
hatched for several days, which makes them still more conspicu-
ous and enables one to determine the place of oviposition. It
was found that they were not coming from the bulb fields nor
any field which was plowed or cultivated after June. They were
hatching on ditch banks, roadsides and in a field which was
planted to early corn in 1938 but not cultivated after June.
They were very abundant in a cleared field which had never
been plowed but had a loose, sandy, well drained soil. On the
other hand none were observed in the more compact soils of
the undisturbed "flat woods" or pinelands.
A most remarkable migration from these situations into the
narcissus fields was observed. The nymphs moved in columns
from adjoining fields in some cases five or six hundred feet
away, straight towards the narcissus. On March 24th fifteen
of these columns of migrating nymphs were observed in two-
tenths of a mile, crossing an asphalt road. They were moving
against the wind.
]Contribution from the Department of Entomology, Florida Agricul-
tural Experiment Station.


A THIRD OF A CENTURY OF EXPERIENCE

W. W. OTHERS
Consulting Entomologist
457 Boone Street, Orlando, Fla.
Advisory Work Confined to Citrus
Citrus Literature Bought and Sold Without Profit
REPORTS AND APPRAISALS OF CITRUS PROPERTY




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