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Group Title: Research Report - University of Florida Agricultural Research and Education Center ; BRA1982-10
Title: research update on the chemical control of the vegetable leafminer on tomatoes
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Permanent Link: http://ufdc.ufl.edu/UF00056138/00001
 Material Information
Title: research update on the chemical control of the vegetable leafminer on tomatoes
Series Title: Research Report - University of Florida Agricultural Research and Education Center ; BRA1982-10
Physical Description: Book
Language: English
Creator: Schuster, David J.
Evertt, P. H.
Dougherty, D. E.
Publisher: Agricultural Research & Education Center, University of Florida, IFAS
Publication Date: 1982
 Record Information
Bibliographic ID: UF00056138
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 62395865

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HISTORIC NOTE


The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
(EDIS)

site maintained by the Florida
Cooperative Extension Service.






Copyright 2005, Board of Trustees, University
of Florida







Agricultural Research & Education Center
University of Florida, IFAS
Bradenton, Florida 33508

Bradenton AREC Research Report BRA1982-10 April, 1982

A RESEARCH UPDATE ON THE CHEMICAL CONTROL OF THE
VEGETABLE LEAFMINER ON TOMATOES1

D. J. Schuster, P. H. Everett2 and
D. E. Dougherty3


The vegetable leafminer, Liriomyza sativae Blanchard, is an insect pest
of major concern to tomato producers in Florida. Leafminers develop in the
mesophyll leaf tissue producing characteristic serpentine mines. Eggs are ovi-
posited directly into the leaves, thus protecting hatching larvae from the action
of contact insecticides. After tunnelling the leaves, the mature, yellow larvae
emerge from the leaves and form yellow or brown puparia on leaves, mulch or soil.
Adults emerge to complete the life cycle in about 14 to 21 days, depending upon
temperature.

Numerous experiments have been conducted in the field to investigate the
relative efficacy of various insecticides to control L. sativae. During the spring
of 1977, insecticides were applied weekly in a grower's field to 'Walter' tomatoes
beginning about 10 days before the first harvest (Table 1). Leafminer damage was
severe at that time, averaging about 25% defoliation. Nevertheless, significant
reductions in the numbers of leafmines and percent defoliation were observed on
plants sprayed with Ambush and Bolstar. Although Vydate and Pydrin reduced the
number of leafmines 2 weeks after spraying was initiated, control, as measured by
defoliation, was not good after 6 weeks.

In another grower field test in the fall of 1977, fruiting 'Walter' tomato
plants were sprayed 4 times with insecticides at weekly intervals (Table 2).
Significant reductions in the numbers of total and active leafmines were observed
with Pydrin, Ambush, Vydate, Monitor, Pounce and Bolstar. Cygon did not reduce
leafminer damage.

In a final experiment in a commercial field in the spring of 1978, 'Walter'
tomato plants were sprayed weekly beginning about 6 weeks before the first harvest.
Some insecticides were not applied every week due to label restrictions in the
spray interval before harvest. Only Ambush and Pounce significantly reduced the
total number of leafmines after 6 applications (Table 3). However, Monitor had
not been applied within 2 weeks of the evaluation due to a 14-day harvest interval
restriction in effect at the time of the experiment. Azodrin had been applied only
once because of its 21-day harvest interval.

Two insecticide experiments were completed on un-staked (ground) tomatoes
at the ARC-Immokalee during the spring of 1979 and 1981. Sprays were applied
weekly beginning 3-4 weeks after transplanting and continued to harvest.

iMention of a pesticide does not constitute or imply a recommendation or endorsement
by the authors or the University of Florida.
2Associate Professor of Entomology (AREC-Bradenton, 5007-60th Street East, Bradenton,
FL 33508) and Professor of Soil Chemistry (ARC-Immokalee, Rt. 1, Box 2G, Immokalee,
FL 33934), respectively.
3Former Assistant professor (ARC-Immokalee), presently with BASF Wyandotte, Inc.,
Raleigh, NC.









After 2 applications in the first experiment, significantly fewer leafmines were
counted on foliage sprayed with Ambush, Monitor (1.0 lb a.i./100 gal) or Monitor
plus Thiodan relative to foliage sprayed with water. In the second experiment,
fewest leafmines were observed on foliage sprayed with L-676,863 although signifi-
cantly fewer leafmines were also observed on foliage sprayed with SD 52618 (0.50
lb a.i./l00 gal) compared to foliage sprayed with water. Significantly more leaf-
mines were counted on.foliage sprayed with Penncap-M at 1.0 lb a.i./l00 gal than were
counted on foliage sprayed with any other treatment.

The pyrethroids, Ambush and Pounce, appear to have the greatest potential
relative to other chemicals in several experiments. This was true whether
relatively sparse (fall 1977, spring 1978) or dense (spring 1977) populations
of L. sativae were present. However, these pyrethroids appear to have lost their
effectiveness in controlling a closely related leafminer, L. trifolii (Burgess),
on celery (Dr. Gary L. Leibee, personal communication). Monitor gave significant
control of L. sativae compared to unsprayed plants whenever evaluations were made
within 1 week of spraying. Although Vydate reduced the number of leafmines on
tomato plants sampled in the 1977 experiments, % defoliation was not reduced when
the leafminer population was heavy (spring 1977). None of the other chemicals
registered for leafminer control on tomatoes (Diazinon, Dibrom, Azodrin, Parathion,
Penncap-M, Toxaphene, Guthion, Trithion, Cygon, Ethion, Phosphamidon and Dylox)
resulted in fewer leafmines relative to the water check. New compounds (L-676,863
and SD 52618) have demonstrated potential in reducing leafminer damage on tomatoes
and hold promise for future use.


Table 1. Control of the vegetable leafminer on tomato plants sprayed weekly with
insecticides (Manatee Co.). Spring 1977.
No. leafmines/
Treatment Lb. a.i./l00 gal 10 trifoliates1 defoliation2
Ambush 2EC 0.1 28.1a0 43.8a
Bolstar 6EC 1.0 31.Oa 52.6b
Vydate 2L 1.0 36.8ab 89.Od
Pydrin 2.4EC 0.1 69.Ob 66.1c
Check 106.8c 90.2d
!Counts were made 2 weeks after the initial spray. A trifoliate is 3 terminal
leaflets.
2Defoliation was estimated 6 weeks after the initial spray.
3Means within columns followed by the same letter are not significantly different
at the P=0.05 level, Duncan's new multiple range test.


Table 2. Control of the vegetable leafminer on tomato plants after 4 weekly
insecticidal sprays (Hillsborough Co.). Fall 1977.
No. leafmines/10 trifoliates-
Treatment Lb. a.i./100 gal Total Active
Pydrin 2.4EC 0.1 5.5a- 0.5ab
Ambush 2EC 0.1 6.5a O.Oa
Vydate 2L 1.0 8.0a 1.2ab
Monitor 4EC 1.0 8.5a O.Oa
Pounce 3.2EC 0.1 10.2a 2.0ab
Bolstar 6EC 1.0 1.Oba 0.2a
Cygon 4EC 0.5 28.2b 8.5c
Check 26.5b 6.5c
IA trifoliate is 3 terminal leaflets. not significantly different
2Means within columns followed by the same letter are no
at the P=0.05 level, Duncan's new multiple range test.













Table 3. Control of the vegetable leafminer on tomato plants sprayed weekly1 with
insecticides (Manatee Co.). Spring 1978.
No. leafmines/5 trifoliatesl
Treatment Lb. a.i./100 gal Total Active

Ambush 2EC 0.10 29.5a2 5.5a
Pounce 3.2EC 0.10 32.5a 10.0ab
Pydrin 2.4EC 0.10 45.2ab 7.5ab
Monitor 4EC 1.00 51.2abc 11.5abcd
Diazinon 50WP 0.25 60.2bcd 14.5abcd
Orthene 75SP 1.00 61.5bcd 1l.Tabcd
Bolstar 6EC 1.00 63.0bcd 14.2abcd
Dibrom 8EC 1.00 63.2bcd 14.2abcd
Azodrin 5EC 1.00 63.5bcd 15.0abcd
Parathion 8EC 1.00 64.2bcd 18.2abcd
Toxaphene 8EC 1.00 65.0bcd 11.2abc
Lannate 90SP 0.45 66.2bcd 16.2abcd
Guthion 50WP 0.50 67.0bcd 16.5abcd
Thiodan 2EC 1.00 76.7cd 25.7d
Trithion 8EC 1.00 78.2cd 24.5cd
Cygon 4EC 0.50 78.7cd 16.5abcd
Ethion 4EC 0.50 82.7d 25.7d
Phosphamidon 8EC 0.50 82.7d 20.7bcd
Dylox 80SP 1.00 84.Od 21.2bcd
Dipel WP 1.00 85.2d 22.5cd
Check (Water) -- 71.2bcd 14.0abcd

1Counts were made after 6 applications except for Azodrin and Dylox which were
sprayed once and Monitor, Parathion, Toxaphene, and Phosphamidon which were
sprayed 3 times because of harvest intervals. A trifoliate is 3 terminal leaflets.
2Means followed by the same letter are not significantly different at the P=0.05
level, Duncan's new multiple range test.













Table 4. Control of the vegetable leafminer on tomato plants after 2 weekly
insecticidal sprays (ARC-Immokalee). Spring 1979.
No. leafmines/10
Treatment Lb. a.i./100 gal trifoliates1

Ambush 2EC 0.10 34.2a2
Monitor 4EC 1.00 39.0a
Monitor 4EC + Thiodan 2EC 0.75 + 1.00 42.5a
Monitor 4EC + Isotox Lindane 25WP 0.75 + 0.375 48.2ab
Monitor 4EC + Phosphamidon 8EC 0.75 + 0.50 49.7ab
Monitor 4EC 0.50 53.2ab
Monitor 4EC + Dibrom 8EC 0.75 + 1.00 55.0ab
Isotox Lindane 25WP 0.375 55.7ab
Phosphamidon 8EC 0.50 59.5ab
Check (Water) --- 73.2b

A trifoliate is 3 terminal leaflets.
2Means followed by the same letter are not significantly different at the P=0.05
level, Duncan's new multiple range test.


Table 5. Control of the vegetable leafminer on tomato plants after 8 weekly
insecticidal sprays (ARC-Immokalee). Spring 1981.
No. leafmines/10
Treatment Lb. a.i./100 gal trifoliatesI

L-676,863 0.04SL 0.04 O.Oa2
L-676,863 0.04SL 0.02 O.Oa
L-676,863 0.04SL 0.01 0.3a
SD 52618 85WP 1.00 12.3ab
SD 52618 85WP 0.50 18.7bc
SD 52618 85WP 0.25 29.0bc
Ammo 2.5EC 0.075 25.7bc
Ammo 2.5EC 0.05 28.2bc
Ammo 2.5EC 0.04 29.0bc
Pydrin 2.4EC 0.10 29.0bc
Lorsban 4EC 0.75 31.2c
Lorsban 4EC 1.00 33.5c
Penncap-M 2EC 0.50 36.7c
Penncap-M 2EC 1.00 53.7d
Check (Water) --- 35.Oc


A trifoliate is 3 terminal leaflets.
2Means followed by the same letter are not
level, Duncan's new multiple range test.


significantly different at the P=0.05




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