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
site maintained by the Florida
Cooperative Extension Service.
Copyright 2005, Board of Trustees, University
AGRICULTURAL RESEARCH & EDUCATION CENTER
,jl.i IFAS, University of Florida
LEAFMINER AND TOMATO PINWORM CONTROL'RESEARCF UPDATE
D. J. Schuster, V. H. Waddill, P. H Everett and S.L L.rPoe
.radenton AREC Research Report GC1975-7 November, 1975
The vegetable leafminer, Liriomyza sativae Blanchard and the tomato pinworm,
1'eiferia lycopersicella (Walsingham) are insect pests of major concern to tomato
producers in Florida. Leafminers develop in the mesophyll leaf tissue producing
characteristic serpentine mines. Eggs are oviposited directly into the leaves,
thus protecting hatching larvae from the action of contact insecticides. After
tunneling the leaves, the mature, yellow larvae emerge from the leaves and form
orange puparia on leaves, mulch or soil. Adults emerge to renew the life cycle,
completing development in about 7 to 14 days, depending upon temperature.
Tomato pinworm eggs deposited on leaves or stem are pale yellow when first
oviposited and turn red-orange upon maturation. Newly hatched larvae also feed in
the mesophyll tissue of leaves but produce characteristic blotch mines easily
distinguished from leafminer mines. Early larval developmental stages are light
brot;n but mature larvae appear purple to green. After completing two instars the
larvae leave their mines and may tie adjacent leaves together, form protective
leaf rolls, or bore into stems or fruit (usually at the calyx). Mature larvae
drop from the folds, stems or fruit and pupate in the soil or, in the case of
mulched tomatoes, on the mulch under leaves, or in the soil on the mulch, or in
stake or plant holes. The length of development varies considerably depending
upon temperature but has been reported to average 67 days from egg to adult.
Current information indicates the host range of the pinworm is rather narrow.
As a result, infestations in the field may be reduced by two cultural methods:
1) planting uninfested seedlings, and 2) destroying crop residue and volunteers.
In consideration of reducing infestations or seedlings, insecticides registered
for either leafminers or pinworms were applied singly and in combinations on
greenhouse-grown tomato plants. After six weeks of twice weekly treatments
several compounds appeared very effective (Table 1). Cygon(R) and Lannate(A)
produced seedlings free of pinworm damage although Cygon is ineffective against
pinworms on older plants in the field. Insecticide combinations are not shown
since the results were similar to those of single insecticides. Lannate, Guthion
and Sevin were the most phytotoxic and diazinon, Dibrom and Thiodan the safest
Table 1. The number of tomato seedlings (per 100 sampled) damaged
by pinworm at AREC-Bradenton, Fall 1975.
Material 100 gal. 9/23 10/8 10/21
Check 7.5b' 40.7b 61.2d
Cygon 2.67EC 0.5 0.7a 0.5a O.Oa
Lannate 90S 1.0 0.7a O.Oa O.Oa
Sevin 80WP 1.0 2.7a 3.0a 10.Oc
Thiodan 50WP 1.0 2.7a 0.5a 0.7a
Guthion 50WP 1.0 3.0a 0.2a 0.5a
Dibrom 8EC 1.0 3.0a 3.7a 7.0bc
Diazinon 50WP 1.0 3.7a 0.7a 4.5abc
1Numbers in a column followed by different letters are significantly
different at P = 0.05 (Duncan's Multiple Range Test).
Table 2. Average percentage of tomato seedlings showing
phytotoxicity to insecticide at AREC-Bradenton, Fall
Material Lb ai/100 gal percent damaged
Diazinon 50WP 1.0 0.0
Dibrom 8EC 1.0 0.0
Thiodan 50WP 1.0 1.3
Cygon 2.67EC 0.5 25.0
Lannate 90S 1.0 33.1
Guthion 50~P 1.0 43.8
Sevin 80WP 1.0 45.6
Field trials of weekly insecticide applications against both leafminers and
pinworms indicated that named and experimental insecticides were effective. At
AREC-Homestead (Spring, 1975) three synthetic pyrethroids (FMC-33297, SD-43775
and SD-41706) were effective in reducing pinworm mines and pinworm damaged fruit
(Table 3). This new group of compounds resemble the pyrethrins in their chemical
configuration and margin of safety. Their spectrum of activity, however, is much
broader. The synthetic pyrethroids will probably not be available for use on
tomatoes for at least several years but offer chemical alternatives in years to
come. Bay NTN 9306 is another experimental organo-phosphate insecticide which looks
promising for pinworm control in the future. Fundal, Lannate and Lannate + Vydate
were effective in reducing pinworm mines but the latter were not as effective in
reducing damaged fruit. Fundal belongs to a new class of insecticides and is active
primarily against lepidopterous eggs and is, therefore, less hazardous to biological
control agents. As a result, it should fit into a pest management program where
biological control of pinworms and other pests, including leafminers, is not adverse-
ly affected by spray programs.
Table 3. Tomato pinworm leaf and fruit damage and fruit weight of tomatoes treated
with various insecticides at AREC-Homestead, Spring 1975.
Percent Total fruit
Lb. Mean no. damaged per plot
Material ai/acre mines/leaf fruit (Ibs)
FMC-33297, 25 WP 0.1 0.4a1 21ab 84.4cd
SD-43775, 2.4EC 0.1 0.5a 14a 95.2d
SD-41706, 2.25EC 0.1 1.3a 30b 89.5d
Fundal, 4EC 0.5 1.8a 38b 79.6cd
Bay NTN 9306, 6EC 0.75 4.8ab 76c 63.1bc
1.8L (ea.) 0.45 (ea.) 5.2ab 86cd 73.7cd
Lannate, 1.8EC 0.45 6.6ab 76c 62.8bc
Check -- 20.8cd 90cd 33.8a
Numbers in a column followed by different letters are significantly different at
P = 0.05 (Duncan's Multiple Range Test).
At the ARC-Immokalee (Spring, 1975), various single or combination applications
of insecticides were evaluated for efficacy against both leafminers and pinworms
(Table 4). Phosvel + Thiodan and Lorsban K) were effective against pinworms and
ineffective for leafminers. Lorsban did not produce as great an increase in yield
because it stunted the early growth of tomato plants. Bay NTN 9306 alone and
Phosvel or Lannate in combination with Vydate significantly reduced pinworm-damaged
fruit and were also effective for leafminer control. Other tested compounds were
fairly effective against leafminers but did not equal the best insecticides in
reducing pinworm damage to fruit.
Table 4. Leafmines per 10 trifoliate leaves, pinworm damage and marketable yield
of tomatoes at ARC-Immokalee, Spring 1975.
Lb ai/ Avg. % Pinworm Marketable
Material 100 gal. mines damaged fruit yield (Ibs)
Vydate 1.8EC 0.45 45.7a1 5.9a 136.4cd
Phosvel 45WP +
Vydate 2EC 1.0 57.5ab 5.0a 138.5cd
Vydate 2EC 0.75 58.7ab 15.3b. 102.1b
Monitor 4EC +
Orthene 75S 0.25 60.0ab 16.6b 116.3bcd
Orthene 75S 0.5 60.7ab 12.1b 130.8bcd
Bay NTN 9306 6EC 1.0 64.5ab 3.1a 117.6bcd.
Monitor 4EC 0.5 72.0b 13.9b 110.7bc
Lorsban 4EC 1.0 104.5c 6.0a 108.4bc
Phosvel 45WP + 0.75 +
Thiodan 50HP 0.5 115.Oc 4.4a 144.7d
Check 98.Oc 21.5c 73.6a
1Numbers in a column followed by different letters are
P = 0.05 (Duncan's Multiple Range Test).
significantly different at
At ARC-Immokalee in the Fall of 1974, all tested materials reduced dipterous
leafmines compared to unsprayed plants although Lannate alone was not among the
most effective treatments (Table 5). Yield increases are not demonstrative of
leafminer control but, rather, of control of pinworm and other lepidopterous larvae.
As a result, Lannate (alone and in combination with Vydate), Bay NTN 9306 and FMC
33297 demonstrated control of pinworm and other lepi'-opterous larvae as illustrated
by large increases in yield.
Table 5. Leafmines per 10 trifoliate leaves and marketable
yield of tomato at ARC-Immokalee, Fall 1974.
Lb. Avg. Marketable
Material ai/100 gal mines yield (Ibs)
Vydate 2L +
Lannate 1.8EC 0.45 2.7al 113.2cde
FMC 33297 0.8EC 0.10 3.0a 136.2e
Bay NTN 9306 6EC 1.00 3.2a 114.5cde
Vydate 2.0L 0.75 3.7a 52.2bc
Lannate 1.8L 0.45 14.5b 118.Ode
Check 50.0d 31.Oa
1Numbers in a column followed by different letters are sig-
nificantly different at P = 0.05 (Duncan's Multiple Range
In addition to insecticide evaluations, research has been initiated to identify
genetic resistance in tomatoes to both pinworms and leafminers. Research at AREC-
Bradenton (Summer, 1975) has indicated differences in ovipositional preference of
female tomato pinworm adults for tomato cultivars (Table 6).
Table 6. Oviposition preference of the
tomato pinworm for tomato cultivars
(25 tested) at AREC-Bradenton, Summer
Cultivar No. eggs/plant
Homestead 61 9.3
Indian River 10.8
Although the number of eggs deposited on cultivars such as Homestead 61 is
large, the difference could result in reduced pinworm populations relative to Walter
under an insecticide spray program. In addition, two cultivars, Pearson and Earliana,
have indicated resistance to leafminers under low to moderate leafminer populations
(Table 7). Research is progressing to locate better and more diverse sources of
resistance to leafminers and pinworms to insure a more stable and more effective
means of combatting these pests.
Continuing research is offering alternative and new pesticides for the control
of leafminers and pinworms. In addition, the availability of resistance to these
pests may reduce production costs and the insecticide load on the environment.
Table 7. Average leafmines on 10 trifoliate leaves of tomato
cultivars at AREC-Bradenton, Summer 1975.
Cultivar Total mines
Indian River 17.2ab
Bonny Best 17.5ab
Homestead 24 19.0ab
Homestead 61 26.0b
1Numbers in a column followed by different letters are signifi-
cantly different at P = 0.05 (Duncan's Multiple Range Test).