CARIBBEAN FOOD CROPS SOCIETY

THIRTEENTH ANNUAL MEETING ST. AUGUSTINE TRINIDAD, W. I. JULY 6-12,1975

PUBLISHED WITH THE COOPERATION OF THE UNIVERSITY OF PUERTO RICO MAYAGUEZ CAMPUS 1980

VOLUME XIII THE PINWORM - A NEW PEST FOR JAMAICA

C. HENRY, B. RUDERT, L. HOLLAND Orange River Experiment Station, Jamaica.

SUMMARY

The Tomato Pinworm - lycopersicella, was recently identified for the first time in Jamaica. A description of the pest and its life history is given along with a discussion of problems concerning its control.

INTRODUCTION

A small pest that can cause big problems for tomato growers was recently identified for the first time in Jamaica. The pest, the toma- to pinworm, (Fam. ), has been found in the past year at four government agricultural stations; Lawrence field, Bodies, Caenwood and Orange River. This pest feeds on members of the plant family . Serious outbreaks have occurred mainly on tomato, both in the field and seedbed, but it has been found on and as well. It has been found on the Solanaceous weed, Sola- num americanum var. nodiflorum and reported to be on Susumber, So- lanum torvum.

DESCRIPTION AND LIFE HISTORY

The trouble is caused by the larvae which feed on the leaves, flowers and fruits of the tomato plant. The larvae are small, about 1/8" - V4" long, green with purple spots along the side and spines that can best be seen with a magnifying glass.

There are four larval instar stages, the first two as leaf miners and the latter two as leaf tiers and rollers. The first signs of da- mage on tomato are often mistaken for tomato leaf miner, Agromyza sp., as the newly emerged larvae burrow between the leaf surfaces. As the larvae grow older, they spin silk, tie up leaves and cause large necro- tic, blotchy areas to occur, often totally destroying the leaf surfaces of the plant. During the latter stages of growth they may also burrow into the fruit, tunnel to the core and leave small necrotic pinholes where they enter, hence the name tomato pinworm.

The larvae pupates in the soil around the plant and the adult that emerges is about '4' ' long, grey or tan in colour. This moth then lays its eggs on the upper and lower leaf surfaces of the plant where

1T9 they hatch into the destructive larvae. The entire life cycle of the in- sect is long (Table 1) and between seven or eight generations per year can be expected (Poe, 1973).

TABLE 1. Duration of the developmentall stages of the tomato pinworm (Elmore and Holland, 1943).

Developmental Stage Number of days required Average Minimum

Egg - Incubation 8.9 4 Leaf Mining 11.5 5 Leaf Folding 9.5 3 Prepupae 6.9 1 Pupae 30.2 15 Egg to Adult 67.0 28

The importance of this caterpillar as a newly introduced pest to Jamaica cannot be over-emphasized. One can only speculate on its entry to Jamaica and how long it has been here. The insect is in , , Haiti and .

CONTROL

Florida tomato growers have always suffered from light out- breaks of the pest but since 1970 the pest has become more and more severe there, warranting the attention of agricultural specialists (Wolfen- barger, 1974). They link this increase in outbreaks to the ban on DDT which previously kept the pest in check.

When the larva burrows under the leaf surface and ties up the leaves, it is protected from sprays and chemicals. It has been reported that systemic chemicals, such as Lebaycid and Rogor. alone are not effective and are less effective than contact chemicals (Poe, 1974).

The Key to successful chemical control is to leave a toxic chemical residue on the plant at all times. The larvae utilize more than one feeding site in their lifetime and it is when they abandon one feeding site to go to another, that they are susceptible. For this reason and the long life of the larvae, it is hard to control the pest with single spray. It is estimated that at least 6 to 9 weekly spray applications are needed to eradicate the pest once it is established in a crop (Poe, 1974).

180 In January 1975, the pinwom appeared in severe proportions on a stand of young tomato plants at Orange River Agricultural Station. A number of plants were completely defoliated and the entire planting was in danger. The pest had occured on previous tomato plantings but mostly on older, fruiting plants. A simple spray trail was planned and Phosvel, Surecide, Sumithion, Dipterex, Cygon, Basudin and Le- baycid were sprayed at normal rates on the infested tomato plants. Three days after spraying it was noted that the larval mortality was 0% in both treated and untreated plots) as a result of this two more sprays were applied at weekly intervals and the dosage rate doubled each time. Again, no appreciable larval mortality was observed. These results "are in accordance with Poe's findings (1974) that short term mortality is hard to achieve and a long time period is required to control the pest when it is at high population levels and firmly established on the plants. A sample of Lannate was then obtained and applied over all plots. This effectively killed all piriworm larvae and the pest was never a problem again in this stand of tomatoes. Since this time, whenever the pest has shown up in the seedbed or field, Lannate has effectively eradicated all pinworm larvae present and in a statistical spray trial being conducted at the moment, Lannate is giving better results than other chemicals and the control. Poe (1973, 1974) and Wolfenbarger (1974) did not experience this quick knock-down effect with Lannate in Florida.

Proper sanitation methods should also be observed. Old crop residues can harbor the pest and reinfest fields and seedbeds. Regular tillage in the field can be important as this disrupts the pupation site.

CONCLUSIONS

The tomato pinworm, Keiferia lycopersicella, which was iden- tified for the first time in Jamaica is potentially a very serious pest. Be- cause of its protected feeding habits and long life cycle, it is hard to con- trol with most conventional chemicals. However, Lannate has proven to be very effective and has a quick knock-down effect when used at normal rates.

REFERENCES

Elmore, J.C. and A.F. Howland. (1943). Life History and Control of the Tomato Pinworm. USDA Tech. Bull. 841. 30 p.

181 Poe, S.L. (1973). Tomato Pinworm, Keiferia lycopersicella (Walshing- ham) (: Gelechiidae) in Florida, Florida Entomo- logy Circular No. 131.

Poe, S.L. (1974). Comparison of Single and Combined Insecticides for Control of Tomato Pinworm in Florida, Florida Agric. Exp. Stn. Journal Series No. 5477

Wolfenbarger, D.O. (1974). Small Pest Cause Big Trouble for Tomato Growers, Sunshine State Agricultural Research Report, July 1974.

Identification and verification of the pest as Keiferia lycopersicella was made by Dr. Tom Farr of the Institute of Jamaica and by the Smith- sonian Institute, Washington D.C., USA, January 1975.

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