Development of an IPM Program for Leaf-footed Bug, Leptoglossus australis in Pohnpei, Federated States of Micronesia
Cucurbit vegetables are grown on about 52,000 acres in Micronesia, primarily to increase rural incomes, reduce dependency on imported products and diversify and improve local diets to address a vitamin A deficiency. The Leaf-Footed Bug is a major pest of cucurbits (cucumber, bittermelon, melon, pumpkin and zucchini) as well as beans, tomato, eggplant, citrus and guava. Frequent applications of broad-spectrum pesticides (malathion, carbaryl and endosulfan) are used to control the Leaf-Footed Bug although recommendations have not been reviewed in the past 12 years. An egg parasitoid, Gyron sp., was introduced from Guam in 1992 and seemed to be working but farmers returned to their broad-spectrum pesticides. This project will develop an IPM program for the Leaf-Footed bug using biological control agents, crop sanitation, crop rotation, low risk pesticides and other tactics. One intriguing possibility is the use of pesticide-impregnated nets for trellising of cucumber plants. They will then test the program and promote it to farmers, extension agents and consultants through training workshops, field demonstrations, brochures, radio and television.
Project goals and objectives
1. The identification of an appropriate and sustainable approach for control of the leaf-footed bug.
2. The reduction of the risks to farmers' and consumers' health and to the environment in general through an IPM program which consists of a range of complimentary control methods, and involves a minimal use of selective and less hazardous chemicals only.
The cooperators held on-farm trials to develop an IPM program for the Leaf-Footed bug on cucurbits. Treatments for two cultivars ("Fountain" and "Merry Swallow") included various types of mulch applied to soil and the bagging of developing fruit. Each trial was replicated three times at three distinct sites between April 2001 and May 2002. Complete fertilizer, chicken manure and organic-based foliar sprays were applied to all sites and treatments and mechanical weed control was used every two weeks. However, leaf-footed bugs appeared in high numbers only during the first trial and appeared to be kept in check by the egg parasitoid, Gyron, for the duration of the study. The relative absence of the Leaf-footed bug revealed the importance of other pests that affect cucumber production including caterpillars, aphids, cutworms, grasshoppers and katydids. In addition to these pests, the Truk Island stink bug, Megymenum affine, was found for the first time and has the potential to further affect cucumber production in the state. Low yields were observed in all trials at all sites except at the Pohnlangas Pohnpei State Agriculture Farm. Overall, the variety "Merry Swallow," which is preferred by farmers and consumers, produced 50 percent higher yields in weight and 35 percent more fruit than the variety "Fountain." Mulching with coconut fronds increased yields by 26 percent over no mulch and 50 percent over mulching with grass. Likewise, coconut frond mulch produced 14 percent more fruit than no mulch and 40 percent more fruit than grass mulch. Bagging of fruit resulted in a 15 percent increase in yield and 14 percent more marketable fruit.