Indoxacarb (Steward 30WDG): an effective insecticide for the control of Diaphania spp. on bittergourd

The two-location test was conducted to determine the efficacy of foliar-applied Steward 30WDG (indoxacarb) against leaffolder (Diaphania indica) on bittergourd (Momordica charantia). After 5 to 6 sprays at an interval of 7 days, applying a spray volume of 500 liters per hectare, it was determined that indoxacarb at the rate of 30-40 grams a.i./ha was able to effectively protect both leaves and fruits of bittergourd from the feeding damage of leaffolders. The protection offerred by the treatment resulted in yields significantly higher than that from plots treated with lambdacyhalothrin at the rate of 250 g a.i./ha. During the peak of leaffolder infestation, indoxacarb application at the rate of 30 g a.i./ha (3 g product/16 liters) resulted in about 90 percent larval control. This level of control was statistically similar to the 93 percent larval control obtained when a product/16 liters was used. Both rates gave significantly better control than the standard lambda-cyhalothrin 2.5 EC applied at the rate of 250 g a.i./ha (16 ml product/16 liters) which resulted in about 15 percent control. The number of insects on the crop is reflected in the percentage of insect-damaged fruits. Plants treated with indoxacarb at 3 g/16 liters of spray solution had 10-20 percent damaged fruits. This did not differ significantly from the 13-18 percent damaged fruits when 4 grams of the same product was used. Lambdacyhalothrin applied at 16 g/16 liters resulted in 30-55 percent damaged fruits. When no pesticide was applied, 73-74 percent of fruits that developed insect damage. Marketable yield was directly related to the pest control treatments. Unprotected, the crop produced 0.21 to 1.32 tons/ha but when sprayed with indoxacarb at 3 g/16 liters, yield increased to 1.5 to 6.5 tons/ha. Increasing the rate to 4 g/16 liters the yield obtained was 1.7 to 6.4 tons of marketable fruits per hectare. These two yield levels from the treated plots were significantly better than 1.5-2.3 tons per hectare from the crop treated with lambda-cyhalothrin at the rate of 16 ml/16 liter spray solution