EFFICACY OF INSECT GROWTH REGULATORS AGAINST LITCHI FRUIT BORER, Conopomorpha sinensis

Abstract

The litchi fruit borer, Conopomorpha sinensis (Lepidoptera: Gracillariidae) is one of the most destructive and major pest of litchi fruits. The experiment was carried out at three different locations to develop bio rational management strategy using insect growth regulators (IGRs) against the litchi fruit borer. Namely emamectin benzoate, buprofezin, lufenuron, lufenuron + emamectin benzoate and abamectin were applied to evaluate the toxicity effects on C. sinensis. The effectiveness of IGRs against the C. sinensis was evaluated on the basis of fruit damage (%), healthy fruit (%), diameter (mm) and length (mm) of fruit, fallen fruit (%), harvested healthy and damage fruit (%) and total number of larvae of fallen fruits in different litchi orchards. The study revealed that buprofezin showed the lowest (13.32%) fruit damage followed by lufenuron + emamectin benzoate (15.44%), abamectin, emamectin benzoate and lufenuron by C. sinensis which was statistically significant over control. However, the highest number of healthy fruits (86.71%) was found in buprofezin treatment followed by lufenuron + emamectin benzoate, abamectin, emamectin benzoate and lufenuron. The mean highest length and diameter of fruits was found in buprofezin 25.68 and 17.78 mm, respectively. The highest damaged fallen fruits were found (11.29%) in control whereas the lowest (2.12%) in buprofezin treatment. The number of larvae on fallen fruits showed that buprofezin and control were significantly different. Increased number of larvae in fallen fruits was found in the control treatment. Number of C. sinensis adult moth in light traps was increased in mid-season in all of three orchards and statistically insignificant. Nutrient quality of litchi fruits was not affected by the application of IGRs. Therefore, buprofezin can be used to manage the litchi fruit borer in organic litchi orchards.