Conopomorpha sinensis(Lepidoptera: Gracillariidae) and Its Larval Parasitoids

Abstract

Litchi fruit borrer, Concopomopha sinensis (Lepidoptera : Gracillaridae) is the most important insect pest of lychee and longan. Most lychee and longan growing areas in Northern Thailand have been seriously attacked by C. sinensis. Crop loss assessment and their insect parasitioids were investigated at Chiaangrai Horticultural Reserch Center during outbreak season from April to August, 1995-1996. It revealed that fruit shedding of lychee wee usually occurred 40-90% after fruit set throughout the season under fruit bagging and no bagging conditions. Fruit drop in lychee and decreased in longan, and also provided protection from the infestation of C. sinensi. Fruit drop of lychee was increased with no bagging due to litchi fruit borer, fruit crack and fruit browning disease which re the main effects of yield reduction. Harvested fruit of longn were 61.82% in 1995 and 56.28% in 1996 under bagging conditions. But there wee only 22.55% and 23.06% of lychee fruit that had been haarvested. It was found that under no bgging conditions, 8.86% of lychee and 1.03% of longan were infested by C. sinensis in 1995. Similarly, in 1996 there were 8.52% and 1.58% in lychee and longan respectively. It is clear that bagging can be used to protect fruit damaged by C. sinensis. However, 6.25% of fruit browning were obviously seen in lychee under bagging conditions. This never happens in longan.
Mature fruit of longqan and lychee were randomly harvested. Apparently 19.4% of lychee were not infested by fruit borer whereas 65.41% wee destroyed. 8.4% of fruit had brownskin. Moreover 6.74% of lychee were simultaneously damaged by fruit browning disease and fruit borer. 89.89% of harvested fruit of longan were not attaqcked but 9.93% were contaminated by fruit borer.
Insect parasitoids of C. sinensis wee observed. Five species of larval pqarasitoids have been found, all of them are solitary ectoparasitoids. Three species of braconic were Phanerotoma sp., Colastes sp. and Pholestesor sp. Another two icheumonids were identified as Goryphus sp. and Paraphylax sp. Infested fruit fal lby C. sinensis were parsitised 49.07%. There were only 4.18% of parasitism on lychee and 7.28% on longan leaves.๔