Journal of Taiwan Agricultural Research

Author:Shi-Cheng Hung, Kun-Yaw Ho*, and Chien-Chung Chen

Abstract:

    Results of a survey of litchi orchards in Chiayi in 2004 showed that damaged fruits of different varieties of litchi (Litchi chinensis Sonn.) caused by fruit borer Conopomorpha sinensis were 7.5–47% and 88.5% for the areas (in Black-leaf, Nome, 71-3-13, 71-3-15, and 77-S-3 treatments) of pesticide-spray and unspray control, respectively.  Litchi varieties Black-leaf, Nome and 71-3-13 sprayed with Deltamethrin were more resistant to fruit borer, with damaged fruits of 8–16.5% (in Black-leaf), compared to 88.5% for the unsprayed control.  For all surveyed areas, the average of damaged fruits caused by C. sinensis was 29.2% and 60.7% for pesticide-sprayed and unsprayed areas, respectively, whereas the average of damaged fruits caused by the Oriental fruit fly Bactrocera dorsalis was 2.6% and 12.1% for pesticide-sprayed and unsprayed areas, respectively.  Thus, the survey reveals that chemical spray of litchi is effective in reducing fruit damages caused by C. sinensis and B. dorsalis.  Another study showed that C. sinensis caused upto 35.3% of damages of litchi fruits which were ripened and fallen on the ground during the peak period of population increase of this insect in May and June.  Any probing injury of ripening fruits of litchi by fruit borer could create a potential site for B. dorsalis to lay eggs.  Therefore, control of fruit borer may be effective in reducing fruit damages by Oriental fruit fly.  Results of another survey in 2006 and 2007 showed that neither sex pheromone for trapping male insects nor parasitic wasps (Phanerotoma sp.) was effective method for control of fruit borer in litchi orchards.

Key words:Litchi, Conopomorpha sinensis, Bactrocera dorsalis, Damage

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