Field Release and Impact of Cecidochares connexa (Macquart) (Diptera:Tephritidae) on Chromolaena odorata (L.) King and Robinson

Abstract

Field release of the gall fly, Cecidochares connexa (Macquart) (Diptera: Tephritidae) introduced from Indonesia into India in 2002 was made on naturally growing C. odorata (L.) King and Robinson at two locations in Bangalore during July-October, 2005 using different field release methods. Following establishment, the gall fly was observed lo spread to a distance of one kilometer at GKVK and two kilometer at Tataguni village in northeastern direction by the end of second year after release. The gall numbers encountered by an individual in ten minutes, search steadily increased from 2.5 to 98.3 at GKVK and from 1.6 to 156 at Tataguni village. There was 11.61 and 16.72 per cent reduction in plant height. 30 and 60 days after oviposition in galled plants over control. There was significant reduction in number of branches per plant (35.62%), number of panicles per plant (45.43%), number of capitula per panicle (12.07%) and number of seeds per head (10.89%) in galled plants over control in individual oviposition method. In mass cage method, 40.84, 36.48 and 55.42 per cent reduction in plant height, 30, 60 and 120 days after oviposition in galled plants over control was recorded. There was significant reduction in number of branches per plant (65.56%), number of panicles per plant (48.44%) and number of capitula per panicle (58.98%) in galled plants over control.