The abundance of gall fly Cecidochares connexa as biocontrol agent of Chromolaena odorata in several habitat types

Abstract

Chromolaena odorata is one of the weeds which cause a problem in agricultural land, plantations and livestock. Chemical control is considered incapable of controlling the weeds because the sprayed C. odorata stems are still challenging to eradicate. The introduction of the gall fly Cecidochares connexa (Diptera: Tephritidae) from Colombia as a biological control agent was released in 1993 at North Sumatra. This study aimed to know the population level of C. connexa at three different habitats i.e oil palm plantation, agriculture, and urban area. The field study was done by collecting C. odorata for each location then collected weeds observed at laboratory. The data observation were a number of C. odotara, percentage of infected weed and percentage of the adult emerge. The results showed that the oil palm area had the highest number of C. odorata weeds and C. connexa adults compared to agricultural and urban area. Contrastingly, the agricultural area showed the lowest number of the gall fly. There were two parasitoids found in this study, Braconidae sp.1 and Ormyridae sp.1.