Assessment of establishment of released parasitoid as biological control agent against the invasive fruit fly

Fruit flies (Bactrocera invadens) are considered the most important and devastating pests of fruits and vegetables in the World due to their potential to cause damage in fruits. In Mozambique, classical biological control is viewed as a potential strategy for the control of the invasive fruit fly. Thus, the parasitoid of eggs, Fopius arisanus (Hymenoptera: Braconidae) was released in 2010 in Mieze, Cabo Delgado province as biological control agent against the invasive fruit fly, B. invadens. However, since its release there has been no information on its establishment and possible impact on the B. invadens population. Therefore, the present study was carried out in Mieze with aim to assess the establishment of the parasitoid, Fopius arisanus. The occurrence of the invasive fruit fly, B. invadens in the study site was evaluated using fruit fly traps baited with Methyl eugenol. Samples of infested fruits of mango, guava and terminalia were collected and reared in the fruit fly laboratory in Pemba, Cabo Delgado province for parasitoids emergence. The results indicated that B. invadens occur at high density with a mean number 18 fruit fly/trap/day. The highest level of damage of 94% was reported from samples of mango fruits. From the samples of fruit collected, 6 adult parasitoids of Fopius arisanus which was released in 2010 corresponding to 0.31% parasitism. The recoveries of Fopius arisanus three years after its release at Mieze indicated that this exotic parasitoid was able to adapt successfully to the local agro-ecological conditions and had established at release site. Evidence of establishment points to the fact that the parasitoid population is likely to increase over the years and have a significant impact on the fruit fly population at the release site.