Host Susceptibility and Pest Status of Fruit Flies (Diptera: Tephritidae) Attacking Cucurbits in Two Agroecological Zones of Cameroon, Central Africa

Abstract

Cucurbits are among the most valuable food crops in various developing countries of sub-Saharan Africa. The development of integrated strategies in their pest management is limited by lack of information on fruit losses, especially by tephritids and their pest status on crops. Thus, based on fruit damage rates and infestation rates, cucurbits' susceptibility to tephritids was assessed in Yaounde and Koutaba, two localities situated in different agroecological zones in Southern Cameroon. From systematic samplings in trap plots, 6009 damaged fruits from nine cucurbit species were collected weekly and bimonthly and incubated during 2009–2011. Fruit losses, which were evaluated at 36.73±1.90%atYaounde and 37.08 ± 3.22 % at Koutaba, did not vary in relation to locality. Losses due to tephritids were more important on Sechium edule and Cucurbita moschata at Yaounde and on S. edule, Citrullus lanatus (watermelon), Cucumis melo (sweet melon), Cucumis sativus and Cucurbita moschata at Koutaba. At each site, Cucumis melo var. agrestis was the less susceptible species. With the exception of S. edule, developing fruits were more susceptible to tephritids as 80% of positive fruits weighed less than 100 g. Moreover, four tephritids emerged from fruits; Dacus bivittatus and Dacus ciliatus appeared to be the major pests and Dacus vertebratus a minor pest. Pest status of Dacus punctatifrons depends on border plants. Also, D. ciliatus exhibited preference for Cucurbita moschata and D. bivittatus for S. edule and Cucumeropsis mannii. Our findings provide useful data for the conception of Integrated Pest Management (IPM) strategies against tephritids.