Fruit flies are among the major pests of cucurbits in many parts of Tanzania. Studies
on fruit flies (Diptera: Tephritidae) attacking cucurbit in Morogoro were conducted
at Sokoine University of Agriculture (SUA). Objectives of the studies were: to
compare incidences and infestation rates of selected fruit fly species in different stages
of cucumber fruit, to establish duration and determine survival of immature stages of
Bactrocera cucurbitae in selected cucurbitaceous hosts. Cucurbit fruit fly species
incidences and infestation rates were determined from fruit flies emerging from fruits
harvested in crop museum using standard procedures. Duration and survival of B.
cucurbitae immature stages were established and determined respectively by observing
B. cucurbitae immature stages development in watermelon, cucumber and pumpkin at
20, 25 and 30oC using environmental chamber. High incidence (0.75) was observed in
immature cucumber fruits with B. cucurbitae while low (0.16) was in mature cucumber
with Dacus frontalis. High infestation rate (120 flies/kg fruits) was observed in
immature fruits by B. cucurbitae and low (5 flies/kg fruits) was in mature fruits by
D. frontalis. Long duration (16.23 days) of B. cucurbitae was recorded in pupal
stage at 20oC while short duration (0.99 days) was in egg stage at 30oC. High
(97.72%) and low (76.03%) survivals of B. cucurbitae was recorded in egg stage at
30oC and 20oC respectively. Among targeted fruit flies B. cucurbitae had high
incidences and infestation rates in cucumber fruit stages. Duration and survival of
B. cucurbitae immature stages decreased and increased respectively with increase in
temperature. Further studies on incidence and infestation of fruit flies in different
cucurbitaceous hosts, agro ecological zones and seasons should be conducted.
Relationships on biology of D. bivittatus and D. frontalis with temperature need to
be studied. The studies will add information on rearing, forecasting and ecological
management of fruit flies.
Commission of Science and Technology (COSTECH)