Developmental Biology Of Fruit Fly (Diptera: Tephritidae) Species Attacking Cucurbits

ABSTRACT

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

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be studied. The studies will add information on rearing, forecasting and ecological

management of fruit flies.