Browsing by Author "Mbapila, Jacob Cuthbert"

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    Comparative adaption of cotesia sesamiae (Cameron) hymenoptera braconidae to chilo partellus (Swinhoe) and chilo arichalcociliellus: braconidae to Chilo pertellus (swinhoe) and chilo arichalcociliellus (strand) (Lepidoptera: pyralidae) on the Kenta coast
    (University of Dar es Salaam, 1997) Mbapila, Jacob Cuthbert
    Studies were conducted to determine the effect of temperature and diet on the development of Chilo partellus (Swinhoe) and Chilo orichalcociliellus (Strand) (Lepidoptera: Pyralidae). Developmental times of C. partellus and C. orichalcociliellus for the egg, total larval and egg-adult life stages were inversely related to temperature. Larval developmental period of C. orichalcociliellus reared on artificial diet was slower than the developmental period on natural diet. Pooled head capsule width of both Chilo species indicated some overlap between instars. Chilo partellus had a higher intrinsic rate of natural increase than C. orichalcociliellus Studies on the effect of temperature on development, longevity and population growth of Cotesia flavipes Cameron and Cotesia sesamiae (Cameron) (Hymenoptera: Braconidae) indicated that, the development .of both Cotesia spp. from oviposition to cocoon formation and adult emergence was inversely related to temperature. The longevity of the parasitoids was also inversely related to temperature. Both parasitoids lived longer when moisture and food (agar + honey/ water) were provided . The mean number of females and total adult progeny produced by C. flavipes was, in most cases, higher than C. sesamiae. The intrinsic rate of natural increase of C. flavipes was higher than that of C. sesamiae. Oviposition, development and searching behaviour of C. flavipes and C. sesamiae on aestivating Chilo spp. and non-aestivating C. partellus larvae were investigated. Oviposition experiments indicated that, parasitoids readly accepted aestivating and non- aestivating larvae for oviposition when offered in an artificial laboratory set up. The developmental periods of C. flavipes in aestivating and non-aestivating host larvae were not significantly different (G-test 1.60; P < 0.05). Field cage studies demonstrated that C. flavipes and C. sesamia were unable to locate and parasitize aestivating Chilo spp. larvae in dry maize stems. Parasitization of non-aestivating C. partellus larvae was significantly higher (G-test 7.57; P < 0.05) in cages where C. flavipes was released (26.213) than in cages where C. sesamiae was released (11.323). The population dynamics of C. partellus and other stemborers was investigated in wild sorghum, (Sorghum arundinaceum (Steud) Stapf., napier grass (Pennisetum purpureum Schumach) and guinea grass (Panicum maximum Jacq.) Chilo partellus was the most abundant stemborer species recovered in maize, while C. orichalcociliellus was more abundant in napier and guinea grass. Wild sorghum was the most preferred alternate host among the wild grasses sampled.