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William A Overholt - One of the best experts on this subject based on the ideXlab platform.

  • comparative development and population growth of an exotic stemborer Chilo partellus swinhoe and an ecologically similar congener c orichalcociliellus strand lepidoptera crambidae
    International Journal of Tropical Insect Science, 2002
    Co-Authors: Jacob C Mbapila, William A Overholt, Hosea Y Kayumbo
    Abstract:

    Studies were conducted to determine the effect of temperature and diet on the development of Chilo partellus (Swinhoe) and Chilo orichalcociliellus (Strand) (Lepidoptera: Crambidae). Developmental times of C. partellus and C. orichalcociliellus for the egg, larval and egg-adult life stages were inversely related to temperature. The larval developmental period of C. orichalcociliellus reared on artificial diet was longer than the developmental period on natural diet. Chilo partellus had a higher intrinsic rate of natural increase than C. orichalcociliellus at all diet/temperature combinations except natural diet at 31°C.

  • Diapause Termination of Chilo partellus (Swinhoe) and Chilo orichalcociliellus Strand (Lepidoptera: Pyralidae)
    International Journal of Tropical Insect Science, 1999
    Co-Authors: V. C. Ofomata, William A Overholt, R. I. Egwuatu
    Abstract:

    The intensity of diapause of field-collected diapausing larvae of Chilo partellus (Swinhoe) and Chilo orichalcociliellus Strand (Lepidoptera: Pyralidae) was compared in the laboratory at 28 ± 0.5°C under a photoperiod of 12:12 (L:D)h. Chilo partellus terminated diapause faster than C. orichalcociliellus. Mean time to diapause termination was 9.7 days for C. partellus and 14.4 days for C. orichalcociliellus. Male and female C. partellus larvae terminated diapause and adults emerged at the same time, while significant differences were found in diapause termination and in emergence times between male and female C. orichalcociliellus.

  • Comparative evaluation of Cotesia flavipes and C. sesamiae (Hymenoptera : Braconidae) for the management of Chilo partellus (Lepidoptera : Pyralidae) in Kenya
    Bulletin of Entomological Research, 1999
    Co-Authors: Mohamed Nader Said Sallam, William A Overholt, Eunicf Kairu
    Abstract:

    AbstractCotesia flavipes Cameron, a gregarious larval endoparasitoid native to the Indo-Australian region, was imported from Pakistan and released in Kenya in 1993 for management of the exotic stemborer, Chilo partellus (Swinhoe). Recent reports confirmed the successful establishment of the parasitoid in three locations in Kenya and in northern Tanzania. Functional response studies on this parasitoid and an indigenous congener, Cotesia sesamiae (Cameron), indicated that C. flavipes had a higher searching ability and attacked more larvae when Chilo partellus was the host. When a native stemborer, Sesamia calamistis Hampson, was the host, there was no significant difference between numbers attacked by both parasitoids. Numerical response studies showed that Cotesia flavipes produced more total progeny and female progeny per female parasitoid on Chilo partellus than did Cotesia sesamiae. No significant difference in progeny production was detected between the two parasitoids on S. calamistis. Functional and numerical responses tested in the laboratory gave the same ranking of the two parasitoids on the two hosts as in the field. This study suggests that Cotesia flavipes is a more efficient parasitoid and it is anticipated that it will contribute to the control of both exotic and native stemborers in Kenya.

  • Aggressive behaviour of Chilo partellus (Swinhoe) larvae against the parasitoid Cotesia flavipes Cameron.
    International Journal of Tropical Insect Science, 1997
    Co-Authors: Keiji Takasu, William A Overholt
    Abstract:

    Laboratory experiments using a glass tube arena were conducted to determine the effects of aggressive behaviour of the stemborer, Chilo partellus Swinhoe (Lepidoptera: Pyralidae), on oviposition success and mortality of the parasitoid, Cotesia flavipes Cameron (Hymenoptera: Braconidae). On contacting unparasitised hosts, female parasitoids rapidly oviposited and then retreated from the experimental arena. Hosts exhibited no aggressive behaviour prior to oviposition. However, soon after being attacked, host larvae became more aggressive, spitting at and biting the parasitoids. When Co. flavipes females were introduced toward the head of the stemborer, the parasitoids stung the host near the head and were frequently bitten and killed by the hosts. Parasitoids that were introduced to the host from the posterior end of the abdomen, stung the abdomen and were often able to escape from the host without being bitten. Regardless of whether parasitoids were introduced near the head or the abdomen, they were more often killed by older hosts than younger hosts. Parasitised hosts were more aggressive than unparasitised hosts one hour after the initial parasitisation, but not after 24 hours. Larval saliva of Chilo partellus was found to reduce survival of adult female parasitoids. The aggressive behaviour of Ch. partellus was not effective as a self-defense against Co. flavipes, but is likely to be an important mortality factor of Co. flavipes in nature.

Harish Kumar - One of the best experts on this subject based on the ideXlab platform.

  • field resistance in maize cultivars to stem borer Chilo partellus
    Annals of Applied Biology, 1994
    Co-Authors: Harish Kumar
    Abstract:

    Summary The Kenyan maize varieties, Hybrid 511, Hybrid 622, Pwani hybrid, Katumani Composite B, and local populations were evaluated along with the varieties of Multiple Insect-Resistant Tropical (MIRT) pool and experimental varieties from The Maize and Wheat Improvement Centre (CIMMYT), Mexico for resistance to the stem borer, Chilo partellus (Swinhoe). The artificial infestation by first-generation C. partellus on maize during the early whorl stage revealed that the leaf feeding damage, the dead heart formation, and the stem damage on the Kenyan hybrids and populations were significantly greater than on the MIRT varieties. The experimental varieties of CIMMYT were also susceptible to C. partellus. When the maize was infested at anthesis, the Kenyan varieties displayed a moderate level of resistance in terms of stem tunnelling and grain damage by C. partellus. The varieties of Multiple Insect Resistance Tropical pool can be effectively used by the breeders to enhance the resistance of agronomically good, but susceptible, varieties of Kenya.

  • Resistance of Maize to Chilo partellus (Lepidoptera: Pyralidae): Effect of Plant Phenology
    Journal of Economic Entomology, 1993
    Co-Authors: Harish Kumar, Gershon O. Asino
    Abstract:

    Resistance levels of five maize ( Zea mays L.) cultivars differed according to the phenological stage at which they were infested by the stem borer Chilo partellus (Swinhoe). When infested at 3.5 wk after germination, susceptible (control) cultivar ‘Inbred A’ and the test cultivars ‘ER-29SVR’, ‘LS-4’, ‘Nyabwana’, and ‘Across 7844’ showed no dead hearts (drying of the central shoot) and could not be differentiated by the extent of foliar lesions (leaf feeding). However, when infested at 2 wk after germination, differences among the cultivars were clear: only the cultivar ‘ER-29SVR’ showed leaf-feeding resistance and dead heart resistance to C. partellus . The extent of damage in each cultivar was related to the number of late-instar C. partellus remaining in the central whorl.

Eunicf Kairu - One of the best experts on this subject based on the ideXlab platform.

  • Comparative evaluation of Cotesia flavipes and C. sesamiae (Hymenoptera : Braconidae) for the management of Chilo partellus (Lepidoptera : Pyralidae) in Kenya
    Bulletin of Entomological Research, 1999
    Co-Authors: Mohamed Nader Said Sallam, William A Overholt, Eunicf Kairu
    Abstract:

    AbstractCotesia flavipes Cameron, a gregarious larval endoparasitoid native to the Indo-Australian region, was imported from Pakistan and released in Kenya in 1993 for management of the exotic stemborer, Chilo partellus (Swinhoe). Recent reports confirmed the successful establishment of the parasitoid in three locations in Kenya and in northern Tanzania. Functional response studies on this parasitoid and an indigenous congener, Cotesia sesamiae (Cameron), indicated that C. flavipes had a higher searching ability and attacked more larvae when Chilo partellus was the host. When a native stemborer, Sesamia calamistis Hampson, was the host, there was no significant difference between numbers attacked by both parasitoids. Numerical response studies showed that Cotesia flavipes produced more total progeny and female progeny per female parasitoid on Chilo partellus than did Cotesia sesamiae. No significant difference in progeny production was detected between the two parasitoids on S. calamistis. Functional and numerical responses tested in the laboratory gave the same ranking of the two parasitoids on the two hosts as in the field. This study suggests that Cotesia flavipes is a more efficient parasitoid and it is anticipated that it will contribute to the control of both exotic and native stemborers in Kenya.

Mohamed Nader Said Sallam - One of the best experts on this subject based on the ideXlab platform.

  • Comparative evaluation of Cotesia flavipes and C. sesamiae (Hymenoptera : Braconidae) for the management of Chilo partellus (Lepidoptera : Pyralidae) in Kenya
    Bulletin of Entomological Research, 1999
    Co-Authors: Mohamed Nader Said Sallam, William A Overholt, Eunicf Kairu
    Abstract:

    AbstractCotesia flavipes Cameron, a gregarious larval endoparasitoid native to the Indo-Australian region, was imported from Pakistan and released in Kenya in 1993 for management of the exotic stemborer, Chilo partellus (Swinhoe). Recent reports confirmed the successful establishment of the parasitoid in three locations in Kenya and in northern Tanzania. Functional response studies on this parasitoid and an indigenous congener, Cotesia sesamiae (Cameron), indicated that C. flavipes had a higher searching ability and attacked more larvae when Chilo partellus was the host. When a native stemborer, Sesamia calamistis Hampson, was the host, there was no significant difference between numbers attacked by both parasitoids. Numerical response studies showed that Cotesia flavipes produced more total progeny and female progeny per female parasitoid on Chilo partellus than did Cotesia sesamiae. No significant difference in progeny production was detected between the two parasitoids on S. calamistis. Functional and numerical responses tested in the laboratory gave the same ranking of the two parasitoids on the two hosts as in the field. This study suggests that Cotesia flavipes is a more efficient parasitoid and it is anticipated that it will contribute to the control of both exotic and native stemborers in Kenya.

Peeter Päts - One of the best experts on this subject based on the ideXlab platform.