Ability of the Larger Grain Borer, Prostephanus truncatus (Horn) [Coleoptera: Bostrichidae], to Breed on, and Damage Some Tree Species in Ogun State, Nigeria.

OSIPITAN, A. A., LAWAL, O. A, ADEKANMBI, D. I. AND ADEDOKUN, A.O.

ABSTRACT: The study investigated ability of the larger grain borer (LGB), Prostephanus truncatus (Horn) [Coleoptera: Bostrichidae], to breed on, and damage stem cuttings of 15 tree species in Ogun State, Nigeria. Stems of trees, aged 3-4 years, were cut into 4 cm long pieces, dried naturally on the laboratory workbench, and placed in ventilated glass jars infested with 50
adult LGB which were 1-10 days old. Fifty grammes of maize (Zea mays L.) grains similarly infested with 50 adult LGB served as check. All the treatments were replicated four times and arranged in completely randomized design on the laboratory workbench. At 90 days postinfestation, the numbers of eggs, larvae, pupae, adult LGB (dead and living), holes on wood and
maize grains; the weight of wood and maize dust; as well as % loss in weight of maize grains and wood were recorded. The highest mean numbers of eggs (91.0) and living LGB adults (152.0), and the highest % weight loss (79.6) were on maize and the values differed significantly (P<0.05) from those of the wood species. The stem cuttings of Macaranga barteri Muell. Arg. and Anogeisus leiocarpa Guill & Perrowere not damaged by the LGB but those of the remaining 13 species were damaged to varied extents. Delonix regia (Hook) was the only species suitable for LGB breeding. Mortality of adult LOB was 100% on all .stem cuttings excluding D. regia on which mortality was 72%. Concerted efforts at controlling LGB should be evolved to prevent destruction of economic trees by the insect.

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