Influence of Gender and Age on the Susceptibility of Callosobruchus maculatus (F.) (Coleoptera: Chrysomelidae: Bruchinae) to Some Lethal Botanical Powders

• T.I. Ofuya

  Department of Crop, Soil and Pest Management, The Federal University of Technology, P.M.B. 704 Akure, Nigeria

  Author

• J.E. Idoko

  Department of Crop, Soil and Pest Management, The Federal University of Technology, P.M.B. 704 Akure, Nigeria

  Author

The influence of gender and age on the susceptibility of Callosobruchus maculatus (F.) to six insecticidal plant powders: tobacco snuff (Nicotiana tabacum L.), Ginger rhizome ash (Zingiber officinale L.), neem leaf (Azadirachta indica A. Juss.), Scent leaf (Ocimum gratissimum L., rice husk ash (Oryza sativa L.) and citrus peel (Citrus sinensis (L.) Osbeck, was determined under ambient laboratory conditions (28 ± 4 C and 70 ± 5% RH) in Akure, Nigeria. Each powder was tested at 0.01 and 0.02 g/20 g of grain in plastic plates separately, against 10 males and 10 females that were 1, 2, and 3 days old. There was a control treatment involving no exposure of the insects to any experimental powder. The experiment followed the completely randomized design with three replications. Beetle mortality was observed 24, 48 and 72 hours post exposure. The results showed that females of C. maculatus were generally less susceptible to the insecticidal plant powders than their male counterparts, irrespective of age of the individuals and the dosage of powder. The results also indicated that irrespective of gender and dosage of the plant powders one day old individuals were less susceptible to the plant powders than 2-day and 3-day old individuals. It is recommended that in researches aimed at determining the toxicity of biocides to C. maculatus it may be important to take cognizance of gender of the beetles that are treated, for a more accurate assessment of the efficacy of the biocide. In addition, freshly emerged C. maculatus individuals should be used to determine the true potency of biocides.

1. T.I. Ofuya, Department of Crop, Soil and Pest Management, The Federal University of Technology, P.M.B. 704 Akure, Nigeria

   Department of Crop, Soil and Pest Management, The Federal University of Technology, P.M.B. 704 Akure, Nigeria

2. J.E. Idoko, Department of Crop, Soil and Pest Management, The Federal University of Technology, P.M.B. 704 Akure, Nigeria

   Department of Crop, Soil and Pest Management, The Federal University of Technology, P.M.B. 704 Akure, Nigeria

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