EVALUATION OF SOME PLANT PRODUCTS FOR THE CONTROL OF THE BRUCHID Callosobruchus subinnotatus PIC. ON BAMBARA GROUNDNUT (Vigna subterranea (L.) Verdcourt

EVALUATION OF SOME PLANT PRODUCTS FOR THE CONTROL OF THE BRUCHID Callosobruchus subinnotatus PIC. ON BAMBARA GROUNDNUT (Vigna subterranea (L.) Verdcourt

Abstract:

Laboratory Evaluations of some plant Products for the Control of adult Callosobruchus subinnotatus Pic. on Bambara groundnut (Vigna subterranea (L.)) Verdc. was undertaken in 2008 and 2009. The objectives of the research were to investigate the effect of the plant products Artemisia annua crude aqueous extract, Aloe vera gel, Gmelina arborea drupe juice and oils from seeds of Moringa oleifera and Mangifera indica on the mortality of C. subinnotatus at three levels of applications of 2 ml/kg, 4 ml/kg and 8 ml/kg. The treatments were compared with Actellic 2% dust at 10 g/kg, Azadirachta indica seed oil at 2 ml/kg as standards and an untreated control. The mode of activity of the plant products, the effect of the treatments on bambara groundnut seed viability, weight, moisture content and progeny emergence were studied under prevailing laboratory conditions. The design of the experiment was completely randomized design repeated three times. Data was analyzed using statistical softwares Microsoft Excel 2003, SPSS 13.0 and SAS 9.0. Results showed treatments with M. oleifera at all three levels of application caused significant mortality of the bruchid from 24 hours post application and compared favourably to the standards at 5% level of significance (Student Newman Keul’s (SNK)) during both years of the trial. Treatments with G. arborea at application rate of 4 ml/kg caused comparable mortality to the standards by the 24th hour in 2008 and 48 hours in 2009. The results also showed the oil of M. oleifera had contact, repellent and some fumigant toxicity and G. arborea had positive repellent toxicity against the bruchid. The treatment A. vera at all three rates of application showed poor performance in causing the mortality of the bruchid up to 72 hours post application as compared to the standards and the treatments were not significantly different from the control in 2008. The gel showed positive contact toxicity 72 hours post treatment that compared favourably to the standards (SNK P= 0.05). Treatments with A. annua and M. indica showed positive fumigant toxicity. However, treatments with A. annua at the rate of 2 ml/kg did not adequately protect the seeds from weight loss and F1 progeny emergence. All the treatments had an effect on the viability of treated seeds causing poor germination. The edible oil M. oleifera can be used as a protectant of bambara groundnut seeds against C. subinnotatus at application rates of 2 ml/kg, however, like many plant oils it should be used for treatments of seeds meant for planting with caution as its physical and chemical property may impair germination. All the plant products showed some biological activity against the bruchids, they can therefore be used for the protection of bambara groundnuts at their effective levels taking advantage of their modes of activity. They can also be incorporated into an effective Integrated Pest Management Programme and future efforts should be geared towards the isolation and standardization of their active ingredients with a view to manufacturing plant based pesticides for use in grain storage by farmers and grain merchants.

EVALUATION OF SOME PLANT PRODUCTS FOR THE CONTROL OF THE BRUCHID Callosobruchus subinnotatus PIC. ON BAMBARA GROUNDNUT (Vigna subterranea (L.) Verdcourt