Evaluation of Toxicity of Some Plant Materials Against the Bruchid (Callosobruchus maculatus (F.) (Coleoptera: Chrysomelidae) on Mung Bean (Vigna radiata (L.) Wilczek) Seeds in Storage

Abstract

to determine the toxicity of powders of Piper guineense fruits, Dennittia tripetala fruits Allium sativum bulbs, Zingiber officinale rhizomes against the cowpea seed bruchid Callosobruchus maculatus (F.) (Coleoptera : Chrysomelidae) on stored mung bean (Vigna radiata (L.)Wilczek) seeds. The experimental design was a 4 x 5 factorial fitted into Completely Randomized Design (CRD) with three replications. The rates for the different powders were 0.0, 0.5,1.0,1.5, 2.0g admixed with 20 g of mung bean seeds placed in plastic containers. The effect of the treatments were assessed on insect mortality at 48 and 96 hours, oviposition 7 days post treatment, adult emergence on 28 days after infestation, and seed viability test at the expiration of the experiment (42 days post treatment). The results showed that plant powders were effective in controlling insect infestation by recording significantly higher mortality, reduction in the number of eggs laid, and suppression of the development and emergence of adult progenies from the treated mung bean seeds compared with the control. Piper guineense provided the best protection for stored mung bean at 2.0 g/20 g compared with the other treatments, followed by Allium sativum. Dennittia tripetala and Zingiber officinale were almost the same in their performance. Plant materials did not affect the viability of the seeds. The results obtained suggest that the plant materials possess insecticidal properties and can be utilized in protecting stored mung bean from C. maculatus infestation since they are environmental friendly, cheaper than synthetic insecticides and safer for humans. Mung bean (Vigna radiata (L.) Wilczek) is one of the most important short season, summer growing legumes grown widely throughout the tropics and subtropics [1]. Mung bean cultivars [2] were a potential source of essential fatty acids, antioxidants, minerals and proteins. The seeds and sprouts are excellent examples of functional foods that lower the risk of various diseases [3]. The seeds and sprouts have health promoting effects in addition to their nutritive value [4]. Today there is an increasing interest in western countries in the sprouting of seeds as consumers demand minimally processed, additive-free, more natural, nutritional and healthy foods. The seeds may be milled or ground into flour for making noodles, breads and soups. In rural areas, the immature green pods are also used as vegetable. Mung bean stalks, leaves and husks constitute a significant proportion of livestock feed. After picking of the pods, the whole plant may be ploughed in the soil to improve fertility. Like other legumes, mung bean is attacked by field to stored insect pests. Insect pest can significantly reduce mung bean profitability, reducing both yield and seed quality. In order to ensure food security for the citizenry, surplus grains are properly preserved in storage. Stored grains in addition to serving as a source of domestic food supply throughout the year, serve a as means to generate revenue for the farming families....

Developmental impairment and Oviposition deterrence in Callosobruchus maculatus (Fabricius) infesting Vigna radiata (L.Wilczeck) upon treatment with five different plant products

“…Various plant products such as leaf powders, oils and extracts of varied kinds of plants are known to possess insecticidal properties (15) . Different powders of plants have been researched widely, to find the plant which was most lethal to C. maculatus, thereby providing complete protection to the pulses while being non-toxic to the consumers (16)(17)(18) .…”