Post-Harvest Fungal and Insect Deterioration of Pigeon Pea Seeds and Their Management by Plant Volatiles

Thirty five places of fifteen districts of Eastern Uttar Pradesh were surveyed for collection of stored samples of pigeon pea seeds. In all 20 fungal species of eight genera and two insects (Callosobruchus chinensis and C. maculatus) from pigeon pea seeds were isolated and identified. Maximum number of fungal species was recorded from Ballia district while minimum from Kushinagar. Aspergillus flavus, A. niger, A. ochraceus and A. terreus were dominant and showed higher per cent occurrence. The grains deterioration due to insects was higher in Gorakhpur and Maharajganj districts. Insects caused heavier deterioration than fungi. The essential oils extracted from 25 aromatic plants were screened for their antifungal and insect repellent activities against dominant fungi and both insects respectively at 500 ppm concentration. The oils of Citrus aurantifolia, Mentha arvensis and Ocimum sanctum exhibited absolute toxicity against test fungi while oils of Mentha arvensis, Ocimum sanctum and Vitex negundo showed greater repellency against test insects. These potent oils had promising fungistatic/fungicidal and insecticidal properties. Mentha and Ocimum oils were more potent than Citrus and Vitex oils. Thus, these oils may be used for the management of pigeon pea deterioration during storage after successful in vivo trials.