Effect of organic seed treatments on seed health and quality of cowpea (Vigna unguiculata L.) During Storage

Abstract

Cowpea (Vigna unguiculata L.) is a vital legume crop, but its post-harvest viability is often compromised by deteriorating seed quality, insect damage, and fungal infestations during storage. While chemical protectants are common, their environmental and health risks have driven the search for organic alternatives. This study evaluated the efficacy of nine organic seed treatments on the health and quality of two cowpea varieties, Phule Sonali and Phule Rakhumai, during 300 days of storage under ambient conditions. The treatments included neem leaf powder, neem oil, castor oil, karanj oil, vekhand powder, turmeric powder, citronella oil, and ash, compared against an untreated control. Key parameters assessed were moisture content, germination percentage, root and shoot length, vigor indices, seedling dry weight, electrical conductivity, test weight, seed mycoflora, and pulse beetle (Callosobruchus chinensis) infestation. Results demonstrated that all organic treatments were superior to the control, with neem oil (5 ml/kg) being the most effective. It maintained the lowest moisture content (7.48%), highest germination (77.17%), and superior vigor indices and seedling dry weight. Neem oil also significantly suppressed fungal growth (31.50% mycoflora) and provided the strongest protection against pulse beetle infestation (3.67% at 9 months). Castor oil and neem leaf powder also showed significant, though slightly lesser, benefits. The study concludes that organic seed treatments, particularly neem oil, offer a highly effective, eco-friendly, and economically viable strategy for preserving cowpea seed quality, reducing post-harvest losses, and promoting sustainable agriculture for resource-limited farmers.