Studies on biology and management of pulse beetles callosobruchus maculatus fabricius in chickpea

Abstract

This study focused on understanding the biology and management of pulse beetle (Callosobruchus maculatus) in stored chickpea (Cicer arietinum). The biological observations revealed that the total developmental period of C. maculatus ranged from 32 to 37 days, averaging 35.67 ± 1.81 days. Female beetles exhibited greater longevity (7.68 ± 1.29 days) compared to males (6.65 ± 1.3 days), with an average fecundity of 70.47 ± 3.65 eggs per female. Infestation assessments demonstrated a progressive increase in grain damage and weight loss over time, along with a reduction in seed germination. At the highest infestation level (16 beetle pairs), grain damage reached 74.5%, weight loss escalated to 30.5%, and seed germination declined to 35.2% after 90 days. The efficacy of plant-based powders and oils was tested as alternative management strategies. Among the treatments, black pepper seed powder exhibited the highest adult beetle mortality (84.67%), followed by neem leaf powder (81.97%) and eucalyptus leaf powder (73.24%). Similarly, neem oil was the most effective plant-derived oil, recording 87.47% adult mortality, with karanj oil (79.96%) and castor seed oil (73.21%) also showing significant insecticidal activity. Both plant powders and oils effectively reduced oviposition and adult emergence while improving seed germination. Seeds treated with neem oil achieved the highest germination rate (83.12%), followed by karanj oil (81.25%) and black pepper powder (79.14%). The results highlight the rapid reproduction and severe impact of C. maculatus on stored chickpea, emphasizing the need for effective pest control measures. The study confirms that plant-based powders and oils offer promising eco-friendly alternatives for stored grain protection. Incorporating these botanical treatments into storage management strategies can help preserve seed quality and minimize economic losses associated with pulse beetle infestation. Keywords: Callosobruchus maculatus, chickpea storage, plant-based insecticides, seed viability, grain pr