Strengthening vegetable defense mechanisms against insect-pests and diseases through neem-enriched organic manures and beneficial soil microbe inoculation

Abstract

The overuse of inorganic fertilizers and pesticides for vegetable production has degraded soil fertility, reduced populations of beneficial microorganisms, and weakened the natural resistance of crops to biotic stress. As a result, crops have become more vulnerable to insect-pests and diseases, while human health and the environment also face significant risks. To overcome these challenges, adopting eco-friendly alternatives such as compost made from neem leaves, vermicompost, and utilising plant growth-promoting microorganisms is crucial. These sustainable practices not only enhance crop growth and yield but also naturally control insectpests and diseases, promoting both environmental sustainability and human well-being. A long-term field experiment was conducted from 2019–20 to 2023–24 at the College of Agriculture, Sumerpur-Pali, to evaluate the effects of six different combinations of chemical fertilizers and neem-enriched organic manures, along with the inoculation of plant growth-promoting microorganisms (PGPMs), on the induction of systemic resistance in various vegetable crops. The results revealed that substituting chemical fertilizers with neem-enriched organic manure, combined with PGPMs inoculation, significantly enhanced the plants’ natural defense mechanisms and reduced the incidence of insect-pests and diseases. Compared to conventional chemical fertilizers, insect-pest and disease damage was reduced by 75.15% in green peas, 74.33% in cowpeas, 77.84% in cluster beans, 72.93% in cabbage, and 69.22% in cucurbits. These findings highlight the crucial role of neem-based compost and beneficial soil microbes in promoting systemic resistance, reducing reliance on agrochemicals, and fostering both food safety and environmental sustainability.