Short communication Biological control of plant-parasitic nematodes in pigeonpea ®eld crops using neem-based products and manurial treatments

The paper presents an account of a ®eld plot experiment to investigate the in ̄uence of soil applications of neem-based (Achook and Suneem G) and crop fertilizer (urea and cattle manure) treatments, separately and in combination on free-living, and plant-pathogenic nematode populations and crop productivity. All the treatments signi®cantly decreased the number of plant-parasitic nematodes with increasing doses. Combinations of both neem-products with urea were most effective in reducing plant-parasitic nematode populations. The neem products and product combinations with urea signi®cantly decreased numbers of free-living nematodes compared to controls; however, numbers increased in the cattle-manure-treated plots. The growth of pigeonpea (Cajanus cajan L.) was improved in all the treatments, in part due to the control of plantparasitic nematodes and in part due to manurial effects. Urea was phytotoxic at 330 kg N/ha applied alone; however, it was not phytotoxic at this rate in combination with the neem-based products. # 1999 Elsevier Science B.V. All rights reserved.