EVALUATION OF VERMICOMPOST AND EXTRACTS ON TOMATO ROOT-KNOT NEMATODE

A laboratory assay and pot experiment were conducted to explore the influence of different concentrations of vermicompost and its extracts against root-knot nematode in tomato. The results showed that the hatchability of eggs significantly decreased with increasing concentrations of vermicompost extract. The knockdown rate and mortality of Meloidogyne incognita J2s significantly increased with increasing concentrations of vermicompost extract and treatment time, and the mortality rates reached up to 88.46% at a concentration of 90% compared to that of the untreated control. Pot experiments showed that the number of root-knots reduced and the relative control effect was improved. Introduction Many types of organic wastes, such as straw residue, fungus chaff, sesame residue, biogas slurry, livestock manure, green manure, rice bran, and grain processing by-products, have effects of improving soil environments, alleviating continuous cropping barriers, preventing and controlling soil-borne diseases and promoting plant growth. Because this type of material is cheap, simple and easy to obtain and has a wide range of sources, more and more research has been conducted on this type of material as the matrix of new crop cultivation and disease prevention. Vermicompost is the main product of the biodegradation of organic waste by earthworms, and contains some antagonistic microorganisms. It has a good control of the occurrence of soil-borne pathogens of crops (Hu et al. 2004, Wang et al. 2010). As a biological organic fertilizer, vermicompost plays an important role in the field of applied research to control soil-borne diseases, and the use of vermicompost added to fertilizer or cultivation matrix for the control of soil-borne diseases has been reported. Suppression of Plasmodiophora brassicae, Phytophthora nicotianae and Fusarium lycopersici by vermicomposts has been reported (Nakamura 1996, Szczech 1999). It was demonstrated that fungal diseases of gerbera plants, such as Rhizoctonia solani, Phytophthora drechsleri and Fusarium oxysporum, were generally suppressed by the incorporation of vermicompost into the growth media (Rodriguez et al. 2000). Sporulation reduction of the pathogen Phytophthora cryptogea after treatment with vermicomposts was described (Orlikowski 1999). Previous studies showed that aqueous extracts of vermicomposts inhibited the mycelial growth of Botrytis cinerea, Sclerotinia sclerotiorum, Corticium rolfsii, Rhizoctonia solani and Fusarium oxysporum (Nakasone et al. 1999). Adding a proper amount of vermicompost to the cultivation matrix had some preventive effects on few common soil-borne diseases such as damping-off and wilt (Edwards et al. 2004). It was reported that addition of organic additives such as green manure, barnyard manure and compost was effective for improving soil conditions, such as by the release of nitrogen compounds, organic acids, or other compounds that had adverse effects *Author for correspondence: <liudawei353@163.com>. Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Northeast Region), Ministry of Agriculture/Northeast Agricultural University, Harbin, 150030, China. College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058, China.