Controlling nematodes biologically

Root-knot nematodes (Meloidogyne spp.) are major pests of a range of crops in tropical and sub-tropical climates. The high cost of nematicides has precluded their use in subsistence agriculture, and management of root-knot nematodes has relied on the use of crop rotations, resistant or tolerant cultivars and a range of cultural and physical methods. Biological control agents (BCAs) are capable of providing effective control of some pests. The nematophagous fungus Verticillium chlamydosporium has shown considerable potential for reducing root-knot populations. Trials conducted in Zimbabwe have shown that the fungus was effective in reducing the number of healthy nematode eggs being produced, and that mechanical incorporation of the fungus into the soil was more effective than using soil drenches. The fungus survived in microplots for three years from a single application, which may be adequate to establish the fungus in the soil for several crop cycles. Some non-host and nematicidal crops currently used in management strategies to reduce root-knot nematode populations were found to support colonization by the fungus. This would suggest that the degree of nematode control could be enhanced and the length of rotation decreased by applying the fungus with these crops. The fungus could have considerable potential in management strategies for resource-poor farmers. Professor Brian Kerry IACR-Rothamsted Harpenden Hertfordshire AL5 2JQ, UKRoot-knot nematodes (Meloidogyne spp.) are major pests of a range of crops in tropical and sub-tropical climates. The high cost of nematicides has precluded their use in subsistence agriculture, and management of root-knot nematodes has relied on..