Strategies for biological system management of nematodes in horticultural crops: fumigate, confuse or ignore them.

Abstract

Integrated management of nematodes as well as other soil-borne pests and diseases in horticultural crops in the tropics and subtropics as well as in protected cultivation in temperate climates is often a lopsided approach based on soil fumigation. With the upcoming loss of methyl bromide (Mbr), because of its effects on the ozone layer of the atmosphere, growers will have to make changes in the way they look at the problem of controlling soil-borne nematodes, fungi, insects and weeds. They can no longer rely on eradication of all pest problems with a one-stroke fumigation process. This is a severe problem that requires sound scientific solutions. New control technologies need to be developed and established methods urgently refined that are acceptable to the growers. Alternative fumigants and systemic nematicides still on the market will not provide broad spectrum control equal to Mbr. More disturbing is a provocative statement made by an economist that due to pesticides nematologists have neglected developing suitable alternative IPM measures of control. Some people may agree with this statement, especially if they are not involved in soil-ecosystem research. If you are a nematologist, this thought-provoking statement is at first upsetting but it is not valid. My talk will concentrate on the biological and cultural control methodologies that have been developed by nematologist around the world for use in management systems. These are technologies that can compensate for the loss of methyl bromide to horticultural crops in many countries. Alternatives are available and new methodologies are being developed for restructuring IPM strategies in many crops. The compatibility of these new approaches with general farming practices needs to be assessed on a country by country basis. Mutually interacting technology packages are needed, that are logically structured in "biological system management" programs that stress biocontrol aspects of control and not pesticides as is often the case in standard IPM approaches.