INTERACTION OF NEMATODES AND VERTICILLIUM WILT ON COTTON IN UZBEKISTAN: REGULATION OF DENSITY OF NEMATODE POPULATION IN COTTON AGROCENOSIS
Institute of Genetics and Plant Experimental Biology, AS, Tashkent PO Box 97, Uzbekistan
Background and objectives
Results and conclusions
Various agricultural methods to influence the density of nematode populations in soil have been defined. Of 22 agrotechnical actions studied, nine decreased nematode numbers (from 25 to 67%), eight did not have any marked influence (within 15%); and five increased the density of nematode populations (from 40 to 177%). Thus various anti-wilt measures change the field nematode complex. If protective anti-wilt crop rotations are carried out, taking into account their influence on nematode populations, their anti-wilt effect can be enhanced. So the anti-wilt steps reducing nematode numbers in soil must follow those which promote nematode numbers to support and prolong their useful protective action. It is best to use every practice separately in a system of defensive steps. In the case of combining two anti-wilt agricultural methods or rotational crops, it is necessary for one of them to promote reduction of nematode density in the rhizosphere of plants. Two or more agrotechnical actions should not be used one after another to enhance the anti-wilt effect if both promote a rise in nematode numbers. It may cause a sufficient accumulation of nematodes and then the total anti-wilt action will be less prolonged and more weakened.