Effect of Low-lying Land Environment on Abundance of Cotton Spider Mites and Total Phenolic Content of Leaves and their Relationship

The possible advantage of cotton production established in low-lying land area over intensive culture pond was investigated by comparing the abundance of cotton spider mites on these plants to that in conventional production areas at the Jiangbei farm, Hubei Province, China. Cotton fields recently grown at low-lying land area supported significantly lower populations of cotton spider mites than conventional long established cotton fields. There were no significant differences in mite populations between cotton fields established in low-lying land area in the current year or 1 or 2 years earlier. The pest control advantage provided by pond areas was present whether or not acaricides were used. The total phenolic content of cotton leaves differed occasionally between treatments but did not seem to have affected the abundance of mites. The number of eggs, larva-nymph-adults, egg-larva-nymph-adults, the percentage of host plants colonized by cotton spider mites and the plant damage index were independent of the total phenolic content in leaves. The results are discussed in relation to integrated pest management and the mineral balance hypothesis.