Effects of Various Levels of Nitrogen, Phosphorus, and Potassium in Nutrient Solution, on the Fecundity of the Two-Spotted Spider Mite, Tetranychus Bimaculatus Harvey (Acarina. Tetranychidae) Reared on Cucumber1

Studies were conducted on the effects of various levels of nitrogen, phosphorus, and potassium on the fecundity of the two-spotted spider mite, Tetranychus bimaculatus Harvey, on cucumber plants grown on a vermiculite base to which nutrient solutions were added The minor element concentrations were not varied Nutrients supplied were measured Statistically the experiment was set up as a 3 × 3 × 3 factorial confounded in blocks of 9 units, the second order interaction being partially confounded There were 4 replications, each having 27 treatment combinations No foliage analysis was carried out Populations of the mite were doubled when the concentration of the nitrogen was doubled Higher rates of nitrogen and potassium had a highly significant effect in increasing the fecundity of the mite. Significant population increases were also ascribed to interactions between increased nitrogen and potassium dosages and nitrogen and phosphorus dosages