APPLICATION OF NON-TRADITIONAL APPROACHES AND PESTICIDE RATIONALIZATION AGAINST CERTAIN COTTON PESTS

Abstract

Cotton is one of the most strategically and important crops in Egypt. This crop is attacked by many pests throughout the growing season which caused a considerable damage in both quantity and quality of cotton yield. The present investigation aimed mainly to study a group of most serious pests that invade cotton plants i.e., the cotton aphid Aphis gossypii Glover, the cotton whitefly, Bemisia tabaci (Genn.); the cotton .leafhopper Empoasca lybica de Berg; the Egyptian cotton leafworm, Spodoptera littora/is (Boisd.), the spiny bollworm, Earias insu/ana (Boisd.) and the pink bollworm Pectinophora gossypiel/a (Saunders). The following aspects are involved in this study where the

results could be summarized as follows:

1. Effect of nitrogen fertilization rates, plant density and distribution and their interaction on the cotton plant canopy, yield and yield components as micro­ environmentalfactors prevailing in cotton fields. 1.1. Cotton plants canopy:

1.1.1. Effect of nitrogen fertilization rates:

The result showed that when the nitrogen levels increased, the plant height and the number of leaves/plant were significantly increased. The rate of increase was higher at the addition of 100 kg. N /fed., as compared with other nitrogen rates 1.1.2.Effect of plant density and distribution:

By increasing the plant density from 45 to 75 thousand plants/ fed., higher plants were obtained, but the number of leaves and fruiting branches/plant was decreased significantly 1.1.3.Effect of the interaction between nitrogen rates and

plant density and distribution: