The work aimed to indicate the differences in species and population densities of pests, which were found on the eggplant plantations (cv. Roma) in summer and autumn seasons in Alexandria.
The results showed that presence of the red spider mite (Tetranychus urticae), whitefly (Bemisia tabaci), potato tuber moth (Phthorimae opercellula), semi-looper (Autographa spp.), onion thrips (Thrips tabaci) and the predator aphid-lion (Chrysopa vulgaris) in autumn season. While, T.urticae, B. tabaci and Autographa spp. were found in summer.
T.urticae gave the highest number in the two seasons, especially in autumn. The general averages () of eggs, nymphs and adults were 85, 57.1 and 38.8 individuals/plant, respectively. The corresponding figures were 47.2, 43.1 and 15.1 in summer.
Few numbers of the other-mentioned pests were counted in comparison with T. urticae in the two seasons. Therefore, T. urticae constitutes the major pest on eggplant and increases in autumn due to high temperature and PSD (possible sunshine duration).
Therefore, effects of some climatic conditions in the two seasons on presence and numbers of pests were studied. In autumn, the simple correlation analysis indicated that PSD was the most effective on eggs of T. urticae. Also, amount of rain showed significantly negative correlations on T. urticae stages in autumn season. Concerning summer season, PSD had significantly effect on adults of T. urticae. It is evident that some climatic conditions have effects on population dynamics of some pests, and PSD was the most important factor on T. urticae.
Also, treatments of abamectin and micronized sulfur induced reduction in eggs, nymphs and adults of T. urticae after 2, 5 and 7 days of application with the highest effect of abamectin after 7 days. Significant differences were noticed between treatments and days post-treatment.