Cotton aphid, Aphis gossypii Glover (Homoptera: Aphididae) is considered a key pest of cotton in Egypt. Hence, field and laboratory studies were conducted at Sakha Agriculture Research Station, Egypt during seasons 2016 and 2017. Efficiency of seven insecticides i.e., flonicamid, imidacloprid, thiamethoxam, emamectin-benzoate, chlorpyrifos, methomyl and deltamethrin against A. gossypii in cotton fields were evaluated. Their side effects on the associated predators, soil fauna and plant defense enzymes also were studied. Flonicamid was the most effective against A. gossypii. The efficacy of imidacloprid and thiamethoxam did not differ significantly from that of chlorpyrifos and methomyl recording from 83.28-93.27% reduction in A. gossypii infestation. Flonicamid, emamectin-benzoate, imidacloprid and thiamethoxam were the least harmful to the associated predators causing less than 50% mortality, while the others were highly toxic. Flonicamid exhibited the highest degree of safety to the soil micro-arthropods, followed by emamectin-benzoate, methomyl and deltamethrin. In contrast, chlorpyrifos and imidacloprid were the most toxic to the soil microarthropods. The conventional insecticides (chlorpyrifos, methomyl and deltamethrin) increased the activity of catalase and peroxidase causing physiological stress on the treated cotton plants, whereas the other tested insecticides recorded decreases in catalase and peroxidase activities inducing the plant defense response. Only imidacloprid and thiamethoxam increased the activity of polyphenol oxidase. Emamectin-benzoate and deltamethrin decreased the total soluble protein content, while the others tested insecticides caused increases in this criterion comparing to the control.

The soft scale insect kilifia acuminata (Signoret) (Hemiptera: Coccidae) is one of the main insect pests infesting mango trees and caused the damage for leaves and fruits. The population density of the soft scale insect k. acuminata during the first year of study 2014/15 recorded 6 peaks and the highest peak was 1539 indiv.on 27 th of March, 2015. While recorded 5 peaks during the second year 2015/16 and the highest peak was on 17 th of June 2016 and represented by 1178 indiv. The highest average number and percentage in the first year was recorded during autumn season and represented by 1023.1 indiv. /100 leave (30.2%), while the highest average number and percentage was recorded during spring and represented by 994.8indiv./100 leaves (29%) in the second year. The highest average number of the soft scale insect K. acuminata were recorded in the south direction during the two successive years 2014/15 and 2015/16 and represented by 225.9+19.6 and 241.4+18.3 indiv. /100 leaves, respectively. On the other hand, the lowest average number were recorded in the North direction and represented by 105.4+16.1 and 74.8+6.2 indiv. /100 leaves, respectively. Statistical analysis showed that, a highly significant differences between the different directions, during the two successive year of study.