Effectiveness of commercial formulations of Bacillus thuringiensis var Kurstaki "Agerin, Dipel 2X and Dipel DF" on total protein and lipid contents were studied. Activities of detoxification and metabolic enzymes were also measured in treated and control larvae of cotton leafworm Spodoptera littoralis. Collected samples from treated larvae at intervals of 48 and 120 hrs post treatment were analyzed to assess the total protein and lipid contents as well as the enzymes activities. Significant reductions were observed in total protein content at 120 hrs larvae in all treatments compared with control. In all larvae treated with Agerin and Dipel DF the lipid content was significantly elevated after 48 and 120 hrs of treatment while Dipel 2X showed no significant difference in lipid content. However, fluctuated changes in the enzymes activity of treated larvae were found. We conclude that there are differences in biochemical effects between various commercial formulations of Bacillus thuringiensis kurstaki. In most cases Agerin was found more effective on S. littoralis than others.

Larvicidal efficacy of a new semi-synthetic avermectin derivative Methylamine avermectin (Radical 0.5% EC) was determined against larval instars of the Egyptian cotton leafworm, Spodoptera littoralis (Biosd.) in the laboratory, field and semi field experiments. 2 nd and 4 th instar larvae showed greatest susceptibility to the Radical in the laboratory experiment. The LC 50s values of the 2 nd and 4 th larval instar after 48 hours were 0.005 and 0.008 ppm, respectively. Radical was tested with recommended dosage (200 ml / 100 liter water) in field; it caused 84.6% reduction of pest population up to day 8 post-treatment. On the other hand, the semi field application of the same recommended dose on the 2 nd instar larvae showed general mean 73.6% mortality, 7 days after post-treatment. Also, some biochemical changed in the 4 th instar larvae after 48 hours of treatment with tested bioinsecticide were measured. It's clear from the results that activities of trehalase, invertase and acetylcholine esterase were increased in all treatments. Tested bioinsecticide reduced the activity of alkaline phosphatase at all doses compared to untreated larvae. No significant changes in acid-phosphatase activities were observed at all treatment doses. On studying the effect of esterases isozymes patterns, there were no differences in number and position of esterases isozymes between untreated and treated larvae in the whole larval body tissues although each band different in its concentration. The toxicity of the formulation to some beneficial predators was also evaluated in the field. There was no detectable effect of these bioinsecticide on naturally occurring beneficial species.

Effect of gamma radiation on the whole body contents of nutritional materials was investigated for potato tuber moth, Phthorimaea operculella Zeller, fed on irradiated potato tubers. The statistical analysis of the data indicated that the quantities of carbohydrates, proteins and lipids in the whole body of the adults of Ph. operculella were affected significantly. There was a correlation with their changes in the potato tubers; as a significant decrease in protein and carbohydrate contents was recorded for potato tubers and both male and female moths at most doses. Although lipid was recorded as a trace amount in both non-irradiated and irradiated potatoes it was significantly increased in males fed on irradiated potatoes at all doses. While a significant decrease in lipid contents at lower doses (50 and 70 Gy) was recoded , a significant increase at higher doses (100, 150 and 200 Gy) was noticed in case of females. The total body weight of insects was affected directly with the increase in the dose of potato irradiation

The present study investigated the effect of dietary changes on differential and total haemocyte counts (THCs) and midgut histopathologiocal changes of S. gregaria injected with Bacillus thuringiensis israelensis (Bti). THCs of Bti-injected adults significantly decreased in all insects fed on all experimental plants. In Bti-injected locusts, prohaemocytes (PRs) percent decreased in insects fed on grass and quietly disappeared in other treatments. plasmatocytes (PLs) percent increased, while the granulocytes (GRs) decreased in all tested insects fed on sorghum, sesban, grass and clover than those of the control. The percentages of oenocytoids (OEs) increased in all treatments except in insect fed on sesaban. The results indicated that insects fed on clover had the highest number of haemocytes, while those fed on grass had the lowest number. Certain pathological symptoms in the midgut of Bti treated adults were observed after 48 hr post injection, such as (1) disorganisation, disintegration and vacuolization of epithelial cells, (2) lysis of the basement membrane and surrounding muscles and (3) detachment of microvilli from epithelial cells. The most deformed group to Bti was grass fed locust. Subsequently, the host plant could be a major factor that affect on the response of herbivorous insects to pathogens.

Potato tubers were irradiated with different doses of gamma irradiation (50,100 and 200Gy), and fed by the larvae of Phthorimaea operculella (Lepidoptera : Gelechiidae), to measure the effect of larval feeding on some biochemical components of the adult stage. The data indicated that the change in larval diet (tubers) due to irradiation led to some changes in such biochemical components of the adult. Irradiation increased phenolic content and oxidation capacity of potato tubers, while vitamin C was significantly reduced. Vitamin C content of the adult was not significantly changed at most doses. From the nutritional point of view, this means that the decrease in a nutrient in the diet not necessitate corresponding suppression in the feed insects. Acid and alkaline phosomonoesterases activities and trehalose content of the adult were significantly depressed. Such depression was related to the increased phenolic content of potato tubers after irradiation. This provides an evidence that irradiation of potato tubers could leads to products which might be toxic to insects and able to change in the diet (tubers) component that fed by the larvae. It is interesting to realize that ionizing irradiation inactivate pathogens or directly killed store insect stages, but also could control reinfestation of pest by producing changes in nutrients of potato tubers, and increasing toxic compounds, resulting in abnormalities which could extent to the adult stage and reduce its reproductive capacity.