الفهرس 
CONTENTSOnly 14 pages are availabe for public view
 |  | from | 180 |  |  |
| | | from | 180 | | |
Abstract
Objective:For the purpose of minimizing the use of synthetic organic insecticides; the present study was conducted to evaluate the effect of two commercial bioinsecticides (Protecto® (Bacillus thuringiensis kurstaki) and Viruset® (Spodoptera littoralis NPV), and two commercial chitin synthesis inhibitors (Atabron® and Cascade®). Methods & Results: The present study was conducted to evaluate the effect of two commercial bioinsecticides Protecto® (B. thuringiensis) and Viruset® (S. littoralis NPV), and two commercial chitin synthesis inhibitors (Atabron® and Cascade®).1- Bioassay tests:Bioassay tests showed that Atabron was the most toxic compound in all tested compounds, evidenced by the very low LC50, values. The tested bioagents did not result in high mortalities 48 hours post treatment, however, mortality rates increased at the end of the larval stage.2- Biological studies:All tested compounds affected some biological aspects of treated 4th instar larvae of S. littoralis. The treatment resulted in an increase in larval duration in the tested bio agents and was shortened in the case of treatment with IGR’s. All tested compounds have reduced the mean pupal duration. In addition, there was a significant decrease in adult emergence and mean adult longevity. Reduction in the reproductive potential of S. littoralis moths derived from 4th instar larvae was observed.3- Histopathological and ultrastructure studies: Many histopathological changes in the midgut of the 6th instar larva were obtained due to treatment with Protecto®, Viruset®, Atabron® and Cascade®. All treatment has effective against the midgut epithelial cells. All treatment has caused increased cytoplasm vacuolization. The viral infection has affected the nucleus and the chromatin material, since the nucleus is the target site of the viral replication. Secretory and lipid vesicles were observed as a result of bacterial infection. The cell organelles have been malformed and lost their integrity due to all treatment infection, while all treatment infection has caused many cell organelles to disappear and induced the marker of the cell death.4- Biochemical studies:This experiment was conducted on the 4th instars larvae of S. littoralis to investigate the effect of Protecto®, Viruset®, Atabron® and Cascade®. The effect of the tested compounds on the total protein, total carbohydrate, and total lipids were determined in the 6th instars larvae. After treatment the 4th instars larvae results showed that the treatment of the 4th instar larvae with the LC50 of the tested compounds represented a significant decrease in the amount of total protein, total carbohydrate, and total lipid.