1. Field Evaluation of Certain Pesticides Against the Cotton Bollworms with Special Reference to their Negative Impact on Beneficial Arthropods (2006 cotton season, Minia region, Egypt) Abdelrahman M. Younis, S.H. Hamouda, S.A. Ibrahim, and Z.A. Zeitoun Plant Protection Department Faculty of Agriculture Minia University Minia, Egypt

2. Introduction ● In Egypt, about half a million feddans are cultivated with cotton, representing 6% of all cultivated lands. ● Earias insulana and Pectinophora gossypiella are serious pests infecting cotton in Egypt. ● Economical yields are impossible to achieve without their chemical control. ● Chemical control of cotton pests costs 12.5 million U.S. dollars.

3. The pink bollworm Pectinophora gossypiella larva adult damaged cotton bolls

4. The spiny bollworm Earias insulana damaged cotton boll larva adult

5. Objectives ● To select the most effective pesticides against cotton bollworms. ● To study the indirect effect on seed cotton yield. ● To study the side effects on natural enemies.

6. Materials & Methods ● Seven pesticides were evaluated. ● Earias insulana and Pectinophora gossypiella. ● Gossypium barbadens, (Giza 80 Cotton, variety). ● Cotton field was divided into 32 plots of 175 m 2 each. ● 100 green bolls/plot were collected for recording the infestation and larval content before and after spray.

7. ● Number of predators in each plot was monitored using a sweep net technique (Southwood, 1978). ● Reduction percentages were calculated (Henderson and Tilton, 1955). ● Seed cotton yield for each plot was weighed. ● Data was analyzed using analysis of variance (Gomez and Gomez, 1984).

15. Conclusion ● Synthetic pyrethroids exhibited the greatest efficiency in controlling bollworms. ● The Bt-bioproduct was significantly the least effective treatment in reducing bollworm infestations. ● Seed cotton yield was greater in pyrethroid treatments > OP's ≥ Bt-bioproduct > control.

16. ● The Bt-bioproduct resulted in the minimum negative impact toward beneficial arthropods. ● We suggest using gamma-cyhalothrin in rotation with the Bt-bioproduct to minimize the side effects on beneficials

17. Acknowledgements ● Financial support for this project was provided in part by the Ministry of Agriculture, Egypt. ● Financial support to participate and present this manuscript was provided in part by Minia University, Minia, Egypt.