Evaluation of Release Patterns of The Parasitoids Eretmocerus Mondus and Encarsia Formosa (Hymenoptera: Aphelinidae) to Control The Whitefly (Homoptera: Alyerodidae) on Sweet Potato Plants

Document Type : Original Article

Author

Plant Protection Research Institute, Agricultural Research Center, Sabahia, Alexandria

Abstract

Three patterns of release for the parasitoid Eretmocerus mondus were compared with a low rate of Encarsia Formosa on the whitefly in sweet-potato fields. The patterns of Ere. mondus included that fixed weekly  release number (3females/plant/week), variable release (5 females/plant/wks 7) follow (1 females/plant/wks 7), low release rate (1 females/plant/wk), while a low release of Encarsia Formosa at (1 females/plant/wk) was compared. The control was without parasitoid releases and whitefly nymphal densities reached 33100 individuals /50 leaves after 10 weeks. In patterns of parasitoid release, percentage parasitism was 77.9% by fixed-rate Ere. mondus after 8 weeks, while it was 47.5% with variable rate Ere. mondus after 6 weeks. The low-rate of Ere. mondus and E. Formosa induced 64.5%, 62.0%, respectively after 14 weeks.
Releases of low numbers of E. formosa provided commercially acceplable whitefly control.
There was no difference between the fixed and variable release rate treatment of Ere. mondus, indicating a  high percentage of parasitism as a result of absence the host whitefly and honeydew increasing on the leaves. Also, the results proved that the low release gave satisfactory reduction on whitefly population and suitable parasitism percent to occur parasitoids continuously.

Files

Share

How to cite

Statistics