Effect of Short-Term Releases of Chrysoperla rufilabris (Neuroptera: Chrysopidae) Against Silverleaf Whitefly (Homoptera: Aleyrodidae) in Field Cages2
We studied the effect of different lacewing (Chrysoperla rufilabris [Burmeisterl release rates on control of the silverleaf whitefly, Bemisia argentifolii Bellows and Perring, inside field cages in organically-grown watermelon and in Lablab purpureus, a leguminous forage crop. Second-instar C. rufilabris larvae were released at rates of 0 (control), 10, 25, and 50 per cage (0.37 m2 area). Whitefly counts were made prior to release and compared with those taken 48 h after release of the lacewings. In the watermelon field, the control had approximately 35% more whiteflies over the entire season as compared to the predator treatment with the highest whitefly counts (25 lacewings per plant). The effects of predator releases were most evident during the second half of the season. However, higher rates of predator release did not result in increased pest suppression. No significant patterns of prey suppression were detected in the legume field, possibly because prey densities were already too high at the start of the experiment. Whitefly population dynamics in the lablab was apparently determined by environmental factors and crop phenology, rather than by predation. Possible reasons are presented for observed differences in degrees of pest suppression afforded by lacewing larvae in order to optimize control of the whitefly populations.
Contributor Notes
2 Mention of a company or proprietary product does not constitute an endorsement by the Agricultural Research Service or the U.S. Department of Agriculture.
3 Current address: Texas Ag. Expt. Sta., 2415 East Hwy. 83, Weslaco, TX 78596.
4 Current address: USDA, ARS, National Program Staff, BARC-WEST, Bldg. 005, Beltsville, MD 20705.
5 Joint affiliation: Biological Control of Pests Research Unit, USDA-ARS-SARL, and Texas Ag. Expt. Sta., 2413 E. Hwy 83, Weslaco, Texas 78596.