EVALUATION OF SERANGIUM PARCESETOSUM (COLEOPTERA: COCCINELLIDAE) FOR BIOLOGICAL CONTROL OF SILVERLEAF WHITEFLY, BEMISIA ARGENTIFOLII (HOMOPTERA: ALEYRODIDAE), ON POINSETTIA

Abstract

Control of silverleaf whitefly (Bemisia argentifolii Bellows & Perring) on greenhouse poinsettia with biological agents has been unreliable. Serangium parcesetosum Sicard, a coccinellid predator, appears to have great potential for silverleaf whitefly control. In our study, dynamic changes in B. argentifolii populations on caged poinsettia in response to S. parcesetosum were monitored. Silverleaf whiteflies were introduced to caged poinsettias at 1 or 10 adults per plant and 6 weeks later S. parcesetosum were introduced at 0, 2 or 4 adults per plant. Within 2 weeks of Serangium release whitefly mortality increased dramatically, and for the ensuing 10 weeks whitefly levels remained at or near those observed at time of predator release. Beetle larvae were observed 2 to 10 weeks after Serangium release when prey was initially high but not when prey was initially low. Thus, whitefly control was primarily due to prolonged survival and continuous feeding of individual beetles. Our data suggest that Serangium may work well in a multiple species biological control program for whiteflies on poinsettia. However, further study is needed on multiple species interactions within the host (pest/plant) species, and on release management strategies.