Efficacy of Vacuum Machines for Lygus hesperus (Hemiptera: Miridae) Control in Coastal California Strawberries

Abstract

Three representative suction machines were evaluated for control of Lygus hesperus (Knight) on strawberries for two growing seasons in production fields. Weekly and twice-weekly vacuum passes through a field were compared with bifenthrin applications in 1989. Weekly and twice-weekly vacuum passes were compared with bifenthrin (0.11 kg [AI]/ha) and malathion (1.26 kg [AI]/ha) sprays applied using a degree-day phenology model and with a combination of malathion and weekly vacuuming in 1990. All three machines reduced damage caused by L. hesperus when compared with the untreated control. The three-bed vacuum is the largest machine, with the highest air flow, tested, resulting in a significant reduction in damage compared with the untreated. The smaller one-bed and two-bed machines did not decrease the numbers of nymphs or damage. However, the treatments in which vacuum machines were used exclusively had damage that was not economically acceptable. Twice-weekly vacuum passes did not improve L. hesperus control compared with weekly vacuum passes. Weekly vacuum passes combined with malathion sprays were no better than either treatment alone. Bifenthrin provided effective control but resulted in spider mite (244.6 mites per leaflet) population increases after 3-4 wk. Weekly vacuum treatments provided control of L. hesperus equal to that of one or two applications of malathion.