SAMPLING FOR LYGUS-HESPERUS (HEMIPTERA, MIRIDAE) IN STRAWBERRIES

Several suction sampling devices were compared with a beating tray and a whole-plant sample for determining population abundance of Lygus he sperus (Knight) as well as some beneficial predatory arthropods (Geoco ris spp., Hemerobius spp., Chrysopa carnea (Stephens), Orius tristicol or (White), and spiders) in California strawberry fields. The Allen-va c (A-vac) sampler best approximated the whole-plant sample for L. hesp erus and beneficials except spiders. The beating tray provided the mos t consistent though lower estimates, but could provide a useful estima te of L. hesperus and beneficial arthropod abundance in an integrated pest management monitoring program. The D-vac provided a slightly lowe r estimate of L. hesperus density than did the A-vac samples or beatin g-tray samples at a greater cost in sampling time. For each regression of relative technique against the corresponding whole-plant estimate, the intercept was not significantly different from 0. Taylor's power law was used to develop variance-mean models for each sampling type te sted.