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Northeastern U.S. farms are often situated adjacent to forestland due to the heterogeneous nature of the landscape. We investigated how forested areas influence Carabidae diversity within nearby crop fields by establishing transects of pitfall traps. Trapping extended across a forest-agriculture ecotone consisting of maize, an intermediate mowed grass margin, and a forest edge. Carabidae diversity was compared among the three habitats, and community and population dynamics were assessed along the transect. We used a principal response curve to examine and visualize community change across a spatial gradient. The highest levels of richness and evenness were observed in the forest community, and carabid assemblages shifted significantly across the ecotone, especially at the forest-grass interface. Despite strong ecotone effects, population distributions showed that some species were found in all three habitats and seemed to thrive at the ecotone. Based on similarity indices, carabid assemblages collected in maize adjacent to forest differed from carabid assemblages in maize not adjacent to forest. We conclude that forest carabid assemblages exhibit high degrees of dissimilarity with those found in agricultural fields and forested areas should thus be retained in agricultural landscapes to increase biodiversity at the landscape scale. However, ecotone species found at forest edges can still noticeably influence carabid community composition within neighboring agricultural fields. Further studies should determine how these shifts in carabid assemblages influence agroecosystem services in relation to ecosystem services observed in fields embedded in an agricultural matrix. [ABSTRACT FROM AUTHOR]

The effect of prohexadione-calcium, a plant growth regulator that inhibits gibberellin metabolism, on Cacopsylla pyricoloa (Foerster) in pear trees, and Choristoneura rosaceana (Harris) and Aphis spireacola Patch, in apple trees was studied. C. pyricoloa and A. spireacola populations were significantly reduced in prohexadione-calcium-treated pear and apple, respectively. Insecticide control of both pests with imidacloprid was synergized in treatments with prohexadione-calcium. In apples treated with prohexadione-calcium, there was a significant reduction in the number of C. rosaceana shelters per tree and amount of fruit injury at harvest attributable to the C. rosaceana. There was an additive effect when tebufenozide was used to control C. rosaceana in trees treated with prohexadione-calcium. Prohexadione-calcium significantly reduced vegetative growth in both pears and apples. Synergistic and additive treatment effects of prohexadione-calcium and pesticides used in this study may be due to better penetration and coverage of pesticides due to reduced foliar growth or to changes in the nutritional quality of the host plants. [ABSTRACT FROM AUTHOR]

The sublethal effects on development and reproduction of previously estimated LC10 and LC25 of azinphosmethyl, several classes of insect growth regulators (IGRs), and abamectin were evaluated on a laboratory susceptible strain of the tufted apple bud moth, Platynota idaeusalis (Walker). Neonates (5th instars in the case of fenoxycarb) were exposed through ingestion of diet treated on the surface. The following parameters were evaluated; larval and pupal duration, mortality of each stage and sex, pupal weights, and fecundityand fertility. At the concentrations evaluated, azinphosmethyl and diflubenzuron did not affect development or reproduction of either sex, but diflubenzuron caused higher pupal mortality in males compared with females. Tebufenozide reduced fecundity in matings in which the larvae of both sexes had been treated, whereas abamectin increased thedevelopmental time from neonate to adult eclosion and greatly affected fecundity. Exposure of 5th instars to fenoxycarb greatly increasedduration of the larval stage and pupal weight in female larvae, but not in male larvae. Fecundity and fertility also were affected. [ABSTRACT FROM AUTHOR]