Entomology

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Author: search.filters.author.Dively, Galen P.

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    Comparative Efficacy of Common Active Ingredients in Organic Insecticides Against Difficult to Control Insect Pests
    (MDPI, 2020-09-08) Dively, Galen P.; Patton, Terrence; Barranco, Lindsay; Kulhanek, Kelly
    There exists a lack of control efficacy information to enable decision-making about which organic insecticide product works best for a given insect pest. Here, we summarize results of 153 field trials on the control efficacy of common active ingredients in organic insecticides against 12 groups of the most difficult to control insect pests. These trials evaluated primarily the organic products Entrust (spinosad), Azera (pyrethrin and azadirachtin), PyGanic (pyrethrin) and Neemix (azadirachtin), which reduced pest infestations by an overall 73.9%, 61.7%, 48.6% and 46.1% respectively, averaged across all trials. Entrust was the most effective control option for many insect pests, particularly providing >75% control of flea beetles, Colorado potato beetle, cabbageworms and alfalfa weevil, but was relatively ineffective against true bugs and aphids. Azera provided >75% control of green peach aphid, flea beetles, Japanese beetle, Mexican bean beetle, potato leafhopper and cabbageworms. PyGanic was less effective than Entrust and Azera but still provided >75% control of green peach aphid, flea beetles and potato leafhopper. The growth inhibition effects of azadirachtin in Neemix were particularly effective against larvae of Mexican bean beetle and Colorado potato beetle but was generally less effective in trials with insect infestations consisting mainly of adult stages. Those insect pests that were particularly difficult to control included thrips, stinkbugs, cucumber beetles and fruitworms. Several caveats pertaining to the application of the results are discussed.
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    An Evaluation of Cultural and Chemical Control Practices to Reduce Slug Damage in No-till Corn
    (MDPI, 2022-03-11) Dively, Galen P.; Patton, Terrence
    Slugs, primarily the gray garden slug, Deroceras reticulatum (Müller), are the most damaging non-arthropod pest of corn grown in conservation tillage systems in the US. These mollusks favor decaying plant residue on the soil surface, which provides food, shelter and optimum microenvironmental conditions for their development and survival. Here, field plot experiments evaluated several cultural and chemical control practices to suppress slug activity and feeding injury during early seedling growth. The use of row cleaners to remove surface residue over the seed row and starter fertilizer applied different ways during planting significantly reduced the percentage and severity of plants damaged by slugs by negatively affecting their activity around emerging seedlings and providing more favorable conditions for plants to outgrow and tolerate feeding injury. As rescue treatments, reduced rates of a 4% molluscicide bait applied as a directed band over the seed row, and broadcasted solutions of urea-based nitrogen applied under calm winds at night provided effective slug control. Practical considerations of these treatments are discussed, as well as changes in weather patterns and current planting practices that have had contrasting effects on slug populations and their potential damage.
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    Assessment of Chronic Sublethal Effects of Imidacloprid on Honey Bee Colony Health
    (PLoS (Public Library of Science), 2015-03-18) Dively, Galen P.; Embrey, Michael S.; Kamel, Alaa; Hawthorne, David J.; Pettis, Jeffery S.
    Here we present results of a three-year study to determine the fate of imidacloprid residues in hive matrices and to assess chronic sublethal effects on whole honey bee colonies fed supplemental pollen diet containing imidacloprid at 5, 20 and 100 μg/kg over multiple brood cycles. Various endpoints of colony performance and foraging behavior were measured during and after exposure, including winter survival. Imidacloprid residues became diluted or non-detectable within colonies due to the processing of beebread and honey and the rapid metabolism of the chemical. Imidacloprid exposure doses up to 100 μg/kg had no significant effects on foraging activity or other colony performance indicators during and shortly after exposure. Diseases and pest species did not affect colony health but infestations of Varroa mites were significantly higher in exposed colonies. Honey stores indicated that exposed colonies may have avoided the contaminated food. Imidacloprid dose effects was delayed later in the summer, when colonies exposed to 20 and 100 μg/kg experienced higher rates of queen failure and broodless periods, which led to weaker colonies going into the winter. Pooled over two years, winter survival of colonies averaged 85.7, 72.4, 61.2 and 59.2% in the control, 5, 20 and 100 μg/kg treatment groups, respectively. Analysis of colony survival data showed a significant dose effect, and all contrast tests comparing survival between control and treatment groups were significant, except for colonies exposed to 5 μg/kg. Given the weight of evidence, chronic exposure to imidacloprid at the higher range of field doses (20 to 100 μg/kg) in pollen of certain treated crops could cause negative impacts on honey bee colony health and reduced overwintering success, but the most likely encountered high range of field doses relevant for seed-treated crops (5 μg/kg) had negligible effects on colony health and are unlikely a sole cause of colony declines.
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    Adjacent Habitat Influence on Stink Bug (Hemiptera: Pentatomidae) Densities and the Associated Damage at Field Corn and Soybean Edges
    (PLOS (Public Library of Science), 2014-10-08) Venugopal, P. Dilip; Coffey, Peter L.; Dively, Galen P.; Lamp, William O.
    The local dispersal of polyphagous, mobile insects within agricultural systems impacts pest management. In the mid- Atlantic region of the United States, stink bugs, especially the invasive Halyomorpha halys (Stal 1855), contribute to economic losses across a range of cropping systems. Here, we characterized the density of stink bugs along the field edges of field corn and soybean at different study sites. Specifically, we examined the influence of adjacent managed and natural habitats on the density of stink bugs in corn and soybean fields at different distances along transects from the field edge. We also quantified damage to corn grain, and to soybean pods and seeds, and measured yield in relation to the observed stink bug densities at different distances from field edge. Highest density of stink bugs was limited to the edge of both corn and soybean fields. Fields adjacent to wooded, crop and building habitats harbored higher densities of stink bugs than those adjacent to open habitats. Damage to corn kernels and to soybean pods and seeds increased with stink bug density in plots and was highest at the field edges. Stink bug density was also negatively associated with yield per plant in soybean. The spatial pattern of stink bugs in both corn and soybeans, with significant edge effects, suggests the use of pest management strategies for crop placement in the landscape, as well as spatially targeted pest suppression within fields.