Browsing by Subject "Integrated pest management"

Now showing 1 - 3 of 3
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    Compatibility of soybean aphid integrated pest management strategies
    (2012-12) Heidel-Baker, Thelma Tolentino
    The soybean aphid, Aphis glycines, is a major economic pest of Midwest soybean. Since its discovery in the United States in 2000, significant strides have been made in developing an integrated pest management (IPM) program for this pest. The primary method of controlling soybean aphid outbreaks is through the use of foliar insecticides, but alternative management strategies such as host plant resistance varieties, reduced-risk insecticides and neonicotinoid seed treatments are also available. In addition, natural control from soybean aphid natural enemies can contribute towards aphid suppression. Conserving these natural enemies is an important component of soybean aphid IPM. The focus of this dissertation is to better understand the interactions between the management strategies currently available for soybean aphid management and whether the strategies are 1) effective at managing soybean aphid populations and 2) can successfully be utilized in combination with natural enemies to improve on soybean aphid IPM. To investigate these questions, both laboratory and field studies were conducted over three field seasons. Field studies demonstrated varying impacts of reduced-risk insecticides on the soybean aphid and its natural enemies. Minimal effects on soybean aphid and their natural enemies were demonstrated from the use of aphid resistant soybean and seedtreated soybean. Laboratory studies showed minimal non-target risks to natural enemies from exposure to seed treatments and host plant resistance. A field study to enhance aphid biological control with a buckwheat intercrop demonstrated minimal effects on either aphid or natural enemy populations. In summary, alternative soybean aphid management strategies exist that successfully suppress aphid population while also minimizing risks to natural enemies. Results of this research will help improve the integration of management strategies in soybean aphid IPM.
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    The effect of relative humidity on acaricide efficacy against and dispersal characteristics of the mold mite Tyrophagus putrescentiae
    (2013-06) Freitag, Jessica Anne
    This study determined the effects of relative humidity on mold mites (Tyrophagus putrescentiae) with regard to acaricide efficacy and dispersal characteristics. The mold mite is a stored product pest that can infest retail habitats. Mold mite survival depends on relative humidity (RH), and RH levels may affect efficacy of residual acaricides. In a simulated retail habitat, increasing humidity levels generally decreased acaricide efficacy. Results indicated that some acaricides may create a barrier against this mite. A second study analyzed mold mite dispersal characteristics. Mite infestations may remain undetected until mites leave the food package. Arenas provided an enclosed food reservoir incubated at high RH, and an open space incubated at one of three RH levels. Mite activity was monitored daily until dispersal characteristics were determined. Explosive dispersal, a mass-migration within 24 h, was observed. Therefore, direct sampling of habitat may be necessary to detect infestations before explosive dispersal has occurred.
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    Spotted-wing Drosophila: Investigating the Efficacy of Innovative and Alternative Management Techniques
    (2020-01) Gullickson, Matthew
    Spotted-wing drosophila (Drosophila suzukii; SWD) established recently in North America as an invasive insect pest of small and soft skinned fruit, responsible for significant economic losses nationwide and locally in Minnesota. Female SWD use a heavily sclerotized and serrated ovipositor to deposit eggs in ripening and ripe fruit. Larvae then emerge and develop within the flesh which results in unmarketable fruit at harvest. Consequently, there is a zero-tolerance threshold for larvae in fresh fruit. Current management strategies are often limited to regular applications of broad- spectrum insecticides, primarily organophosphates, spinosads, and pyrethroids. Weekly sprays may have deleterious ecological impacts to beneficial, non-target species including pollinators. Additionally, frequent spraying can contribute to insecticide resistance and may even fail to adequately protect fruit from infestation. Organic pesticide application for SWD management is particularly difficult for growers due to fewer chemical options and increased cost compared to conventional products. Since the arrival of SWD and the subsequent increase of insecticidal sprays, it has been a significant challenge for producers to balance economics as well as pest and pollinator management goals. Weekly conventional insecticide rotations in primocane raspberries can still result in widespread infestation likely due to high SWD populations, immigration by new individuals, and/or inadequate spray penetration in the dense plant canopy. Frequent applications of broad spectrum insecticides continues to be the most prevalent management strategy, but pesticide resistance is a concern. Resistance has already been reported for one of the only effective insecticides labeled for organic production systems, underscoring the need to diversify management strategies. Responding to the critical need for additional management tools and chemical alternatives, the goal of this research was to investigate the efficacy of novel chemical controls and physical exclusion on SWD in primocane raspberry fruit. For our first set of experiments, we conducted a series of laboratory bioassays to test twenty-five potential pesticide treatments. We measured the effects of these treatments on SWD adult mortality, oviposition, larval and pupal development, and adult emergence. This information was used to guide a follow up study testing thirteen of the most promising treatments on SWD mortality and infestation in the field. Results showed that the broad spectrum conventional and organic controls provided the best SWD control, however botanical products provided some protection against infestation. Additionally, there is increasing interest in using physical exclusion and high tunnel production as a pest management tool, particularly since many growers already use high tunnels for season extension and improved fruit quality. Our second set of experiments investigated how plastic-covered, enclosed tunnels affected fruit yield and quality, as well as SWD infestation. We collected data on yield, proportion of marketable and unmarketable fruit, berry size, total soluble solids (°Brix), proportion of infested fruit, and the microclimate characteristics inside of the plots. The objective of these experiments was to improve integrated pest management strategies for SWD and provide recommendations for both organic and conventional growers for sustainable management of this invasive pest.