Location: Stored Product Insect and Engineering Research
Project Number: 3020-43000-034-020-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Sep 1, 2022
End Date: Aug 31, 2025
Over 1.3 billion tons of postharvest commodities amounting to over $100 billion US dollars are annually lost after harvest with damage caused by stored product insects being a major factor. Economic losses from insect infestations in milled and finished food products can be even greater as product values increase significantly as they move through the supply chain. Climate change has led to increased crop yield losses worldwide and could compound insect pressure in post-harvest situations, resulting in even greater losses into the future. The mean daily temperature and number of high temperature days (>37C) is projected to rise, which may impact the ability of stored product insects to adapt to other stresses, such as insecticides. Evidence in many organisms suggests that exposure to environmental stress (such as temperature) can prime an individual’s ability to withstand subsequent stresses. Thus, warming trends associated with climate change could facilitate insecticide tolerance in this important group of insects. Furthermore, in populations that already have resistance, climate change could alter tolerance to insecticide as fitness costs of insecticide resistance shift. Thus, the objectives of this agreement are to assess the impacts of climate change on 1) current integrated pest management (IPM) strategies against insecticide resistant and susceptible stored product pests, and 2) the biology, physiology, population growth, and life history of these pests.
For the first objective, we will test the efficacy of common commercial pesticides, long-lasting insecticide netting or fumigants on lethal and sublethal effects of at least two different species of stored product insects under different temperature scenarios to simulate current climate conditions and those associated with climate change, which will include continuously rearing the insects at higher temperatures and/or periodically exposing the insects to high temperatures to simulate higher numbers of high temperature days. Assays will be performed on susceptible and resistant populations of stored product insects. Impacts on mortality and knockdown will be assessed and sublethal impacts on dispersal and movement will also be measured. For the second objective, we will assess the impacts of current climate conditions and the different climate change scenarios described above on population growth and physiology on resistant and susceptible populations of the same stored product species. Fitness under all climate scenarios will be assessed in both the presence and absence of insecticide pressure. Various fitness parameters that will be assessed include fecundity, mortality, development time, hatch rate, etc. These life history parameters can be used to develop predict model for impacts of climate and insecticide pressure on population dynamics, which can allow us to ascertain the efficiacy of these insecticdes over time. In addition, RNA-Seq coupled with detoxification enzyme assays will be used to evaluate the impacts of insecticide exposure, climate change, and the interaction of these two factors on insect physiology.