Location: Pest Management Research
Project Number: 3032-22000-019-000-D
Project Type: In-House Appropriated
Start Date: Oct 1, 2020
End Date: Sep 30, 2025
OBJECTIVE 1: Determine the role of rangeland insects, particularly grasshoppers, on rangeland ecosystem function and production. OBJECTIVE 2: Identify climatic and biotic ecological drivers of pest population dynamics of wheat stem sawflies, grasshoppers and Mormon crickets. Subobjective 2A: Develop and verify growing degree day models of Mormon cricket embryonic development and hatch. Subobjective 2B: Investigate the duration that Mormon cricket eggs remain in egg beds. Subobjective 2C: Identify causes of Mormon cricket mortality in egg beds, including temperature and desiccation. Subobjective 2D: Identify cues that cause Mormon cricket females to lay eggs that break diapause and hatch after one, two, or several winters to improve applicability of Mormon crickets as high protein component of feed and food. Subobjective 2E: Identify vegetation variables (e.g. increase in invasive grasses) associated with shifts in grasshopper abundance and community structure. Subobjective 2F: Identify forage quality effects on grasshopper performance and spectral bandwidth differences in vegetation. OBJECTIVE 3: Develop predictive models of rangeland and crop insect pest distribution, population growth and impact to allow land managers to address outbreaks at earlier stages and optimize control efforts. Subobjective 3A: Model embryonic development and hatch of Mormon crickets across elevations in the Western U.S. Subobjective 3B: Model centers of endemism in Mormon cricket populations based on multi-annual life cycles and topographic variation in the Western U.S. Subobjective 3C: Investigate the effects of annual to decadal scale weather patterns and spectral vegetation indices on pest insect outbreaks. Subobjective 3D: Model the effect of El Niño Southern Oscillation on plant primary productivity and grasshopper outbreaks in the Western U.S. OBJECTIVE 4: Design sustainable approaches (e.g. roadside and conservation plantings, landscape diversification, rangeland fire and grazing management) to manage key crop and rangeland insects, such as wheat stem sawfly, alfalfa weevil, pea aphids, grasshoppers, and their natural enemies. Subobjective 4A: Examine the impact of rangeland management practices on grasshopper populations. Subobjective 4B: Identify factors enhancing Bracon cephi abundance and efficacy in controlling wheat stem sawfly populations. Subobjective 4C: Identify field and landscape drivers of alfalfa weevil population dynamics and biological control.
Grasshoppers, Mormon crickets, wheat stem sawfly, and alfalfa weevil significantly damage rangeland and crop productivity in the Central and Western United States. Grasshoppers and Mormon crickets consume ~$1.7 billion of forage annually in the U.S. and wheat stem sawfly causes ~$250-350 million in crop damage annually. These pests are high priority targets for ranchers, farmers and federal and state land managers, since current control strategies are inadequate, costly and/or result in unacceptable environmental impacts due to the historical reliance on broad spectrum insecticides. The long-term goal of this proposed research is to develop innovative, environmentally sound and sustainable management alternatives for control of these pests which currently lack sustainable control measures. To achieve this end, we will pursue research to broaden the ecological knowledge of these pests, improve pest risk assessments, and enhance prevention of pest outbreaks. We will develop a sound understanding of pest impacts on rangeland production and determine climatic and biotic drivers that cause crop and rangeland pests to exceed economic thresholds in the Great Plains. We will design sustainable habitat and landscape approaches to manage these pests and their natural enemies. Pursuing research in ecology, forecasting and prevention will provide the foundational knowledge necessary to achieve the ultimate goal of developing ecologically-based and economically practical management strategies that reduce economic impacts and promote food security, while decreasing environmental impacts of control measures. We will communicate our results through meetings, publications and presentations targeting land management agencies, farmers and ranchers, academic societies, industry and state extension services.