Boll Weevil Regional Management

Introduction

Management of arthropod pests on cultivated crops in the United States has evolved dramatically over the last 20 years. Field specialists increasingly rely on economic thresholds, quantitative sampling procedures, and predictive models to determine the proper timing of control measures. Consequently, in many crop systems the amount of pesticides used, and thus the amount entering the environment, is being reduced.  However, there exists at best an incomplete understanding of

the complexity by which factors such as weather and overwintering vegetation influence the seasonal population dynamics, regional movement, and interaction of agricultural pests with their primary host crops. Because many agriculturally important arthropods are highly mobile and readily disperse across wide geographical areas, rather than traditional field level management, a more appropriate approach may be one that addresses arthropod management on a regional basis.

Our cotton boll weevil research incorporates the technology of geographic information systems (GIS) with crop and pest modeling in a novel approach to IPM. GIS can provide detailed information on arthropod pest populations with respect to location and spatial extent of host crops and alternate vegetative habitats, and related analyses can quantify the degree to which arthropod densities are a

function of weather, pesticide use, and proximity to alternate vegetation. Mechanistic crop-arthropod simulation models when coupled to spatially-referenced data can be used to examine in detail, the interactions between arthropod populations and their host crops at a field and regional level for a range of potential and existing management strategies. This approach can provide objectively-criteria with which to optimize the management of highly dispersive pests over wide geographic regions.

The goal of our project is to develop a quantitative understanding of the local and regional population dynamics of the boll weevil, Anthónomus grándis Boheman, in cultivated cotton, Gossypium hirsutum L, as affected by proximity to overwintering vegetation, winter weather, and management strategies. To accomplish this goal, the following objectives are proposed.

1) To generate critical data on biological and environmental parameters that influence boll weevil Winter survival and Spring emergence. 2) To quantify the major geographical and environmental parameters that influence boll weevil regional abundance. 3) To examine in detail, the regional and temporal dynamics of the boll weevil, in order to quantify the economic and environmental impact of potential regional management strategies, including those appropriate for environmentally sensitive areas and endangered species zones.

Our long range objective is to significantly reduce boll weevil infestations in cotton and improve environmental quality by lowering the levels of insecticides used in cotton growing regions.

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