Insecticide use in cover crops: Understanding impacts at a field scale

Project Overview

ONC20-077
Project Type: Partnership
Funds awarded in 2020: $39,906.00
Projected End Date: 06/01/2022
Grant Recipient: University of Nebraska Eastern Nebraska Research and Extension Center
Region: North Central
State: Nebraska
Project Coordinator:
Dr. Justin McMechan, Ph.D., D.P.H.
University of Nebraska Eastern Nebraska Research and Extension Center

Commodities

  • Agronomic: corn

Practices

  • Crop Production: cover crops
  • Education and Training: extension, on-farm/ranch research
  • Natural Resources/Environment: biodiversity
  • Pest Management: integrated pest management

    Abstract:

    The use of cover crops has increased as a sustainable means of improving soil health and suppressing weeds in agricultural systems. However, recent reports have shown a potential risk of insect pests transitioning from cover crops to corn in the Midwest due to the timing of cover crop termination relative to corn planting. Unexpected losses from insect pests in cover crop systems have resulted in some farmers adopting the use of tank-mixed insecticides at cover crop termination as a preventative strategy to minimize pest pressure. To date, there was not enough information to help farmers make an informed decision on if and when they should use insecticides in a cover crop-corn system. This project formed collaborations with four corn-soybean farmers in eastern-Nebraska, two of which collaborated on a previously funded NC-SARE graduate student grant. Our study aims to better understand the impact of insecticide application as a preventive strategy against arthropods, either at cover-crop termination or when the cover crop is decomposing. Our finding indicates that preventive insecticide applications are not needed, highlighting the importance of scouting for pests before making a management decision. Moreover, we hypothesize that cover-crop biomass might create a physical barrier protecting arthropods below the cover-crop canopy.

    Project objectives:

    On-farm field studies were conducted across eight site-years in eastern Nebraska to evaluate (1) insecticide timing of application impact on arthropod activity in the following corn and (2) identify the best arthropod-management strategy to assist farmers in making profitable and sustainable decisions. We hypothesized that if cover-crop pests are present, such as wheat stem maggot, would be reduced with late insecticide application. We hypothesized that the addition of any preventive insecticide application would reduce arthropod activity and would not increase corn yields unless significant pest pressure occurred.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.