Aphids as Beneficial Insects? Using a Fire Ant – Aphid Interaction for the Sustainable Management of Insect Pests in Southern Cotton

Project Overview

GS03-023
Project Type: Graduate Student
Funds awarded in 2003: $7,040.00
Projected End Date: 12/31/2004
Region: Southern
State: Alabama
Graduate Student:
Major Professor:
Micky Eubanks
Auburn University

Annual Reports

Commodities

  • Agronomic: cotton

Practices

  • Crop Production: application rate management
  • Pest Management: biological control, economic threshold, field monitoring/scouting, integrated pest management
  • Production Systems: agroecosystems, holistic management

    Abstract:

    Understanding the effects of fire ants on crop production is crucial because fire ants are extremely abundant on farms in Alabama and other southern states and continue to spread into California and up the east coast. Fire ants have strong ecological effects because they reach extremely high densities and are voracious predators that consume large numbers of other arthropods. Some effects of fire ants may be beneficial to crop production because they may attack and suppress plant pests not currently controlled by natural enemies (predators and parasites). Some effects of fire ants, however, are likely to harm crop production because they may suppress populations of natural enemies that currently control economically serious pests. Although fire ants have been studied for many years, it is currently difficult to predict in which systems or under what conditions the effects of fire ants are likely to benefit or harm crop production. This project will take a novel experimental and modeling approach to understand and predict the effects of fire ants on crop production. Our most recent work suggests that the effects of fire ants on crop production may be predictable. We have found that fire ants have more intense and pervasive effects on pests when aphids are abundant. Fire ants and aphids form a mutualistic relationship in which fire ants vigorously protect aphids from predators and competitors (other pests) and, in exchange, aphids supply fire ants with a sugar-rich excretion called honeydew. Because cotton aphids cause very little damage to cotton plants, cotton aphids may result in increased cotton yield when they stimulate fire ant predation of more serious pests like caterpillars. We propose to test this hypothesis by developing and validating a quantitative model that will predict the effect of aphid – fire ant mutualisms on cotton yield. This model will be easily adapted to other agricultural as well as naturally-occurring systems to predict the effect of ant – aphid mutualisms on crop yield/plant fitness.

    Introduction

    The goal of this project is to develop and test a model that accurately predicts the effects of fire ants on crop yield. Understanding the effects of fire ants in agricultural systems is critical because fire ants infest virtually all crops in Alabama and other southern states and are continuing to spread westward into California and northward along the east coast. Fire ants have strong ecological effects in agricultural systems because they reach extremely high densities and are voracious predators that consume large numbers of other arthropods. Some effects of fire ants may be beneficial to crop production because they may attack and suppress plant pests that are not currently controlled by natural enemies (predators and parasites). Some effects of fire ants, however, are likely to harm crop production because they may devastate populations of natural enemies that currently control economically serious pests. Although fire ants have been intensively studied for many years, we do not currently have the knowledge to predict in which systems or under what conditions the effects of fire ants are likely to benefit agriculture and in which systems or under what conditions the effects of fire ants are likely to harm agriculture. This project will take a novel experimental and modeling approach to understand and predict the effects of fire ants.

    Project objectives:

    Test the hypothesis that the aphid-fire ant mutualism results in decreased damage to cotton from caterpillars and increased yield.

    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.