Integrating Biological Control into Pecan Weevil Management: A Sustainable Approach

2003 Annual Report for LS03-153

Project Type: Research and Education
Funds awarded in 2003: $217,500.00
Projected End Date: 12/31/2006
Region: Southern
State: Georgia
Principal Investigator:

Integrating Biological Control into Pecan Weevil Management: A Sustainable Approach


The goal of this project is incorporate biological control methods into a sustainable pecan weevil management system. Specifically, we are endeavoring to enhance the efficacy and persistence of a natural biological pesticide, i.e., the fungus Beauveria bassiana. In the first year of the project we have conducted laboratory studies to compare the longevity of various fungal isolates in soil. Additionally, we have conducted preliminary field-testing of the fungi with a soil amendment (compost) and novel formulation (oil) to determine ability to enhance biocontrol efficacy. Our results indicate that the fungi differ significantly in their inherit abilities to persist in soil. We observed no benefit from addition of compost in enhancing fungal persistence. However, we have observed that an oil formulation of the fungus (applied to the pecan trunk) may offer substantial potential increasing efficacy and suppressing pecan weevils.

Objectives/Performance Targets

  • Our overall goal is to reduce reliance on chemical insecticides by incorporating biological control into a sustainable pest management program for C. caryae. Specific objectives are to:
    1. Enhance persistence of C. caryae control with Beauveria bassiana by one or more of the following:
    A. Selecting superior B. bassiana strains.
    B. Addition of soil amendments to improve B. bassiana persistence.
    C. Developing improved formulations.

    2. Determine the optimum area of B. bassiana application

    3. Conduct feasibility and economic analyses to determine the potential of incorporating B.
    bassiana into an integrated pest management system.

    4. Extend the project findings to grower clientele.


Research to date has set the basis for moving forward with the project. We have determined inherit differences in fungal strain's ability to persist in soil, screened several formulations for UV tolerance, and conducted preliminary field tests to determine methods of enhancing biocontrol efficacy. Future intense laboratory and field tests will screen a variety of soil amendments and formulations for fungal enhancing potential. Field tests will determine the most promising combinations of fungal strain, formulation and amendment.

Impacts and Contributions/Outcomes

Impact of the project is mostly yet to come (two more years of the project remain). We anticipate that methods to enhance natural fungal biopesticides will be developed, and these methods will facilitate the utilization of biocontrol for pecan weevil suppression as well as for other important insect pests.