Biorational approaches for management of bacterial wilt and bacterial spot on tomato

Project Overview

LS06-192
Project Type: Research and Education
Funds awarded in 2006: $150,000.00
Projected End Date: 12/31/2010
Region: Southern
State: Florida
Principal Investigator:
Dr. Jeffrey Jones
University of Florida

Annual Reports

Commodities

  • Vegetables: tomatoes

Practices

  • Education and Training: demonstration, extension, on-farm/ranch research, workshop
  • Farm Business Management: budgets/cost and returns
  • Pest Management: biological control, biorational pesticides, botanical pesticides, chemical control, cultural control, integrated pest management, mulching - plastic
  • Sustainable Communities: sustainability measures

    Abstract:

    We have identified several alternative approaches for improved control of bacterial spot and bacterial wilt. These approaches have either relied on finding alternative control strategies that rely on totally on environmentally-friendly control strategies in the case of bacterial wilt or in the case of bacterial spot of tomato, we have identified strategies for applying combinations of chemicals and/or biological control agents. For bacterial wilt, we determined that the application of thymol and acibenzolar-S-methyl when was used together in field conditions to control bacterial wilt on moderately resistant tomato cultivars will not have a negative affect on the tomato production. The combination of both products numerically increased the fruit yield and decreased the disease incidence for the susceptible cultivar. For bacterial spot, we looked at reduced rates of actigard. In the reduced rate experiment 1/10 X rate of Actigard effectively controlled bacterial spot on the tolerant line (8314) compared to the standard copper bactericide treatment early in the experiment; however, as the experiment continued, Actigard provided no improved disease control. The tolerant genotype had significantly less disease than the susceptible genotype (Bella Rosa) at the end of the experiment. In general by the end of the experiment none of the treatments in the tolerant variety were significantly different. Yield for all treatments were not significantly different. In a separate reduced risk experiment twice weekly applications of bacteriophage provided significantly better disease control than the standard copper-mancozeb treatment. Growers may wish to consider using bacteriophages as a treatment for bacterial spot of tomato as an alternative to the standard copper-mancozeb treatment. We also provide evidence for bacterial spot disease control with a phosphorous acid salt. Clearly more work is necessary for finding improved strategies for disease control of bacterial spot and bacterial wilt; however, we do provide information for improved control strategies that in some cases growers are beginning to accept.

    Project objectives:

    1. To develop strategies in integrated management of bacterial wilt:

    a. Evaluate the efficacy and application methods of new biofumigants and reduced risk compounds in control of R. solanacearum on tomato under greenhouse and field conditions.

    b. Determine efficacy of the SAR inducer, Actigard, in reducing bacterial wilt on susceptible tomato cultivars under field conditions at different inoculum levels, and evaluate integrated effectiveness and economics of field application of Actigard, biofumigant (thymol), and commercial tolerant or resistant tomato genotype (FL 7514, BHN 669) in the management of bacterial wilt.

    c. Using the data obtained in objectives 1a and 1b to develop and implement best management strategies for bacterial wilt on tomato in naturally infested commercial tomato fields. On-farm research and demonstrations will be conducted in collaboration with growers and extension agents in north Florida and southern Georgia.

    2. To optimize integrated management of bacterial spot with the SAR inducer Actigard, PGPRs and bacteriophages.

    a. Determine if lower rates of Actigard can be applied to enhance disease control without affecting tomato yield and identify resistant lines to determine if they respond to PGPRs.

    b. Determine the effects of modified application strategies of the SAR inducer (Actigard) and PGPRs in combination with bacteriophages.

    c. Combine the best strategies in 2a and 2b for management of bacterial spot in field experiments to achieve maximum reduction of the disease and copper bactericide application. On-farm research and demonstration will be conducted in north Florida and southern Georgia and economic benefits will be analyzed.

    3. To determine, through Cost Benefit Analysis of each field trial, the management strategies yielding the greatest financial returns to the grower.

    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.