Tomato IPM Field Demonstrations in Alabama

Introduction

Fresh market tomatoes are an important crop in Alabama, with an estimated annual value of $18 million. Several plant diseases and insect pests significantly affect tomato production in the state. Attempts by growers to control these pest often result in the heavy use of pesticides. One way for growers to reduce pesticide usage while maintaining profitability is to incorporate Integrated Pest Management (IPM) strategies into their production program. IPM emphasizes preventative methods that provide economical, long-term solutions to pest problems while minimizing hazards to human health and to the environment.

In 1996, a survey was conducted to determine the levels of adoption of tomato IPM in the Southeast (Bauske, Zehnder, Sikora, & Kemble, 1998). The results of this survey indicated that 65% of Alabama growers and 66% of Alabama acreage were in the medium and high IPM use categories. However, none of the growers surveyed employed a scouting service, and most had not been trained in pest scouting. In addition, none of the respondents had used TOMCAST, a weather-timed fungicide spray program that was shown previously to be effective and economical for use on fresh-market tomatoes in Alabama (Sikora, Bauske, & Pitts, 1994a; Sikora, Bauske, Zehnder, & Hollingsworth, 1994b).

Alabama growers were interested in adopting insect and disease scouting and the TOMCAST program. However, they expressed concern about the physical and economic constraints of applying fungicides and insecticides independently on an "as needed" basis and questioned if there would be a financial gain associated with the extra work. To address these issues, the Alabama Tomato IPM Program was compared with conventional pest management practices in on-farm demonstrations in 1997 and 1998. The program was funded by the USDA Southern Region IPM Program.

Field Demonstrations

Demonstrations were conducted in Geneva County, Alabama. Seven growers participated in the 2-year study. Each grower set aside a 1-acre tomato field for the purpose of comparing the IPM program with their conventional pest management practices. On half of the field, each grower followed his conventional pest management program (conventional field section), whereas on the other half (IPM field section), the grower followed the IPM program designed by Auburn University. The IPM program consisted of a twice-a-week insect/disease scouting program combined with TOMCAST.

In the conventional field sections, growers typically applied the insecticides dimethoate and esfenvalerate for thrips and fruitworm control, respectively, weekly throughout the season. The insecticides were usually mixed with a fungicide such as chlorothalonil or mancozeb for control of foliar blight diseases.

The Auburn University-trained scout visited the IPM field sections twice a week from transplanting through harvest. The scout examined 50 plants/field section for the presence of diseases and/or insect pests. A report was submitted to the grower after each scouting session detailing the occurrence of diseases and insect pests and providing a pesticide recommendation when necessary. Cooperators based their fungicide spray schedule on recommendations based on TOMCAST provided by AWIS Weather Services (Auburn, Alabama). During the season, the fungicide spray program was adjusted accordingly by the scout based on which diseases were observed in the field.

At the end of the season, the number of pesticide applications used in the conventional and IPM field sections were compared, and a budgetary economic analysis was performed. Actual expenses incurred for both systems were averaged across growers and years.

Results and Impacts

1. There was no difference in fruit production or fruit quality between the programs.
2. Growers saved $34.12/acre when using the IPM program; there was a 47% reduction in the cost of insecticides and a 27% reduction in the cost of fungicides.
3. Growers made four fewer insecticide applications with the IPM program, compared to their conventional program.
4. Growers averaged 4.8 applications of dimethoate for thrips control with the IPM program, in contrast to 9.7 applications in their conventional program.
5. Growers averaged 3.5 applications of esfenvalerate for fruitworm control, in contrast to 8.8 applications in their conventional program.
6. Growers averaged 8.8 fungicide applications with the IPM program, in contrast to 12.4 applications with the conventional program, and there were no differences in severity of foliar diseases between the programs.
7. Growers following the conventional program averaged 12.3 trips through the field to apply pesticides, while growers following the IPM program averaged 12.7 trips. The savings in pesticide costs using IPM offset the additional cost resulting from the extra trip through the field.
8. The cost of TOMCAST via AWIS would be $4.77/acre for a growing season for an averaged size farm (22 acres) in Alabama.
9. The cost of scouting tomatoes in Alabama will range from $25-45/acre per season.
10. The participating growers were enthusiastic about the IPM program and requested availability of this approach on an annual basis.

Summary

The goal of the project was to provide the growers of Alabama with a clear vision of the benefits of a tomato IPM program. Currently, there are no trained field scouts for tomatoes in Alabama, nor is there a tomato organization that could support such a service. The growers who cooperated in this project have asked a private cotton scouting company to add tomatoes to their scouting service. This scouting service will receive TOMCAST directly from AWIS via the Internet, resulting in improved timing of fungicide and insecticide applications and reduced costs to the grower.

References

Bauske, M., Zehnder, G. M., Sikora, E. J., & Kemble, J. (1998). Southeastern tomato growers adopt integrated pest management. HortTechnology 8: 40-44.

Sikora, E. J., Bauske, E. M., & Pitts, J. (1994a). Evaluation of fungicides using fixed and weather-timed spray schedules for early blight control of fresh market tomatoes. Fungicide and Nematicide Tests 49: 173.

Sikora, E. J., Bauske, E. M., Zehnder, G. W., & Hollingsworth, M. H. (1994b). Evaluation of low-input fungicide spray programs for control of early blight on tomatoes. Auburn University Agric. Exp. Sta. Highlights of Agricultural Research 41:15.