The 1993 Mid-America Tomato Integrated Pest Management (IPM) Program served processing tomato growers in three states -- Ohio, Michigan and Indiana. The aim of the project is to reduce the fungicide and insecticide inputs by monitoring insect populations and environmental conditions conducive to disease.
The TOM-CAST portion of the Mid-America program utilizes hourly temperature and leaf wetness data collected at 10 stations in Ohio, Michigan, and Indiana to provide fungicide scheduling information for tomato growers. The information (regional Disease Severity Values or DSV) is updated 6 days per week and made available to growers, field representatives, researchers and extension agents via a toll-free phone message service. Insect scouting reports, summaries of pheromone trap catches of cabbage looper, variegated cutworm, and tomato fruitworm moths, and computer predictions of Colorado potato beetle emergence were also included on this phone message. The phone service was based at The Ohio State University (Columbus) and received an average of 11 calls per day during the peak tomato growing months of June through September.
As part of the insect management portion of the Mid-America program, a comprehensive IPM program was tested at eight commercial tomato farms located in Ohio, Michigan and Indiana. At each farm, a 20-acre field was divided into an IPM half and a conventional half. Forty plants on both the IPM and conventional halves were scouted by Ohio State University personnel, and insecticide applications to the IPM half were made based on preliminary OSU spray guidelines (see Table). Fungicides were applied to the IPM half based on the TOM-CAST system. The conventional half was sprayed on the growers own spray program for both insecticides and fungicides.
| Pest | Threshold/Guideline | Plant Growth Stage |
|---|---|---|
| Colorado Potato Beetle | >1.0 adult per plant | Seedling only |
| Variegated Cutworm | >1 caterpillar per 20 plants | >= Green Fruit |
| Cabbage Looper | >1 caterpillar per plant | >= Green Fruit |
| Tomato Fruitworm | >1 caterpillar per 20 plants | >= Green Fruit |
| Flea Beetles | >4 per plant | Seedling only |
| Aphids | >1 per leaf | All stages |
| Tomato/Tobacco Hornworms | >1 caterpillar per 30 plants | All stages |
The yield of good red fruit was not significantly different between the IPM (19.4 tons per acre) and conventional (23.8 tons per acre) fields. These yields are similar despite the fact that three IPM fields had reduced yields from severe flooding, while no conventional fields were flooded.
Total fruit mold (ground rot, anthracnose and early blight) was significantly higher in the IPM (18.9%) than the conventional (12.5%) fields. Severe flooding contributed to increased mold counts in three IPM fields.
Variegated cutworm, tomato fruitworm or hornworm damaged fruit averaged 1.3% of yield (pre-sort) for the IPM fields compared with 1.5% for the conventional fields. Stink bug damaged fruit averaged 1.6% of yield (pre-sort) for the IPM fields compared with 1.3% for the conventional fields. Both of these differences were not statistically significant.
To determine if the IPM program was successful in reducing pesticide use, spray records were requested from all cooperators. Thus far, 5 of 8 growers have submitted written spray records for the 1993 season. On average, growers made 1.2 more insecticide and 1.0 more fungicide applications on the conventional half than on the IPM half. Based on interviews, this trend is expected to continue on the 3 remaining fields. Interviews have also indicated that at least one grower "cheated" and reduced insecticide applications on the conventional half based on OSU recommendations for the IPM half. This particular grower averaged 6-7 insecticide applications per field in previous years.
These preliminary results indicate that field scouting and OSU insect spray guidelines substantially reduced insecticide applications and maintained good tomato quality, when compared with conventional grower practices. However, further research is needed to streamline and improve certain scouting procedures; particularly for variegated cutworm and stink bugs. Pheromone trapping showed potential as a practical method for monitoring initial and peak variegated cutworm moth activity. The test results demonstrated that the TOM-CAST system reduced fungicide applications and maintained competitive yields.
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