Avoid planting tomatoes in the same field year after year. Rotating to a nonhost crop can significantly reduce pest populations in the field. The table below provides information on nonhost crops that interrupt certain tomato-associated pathogen, nematode, and weed cycles.
For winter annual weed control, choose wheat or small grains in fall and control weeds in these crops with a suitable herbicide. Consider managing summer annual weeds by growing corn in rotation with tomato. Use selective herbicides and cultivations.
Currently, research is lacking in California about how many years tomatoes can be continuously planted in non-problematic fields with drip irrigation. Preplant applications of fumigants or fungicides chemigated through the drip system can extend continuous tomato production.
| Pest type | Suggested rotation cycle in years | Nonhost crop options and other comments |
|---|---|---|
| Diseases | ||
| Verticillium wilt | 3 | Small grains, corn |
| Phytophthora root rot | 1 | Cereals for severe infestations |
| Bacterial spot | 1 or more | Nonsolanaceous crops |
| Bacterial canker | 1 or more | Nonsolanaceous crops |
| Fusarium wilt | 2 or more | Crops other than tomato |
| Southern blight | 3 | Small grains |
| Corky root rot | 2 or more | Small grains, corn |
| Other pests | ||
| Root-knot nematode | — | Use resistant tomato varieties and other nonhosts |
| Weeds | 1 or more | See SPECIAL WEED PROBLEMS |
| Dodder | — | Use tolerant tomato varieties or grass crops |