IPM Tips for Tomato Disease Control in High Tunnels
Published: March 1, 2011
Temperature and humidity are key environmental factors that need to be monitored constantly in high tunnels (HT) to avoid conditions that are conducive to disease development. The following IPM tips can help reduce disease development in HT tomatoes:
- Use disease-resistant varieties. Mountain Magic (indeterminate) and Plum Regal
(determinate) are resistant to early and late blight. Fruits are crack-resistant.
- Raised beds, coupled with plastic mulch and drip irrigation tape buried beneath each bed, improves growth, fruit quality and disease and insect pest resistance.
- Maintain optimum crop growth by providing adequate nutrients and soil moisture. Soil moisture tension should be maintained between 10 and 20 centibars; irrigate when soil moisture tension exceeds 20 centibars, irrigation should occur. Use Tables 10 & 11 from the Midwest Vegetable Production Guide for Commercial Growers to estimate centibars in the absence of a tensiometer.
- Limit the length of time above 90%relative humidity (RH) as foliar diseases are favored by high RH (above 85%). Remove suckers and (if possible once in fruit production) older leaves as they are more susceptible to fungal infections.
- Control weeds (e.g. horsenettle and other species in the tomato family) in and around the high tunnel.
- DON'T OVER-FERTILIZE. It may result in higher incidence of certain diseases (e.g., early blight), increases in pest pressure (e.g., two-spotted spider mites, aphids, thrips), and in excessive salt build up in the soil (over time).
- Practicing good sanitation is critical. Always remove diseased tomato plants or plant parts, sterilize plant stakes prior to reuse, and clean tools and implements frequently to prevent transporting problems between fields
- Correct disease identification is critical for good disease control decisions. It saves time and money. Keep in mind that some diseases are difficult to manage once they become established. However, if an early infection is identified, cultural tactics, fungicides or bactericides can be used to reduce disease spread. Always apply a product according to label directions at the first sign of disease.