Cause A physiological response by tomato plants to fairly extreme changes in soil moisture levels is thought to be associated with physiological leafroll. Prolonged dry soil conditions, high nitrogen levels, a phosphorus deficiency, severe pruning while plants are under dry soil conditions, or wet soil conditions with accompanying hot temperatures have also been associated with this problem. The severity of symptoms depends on the variety of tomato; high-yielding and indeterminate varieties appear to be more sensitive than other types of tomato. Physiological leafroll does not affect fruit yield or quality.
Symptoms The edges of many but not all leaves on affected plants roll upward and inward, sometimes the leaf sides touch or overlap. The leaf rolling can be transient or may persist throughout the rest of the growing season.
- Plant determinate tomato varieties.
- Maintain a well-timed irrigation schedule that prevents overly-dry and overly-wet soils.
- Practice a balanced, appropriate fertilizer regime.
- Protect plants from temperatures above 95°F.
- Avoid excessive pruning of indeterminate tomato varieties.
Reference The Pacific Northwest Vegetable Extension Group. 2011. Physiological Leaf Roll of Tomato. Pacific Northwest Extension publications: PNW616.