Patricia M. Arledge, Sharpe, Kenneth W.
News Article for May 7, 2012:
We seem to be in a pattern of when it rains it pours, gully washer style. That makes it hard on tender vegetable plants and accompanying winds in those thunderstorms have knocked corn and other plants over.
Corn will usually straighten itself up after the sun comes back out but most of the commercial vegetable producers have gone to system of staking and tying peppers and eggplants to prevent them from being blown over.
While making farm visits this past week I saw a few tomatoes being picked already, again several weeks earlier than most years. Those rewards were for the risk takers who planted early betting that it would not frost and they won.
I have seen a number of incidences of what is called tomato leaf roll. The leaves on the tomato plant will roll up inward like a cigar. This usually starts on the bottom leaves and those leaves become leathery and firm. Ms. Carrie Parker asked me what caused tomato leaf roll. Even though I knew the answer I decided to investigate it for any updated information I could find.
Tomato leaf roll has always been characterized as a physiological disorder. That means that the cause is environmental and is not a disease. A quick review of the scientific literature seems to indicate that is still the common belief. Tomato leaf roll appears to be caused by environmental stress and is reported to occur all over the United States.
I have had tomato leaf roll once myself and it did not seem to affect the yield of the tomatoes but it did leave the tomato fruit uncovered and vulnerable to sun scald.
The literature reports several conditions that seem to be positively correlated with tomato leaf curl. There does seem to be fewer problems with determinate or bush type varieties and more problems with vining or indeterminate varieties. High moisture soils and low moisture soils are stresses that seem to make this condition worse and especially when you have high temperatures at the same time. Heavy pruning and cultivation that disturbs the root system have also been identified as contributing factors as has excessive nitrogen applications.
Varieties that are selected for highest production tend to get tomato leaf curl at a greater frequency than lower yielding varieties.
Since this condition is not a disease there is no fungicide treatment to cure the problem. Follow recommended growing practices and avoid environmental stresses, where possible to help reduce the incidence and severity. Plant tomatoes in a well-drained soil. Fertilize according to soil test recommendations and do not over fertilize with nitrogen. Avoid close cultivation that may disturb the plant root system. Maintain uniform soil moisture and mulch plants with either plastic or organic mulches.