Plant Pathology Infobytes

June 29, 1999
Tomato Water Wilt Common Following Excessive Rainfall

Some areas of the state received several inches of rainfall over a short time period during the past week. This has created conditions favorable for the development of a physiological disease of tomatoes referred to as "water wilt." Although water wilt isn't confined to tomatoes, and may show up on peppers, beans, and other garden plants, tomatoes seem to be more sensitive to this problem - especially when grown in poorly drained soils.

The first sign of water wilt is a slight wilting of foliage in the top of plants following several inches of rainfall within a short period. The wilt continues, and the entire plant may collapse within six to twelve hours. Plants growing in well-drained soils generally recover within a day; however, tomato plantings in heavy, poorly drained soils may not be so fortunate. As a result of poor drainage, roots may be exposed to waterlogged soil conditions for several days, and this often leads to death of tomatoes or other affected garden plants.

While it is true that tomato plants love water, too much of a good thing leads to the previously described problem. Under soggy soil conditions, tomato roots use up available supplies of gaseous soil oxygen, which is replaced by toxic levels of carbon dioxide. Roots of tomato plants can't survive without oxygen, and extended periods without this essential element lead to tomato plant death.

If saturated soils dry quickly enough, tomato plants suffering the effects of "water wilt" may survive. However, gardeners shouldn't count on plant survival, since in most cases root systems have been damaged beyond recovery and plant replacement is often necessary. Replanting of damaged plants in a new garden location is rarely successful, since damaged roots are frequently attacked by Pythium or Phytophthora root rot and other soil diseases.

"Water wilt" is a good reason to think about making raised-row gardening part of your vegetable production program. Visit the County Extension Office for a copy of "The Garden Tabloid." Raised-row gardening and other timely gardening topics are covered in this free Extension Service publication.



Written by the late Dr. Frank Killebrew

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