One adjective I’d use to describe gardeners is “persistent.”
I mentioned my great-grandmother a few weeks ago. She was an active gardener up until 90. Her son, V.J. Hill, passed away last fall at 95. He was still planting his garden until a couple years ago. This February, I took soil samples for my 92-year-old great-uncle Glancia’s vegetable garden.
Maybe gardening and longevity are linked? Gardening is often suggested as good exercise and a great way to reduce stress.
Stress-free, however, is not how I’d describe growing tomatoes!
To a gardener, nothing is more stressful than seeing your healthy tomato plant die overnight or the perfectly shaped tomato have a rotten spot on it. So many potential problems seem to be lurking in our gardens waiting for the right opportunity to ruin our tomato crop.
Lately I’ve had several questions about tomato wilt. Two of the most common wilt diseases we experience are southern bacterial wilt and southern blight. Both diseases lead to a quick demise of your beloved tomato plants, leaving you wondering what went wrong.
Southern bacterial wilt is caused by the soil-borne bacterium, Ralstonia solanacearum, and favors hot weather and wet soil conditions. Initially, plants show signs of wilting that many mistake for needing water. Plants may seem to recover overnight, only to be followed by rapid wilting and death.
This wilt is due to bacteria clogging the xylem tissue of the plant, which stops water movement from the roots to the leaves. A quick test for bacterial wilt is to plant the cut stem of the tomato plant in a glass of water and look for a cloudy substance to stream out of the stem into the water. This is the bacteria oozing out of the plant.
Southern blight is caused by a soil-borne fungus, Sclerotium rolfsii. Like bacterial wilt, it favors warm weather and wet soil conditions. The pathogen can infect any part of the plant at or just below the soil line. This includes low hanging tomatoes. Initial symptoms include discolored lower leaves and wilting. As the disease progresses, plants collapse and die.
Characteristic signs of the fungus are a thick, coarse, white mold on stem cankers and fruit and small, round, brown sclerotia (resting structures). These are very small tan to brown spherical structures that resemble mustard seeds.
Unfortunately, there is no curative spray for either disease. Preventative cultural practices can reduce disease incidence and spread. Bacterial wilt infects all members of the Solanaceae family. This includes tomatoes, potatoes, peppers, eggplant, and tomatillo. Southern blight’s host range includes all of those plus beans, peanuts, cucumbers, watermelons, cantaloupes, pumpkins, and sweet potatoes, oh my!
How do you stop these diseases? Remove diseased plants as soon as you see them. For bacterial blight, rotate plantings between members of the Solanaceae family and other vegetables. In the case of southern blight, crop rotation will not work due to the wide host range.
Take care when cultivating the ground and working in the garden that you do not move infected soil to other areas. Soil solarization by covering the ground with clear plastic film for 6 weeks will heat up the soil and kill most disease-causing organisms.
More information on how to do this can be found on the LSU AgCenter website. Testing your soil to make sure the pH is between 6 to 7 and providing good drainage can also lessen disease pressure.
Successful gardening requires persistence! There are tremendous benefits to growing your own vegetables. Growing tomatoes, however, may not be the best choice to reduce stress! I don’t know though; it seems to work for many in my family.
Maybe eating fresh tomatoes counteracts the stress?
Clark Robertson is the assistant county agent for horticulture for Livingston and Tangipahoa parishes. For more information on these or related topics, contact Clark at (225) 686-3020 or visit www.lsuagcenter.com/livingston.
