Watch Out For Tomato Diseases!

By HENRY HARRISON LSU AGCENTER,

There are many disease problems that will plague tomatoes grown in our parish.

Some of the major problems are Fusarium wilt, early blight, buckeye rot, blossom-end rot and spotted wilt viruses, just to name a few. Blossom-end rot is found on the blossom end of the fruit and is dry and leathery. It is caused by water changes or moisture fluctuation. The rot will likely develop during dry periods after wet periods. Low levels of calcium in the soil can also cause blossom-end rot.

Over-fertilizing with nitrogen can also induce the rot problem. A soil test is necessary to determine if nitrogen and calcium are needed. Blossom-end rot can be controlled by maintaining an even supply of soil moisture and applying calcium, if needed. Bacterial wilt is sudden; plants will not show yellowing of leaves. The stem of the plant in the center, or pith, becomes water-soaked, later turns brown and sometimes becomes hollow. To test for bacterial wilt, cut acrossthe stem of infected plants, squeeze slightly and place in a pint jar of water. Support the stem to the jar rim with a paper clip, and if bacterial is present, you will see a long white stream of mycelium oozing from the stem.

Fusarium wilt is the most common and destructive soil-borne disease in our parish. The disease is most severe during warm weather. The fungus enters the plant through the roots and develops inside the stem. The leaves show a progressive yellowing and wilting, starting at the bottom. The fungus/bacteria may linger in the soil anywhere from 10-15 years. Two weeks may pass between first symptoms of Fusarium wilt and plant death, and if an affected plant's stem is cut near the soil-line, a brownish discoloration can be seen in the inner tissues of the plant. The best control measure of Fusarium wilt is to have used disease-resistant plants. Now, you should keep in mind that resistant does not mean immunity. Under stressful conditions or in heavily infested soils, these resistant varieties may also develop the disease.

The key to controlling diseases is prevention. Using a regular spray program with fungicide will do the job. Remember, I said regular spraying, following the directions from the label.  Some useful fungicides in controlling tomato diseases are Maneb, Bravo, Ridomil and Benomyl. The fungicides can be mixed with most of the common tomato insecticides (Malathion, Sevin). You may want to alternate two of the fungicides to increase the range of protection and prevent the build-up of resistant fungi.

School Gardens

With the excitement of school coming to a close, there is a group of students involved in a project that will continue throughout the summer after school officially ends - school vegetable gardens. School vegetable gardens allow students the hands-on experiences on how to grow and produce a crop. During the summer, the LSU AgCenter, with the Master Gardeners, will provide the necessary upkeep to these gardens until school reopens. When the participating students return they can see and understand that growing a garden can be a year round activity. Thanks to the support from our school systems, gardening is an integral part of learning. The participating schools are: Thomas, Franklinton, Wesley Ray and Central Elementary. The LSU AgCenter would like to thank the superintendents and teachers for providing us with the opportunity to work with your students on learning where our food comes from. Go visit the schools and let us know what you think about our gardening efforts. You will be amazed at what our children/students have accomplished.

Also, the Master Gardeners have a small community vegetable garden at the public library in Franklinton. Go pick some strawberries and squash, cucumbers and tomatoes.