Greg Bowman

I would like to continue our topic from last week on vegetable garden disease management. Vegetable gardening is the top hobby for many citizens in the area. I do not take the word hobby lightly since vegetable gardening takes dedication and means a lot of work for the gardener. I also realize that many people use the yield as the main source of feeding their family. Vegetable gardening can be a great outdoor activity that can be very rewarding when you can provide fresh produce for family and friends.

Managing for potential disease issues in the garden is very important in keeping the area productive. I will again be sharing information from a UGA publication revised by Elizabeth Little, UGA Home Garden/Small Farm Plant Pathologist.

As a quick review, fungi, bacteria, nematodes and viruses are the four primary organisms that cause plant diseases. These organisms are sometimes called pathogens or plant parasites. You normally will have issues from fungi or bacteria when temperatures are warm with more moisture. Viral diseases are more common in summer when insects that carry these diseases are more active. Finally, nematodes normally are more of a problem when temperatures are warm, but they can cause root issues all year.

Last week, we discussed importance of site selection, crop rotation and variety selection as a few of the topic in regards to disease management. Today, we will cover more topics in the area of disease management in vegetable gardening.

For starters, knowing when and how to water vegetables is important. Elizabeth Little states that constantly wet soils contribute to soil-borne diseases such as seed decay, damping-off and root/crown rot. In addition, water on foliage contributes to foliar disease issues. You want to encourage a healthy root system in vegetables so water deeply and only when needed. Water deeply with one inch equivalent of water when needed and normally no more than once per week while keeping tabs on rainfall. More water is needed in hot and dry weather.

Drip irrigation is more efficient as compared to sprinkler irrigation. If you choose to irrigate with a sprinkler, you need to do so in the early morning hours so the plant foliage will dry quickly. You actually can start disease in your garden by using a sprinkler in the afternoon hours. Remember, the foliage needs to stay dry and if you soak the foliage in the afternoon, you have extended the amount of time the foliage is wet. Thus, you could have added the last key ingredient for disease establishment.

Mulch can be beneficial, too. Mulch can help conserve soil moisture which can also help with blossom end rot problems in items such as tomatoes and peppers. Blossom end rot is a calcium deficiency and keeping soil moisture uniform can cut down on the incidence of this issue. Mulch can also help with disease management. Some plant disease pathogens survive in the winter in soil debris. Mulch layers of straw, bark, leaves, shredded paper or plastic will reduce the amount of soil splashing on plants and will keep the vegetables from making contact with the bare soil. This can cut reduce the changes of soil born diseases. Mulch will also help reduce weed populations and will add organic matter to the garden soil as the material breaks down.

Do not forget about good vegetable garden sanitation. The removal of potentially diseased plant material is a good way to reduce the survival of disease causing organisms and reduce future disease outbreaks. It is a good idea after harvest, to remove these plants and their residue. Uprooting the entire plant of potentially disease item is good. Remove and destroy the diseased plant. Also note that leaf spot outbreaks can also be reduced if early infected leaves are removed and destroyed in regards to sanitation.

Finally, in regards to vegetable varieties, choosing varieties with known resistant qualities may be the best way to manage for disease. Remember that resistance is a relative term. Some varieties can be total immunity to some diseases while others may be partially resistant depending on the variety and the disease.

For more information, contact UGA Extension- Gordon County at 706-629-8685 or email gbowman@uga.edu.