Lack of proper weed control probably limits production in home gardens more than any other production practice. Weeds compete with vegetable plants for water, nutrients and sunlight and must be controlled if garden vegetables are to grow and produce well. Weeds also serve as a refuge for insects, as well as alternate hosts for diseases. Use mulches to control weeds and to retain moisture. Both black plastic and various organic mulches may be used.
Most vegetables are susceptible to one or more diseases. By following good cultural practices and taking preventive measures, your chances of garden failure due to disease problems can be reduced. Tomato and pepper are susceptible to tobacco mosaic virus. Tobacco mosaic virus is carried in tobacco products and is easily transmitted to susceptible vegetables on workers’ hands. Workers should wash their hands thoroughly in soap and water after handling tobacco products and before they work with tobacco mosaic susceptible plants.
Watering can influence the development and severity of many foliage diseases. Wet foliage is favorable for the development of most diseases. To reduce infections, apply irrigation water to the soil rather than the foliage. If water must be applied to the foliage, it should be done in late morning or mid-afternoon to allow the foliage to dry before evening. Excess soil moisture can damage vegetable roots, as well as promote root diseases caused by certain fungi. It is best to work in the garden when the foliage is dry to reduce disease spread. Bacterial diseases of tomatoes, beans and other crops are readily spread on hands and clothing of workers when the foliage is wet. Maintaining uniform soil moisture can reduce problems such as blossom end rot of peppers and tomatoes.
Fungicides can be a great help in preventing diseases when properly applied to the plant foliage. Since fungicides are preventive, they should be applied before the disease occurs, or as soon as the first symptoms of disease appear. A spray schedule should be followed that maintains a protective fungicide layer on the foliage and fruit during favorable infection periods. Always read the label of all products used.
Crop rotation will help prevent the build up of disease-causing organisms in the soil. Some disease-causing organisms affect one vegetable or group of vegetables, but may not affect another. Several vegetables of the same family such as squash, cucumbers and cantaloupes may be affected by the same disease. Therefore, it is not a good practice to grow plants of the same family in rotation.
Sanitation is important in controlling vegetable diseases. Many disease-causing organisms survive the winter in plant debris, cull fruit or plant stubble left in the garden. Any practice that will eliminate these overwintering sites for fungi, bacteria, viruses and nematodes will reduce the occurrence of disease problems the following year. Removal or plowing-under of crop stubble and trash helps destroy overwintering populations of disease organisms.
Air movement through the garden is also important to help dry the foliage, thus reducing the chances of fungal and bacterial infections. Proper plant spacing is very important in vegetable crops. Humid or wet conditions occur if plants are crowded and unable to dry quickly. Blossom blight of okra and squash and fruit rot of strawberries are encouraged by dense foliage. Also, pesticides will not penetrate through this canopy of foliage. Most garden vegetables require full sunlight for maximum production. Sunlight also hastens drying of foliage.
Insect control can reduce the spread of diseases in the garden. Cucumber beetles can transmit bacterial wilt, flea beetles are a source of Stewart’s wilt of corn and aphids transmit numerous virus diseases. Insects also cause injuries that serve as entry sites for disease organisms. Vegetables should be checked regularly for insects, with insecticides applied carefully, if needed. Be aware there are some insects that are considered beneficial and should be identified and encouraged. Beware and take care not to harm beneficial honeybees. They are your friend.
For more information, contact the UT-TSU Extension Office in Wilson County at 615-444-9584. You can also find us on Facebook or visit extension.tennessee.edu/wilson.
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Through its mission of research, teaching and extension, the University of Tennessee Institute of Agriculture touches lives and provides Real. Life. Solutions. ag.tennessee.edu. Ruth Correll, UT Extension-TSU Cooperative Extension agent in Wilson County, may be reached at 615-444-9584 or [email protected]