-
- Articles
Index : Plant Problems - Cultural
-
-
- 14. Summer Garden Problems - Top
- Summer vegetable gardens in the desert tend to suffer from a number of problems, and this year is
no exceptions! Hot weather, a large insect population, and higher than normal incidence of
disease have combined to spoil many home gardens.
Heavier than normal rains from El Nino produced an abundant crop of wildflowers and grasses.
This abundant food source, combined with mild winter weather created a heavier than normal
crop of insects. Among them were common garden pests such as aphids and leafhoppers. These
small sucking insects have made a feast on tomatoes, pepper, squash, eggplant and other summer vegetables. Their sucking out of plant fluids usually results in a rather harmless and temporary curling of new leaves. However, these insects transport a much more serious condition known as "curly top".
Curly top is a virus disease. It causes a number of types of vegetables to develop curling, thick
leaves. Although the symptoms of curly top resembles a wilt from lack of moisture, watering will not correct the problem. The virus is most common on tomatoes, but has a wide host range of
vegetables. Plants infected when mature usually are not killed by the virus, but are stunted and
the fruit production is greatly reduced.
There is no control for curly top. The virus is spread from diseased plants to healthy ones by
insects such as thrips, aphids and leafhoppers. Because the populations of these insects are so
large, and continuous, no amount of spraying will stop there feeding. There are no vegetable
varieties resistant to curly top virus. The best way to reduce the spread of curly top is to remove infected plants. Any tomatoes or other vegetable plants having a wilted appearance, should first be checked for moisture stress.
Plants should be watered thoroughly and given a day or two to recover. If they don't, but continue to look curled and wilted without dying, it's probably curly top. Removing infected plants as soon as possible will help prevent the disease from spreading. A plague of locust, commonly known as grasshoppers, has also been damaging garden plants.
The grasshoppers have been abundant this year, again due to all the grasses and weeds produced
by the El Nino rains. As the grasses and weeds turned brown this summer, grasshoppers have moved into gardens looking for food. Adult grasshoppers are next to impossible to control with sprays, regardless of how potent the material. The only effective way to prevent grasshopper damage is to provide a physical barrier to keep them off garden plants. Frost blanket materials, such as remay, and shade cloth coverings let sun and rain in but keep bugs out, especially big ones like grasshoppers! These coverings should be secured to the ground to prevent grasshoppers from inadvertently crawling under.
Mesh coverings, whether frost blankets or shade cloth, are also helpful in protecting garden plants from our intense Arizona sun. Strong sunlight can severely stress even summer vegetables. Shading keeps plants healthier and extends the production of flowers and fruit. A 30 % shade cloth is ideal, but any amount of shade will help. Garden centers sell shade cloth and frost blankets. You can also use materials such as old window screens, reed fencing, or burlap for shading plants. Locating the summer garden where it will receive filtered shade from a tree is also a good option.
Summer gardening problems can be discouraging. However, keep in mind that autumn in Tucson provides some of the best gardening conditions anywhere in the country. So forget those summer
gardening woes, sharpen up the pencil, and make plans for a bountiful fall garden!
--------------------------------------------------------------------------------
Written by John Begeman, College of Agriculture, the University of Arizona, 520-626-5161.
Material originally appeared in Arizona Daily Star gardening column, on August 9, 1998
- Updated: August 9, 1998
-
-
[e-Mail me
the Articles] - [Search
the Articles]
-
|
