Issue: April 26, 2003

Beet leafhopper/curly top virus outlook

Do you have a "prediction" as to how the leafhopper population is this year regarding curly top virus in tomatoes? I have several tomato plants under water shelters and will be planting several more in the next week or so. George D. Albuquerque

Extension Service agents around New Mexico report that there is quite a bit of mustard weed. These weeds serve as winter host to the virus and spring host to the beet leafhopper. They germinate in the fall and become infected with the curly top virus, then host the virus through the winter without being injured themselves. They also serve as shelter and food for the beet leafhopper that carries the virus from plant to plant. Therefore, the potential for curly top virus is fairly high in New Mexico this spring. To minimize the problem, eliminate the mustard weeds. This will reduce the possibility of problems. You may also wish to wrap the tomato cages with cheesecloth or white row-cover fabric to exclude the leafhopper. Light and air can penetrate the covering, so the tomatoes grow well under the slight shade. You can unwrap the covering to harvest tomatoes and re-wrap it to continue the protection. If the tomatoes outgrow the cages and covering, then remove the covering. If the plants get the virus, you can still harvest any tomatoes that have formed. It is important to remember that the curly top virus does not infect plants directly from the soil or from compost. For that reason, it is safe to compost curly top infected tomato plants and to plant tomatoes near areas of the garden that had curly top problems in previous years. Spraying insecticides to kill the leafhoppers provides little benefit. The insecticide often excites the insects causing them to spread the disease before dying. Weed management and preventing insect access to the plants are the best ways to reduce the potential for curly top virus problems.

Indoor lemon tree

I am very interested in growing a lemon tree. I understand that a lemon tree will freeze in New Mexico, so is it possible for me to grow a lemon tree indoors?

It is possible to grow lemons in New Mexico, but it is difficult. You are correct that the tree will freeze in most areas of New Mexico in the winter but will do well outdoors in the summer. Some nurseries sell dwarf varieties that may be grown as container plants. These container-suitable varieties are the ones to try. As the tree becomes larger and the container becomes heavier, it may be wise to get a wheeled "dolly" to place under the container so you can easily move it indoors in the winter and outdoors in the summer. While it is possible to keep the tree in a garage during the winter in many parts of New Mexico, a sunny location is better. For proper color development of citrus (including lemons), cool conditions are necessary. For that reason, its winter location should be cool. Bright light is also important during the winter. During the summer, a partly shady location is recommended. Protection from hot, drying winds will also help.

Send gardening questions to Southwest Yard and Garden, Attn: Dr. Marisa Thompson at desertblooms@nmsu.edu or at https://www.facebook.com/DesertBloomsNM/. Please include your county Extension Agent (aces.nmsu.edu/county) and your county of residence with your question!

For more gardening information, visit the NMSU Extension Horticulture page: desertblooms@nmsu.edu.

Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, office: 505-865-7340, ext. 113.