By Darrell Blackwelder
For the Salisbury Post
SALISBURY — Abnormally high temperatures and relative humidity create a multitude of problems for home gardeners in Rowan County. Insects and diseases are beginning to show in force as the summer continues.
Below are samples of questions that may be of interest.
Q: I have a dogwood with white splotches on the upper side of the leaves. I can take my finger and scrape off the mold. What is it and how can I control it?
A: The problem is powdery mildew. Powdery mildew is a fungus that seems to be worse in hot, humid weather like we’ve experienced over the past few weeks. Control with fungicidal sprays such as Immunex or Funginex if practical. The disease generally does not kill the tree.
Q: My squash plant is inundated with squash bugs. They are literally sucking the sap out of the plant. What can I do to control this pest?
A: Good cultural practices help prevent serious squash bug damage. Proper fertilization of vines produces a vigorous crop better able to withstand insect attack. Removal and destruction of crop debris after harvest eliminates some potential overwintering sites for squash bugs. Adult squash bugs and leaves with egg masses can be handpicked and destroyed. The bugs can also be trapped by placing small boards near the host vines. Squash bugs gather under the boards at night and are easily collected and destroyed the next morning. Use insecticides for larger populations. Be careful not to kill beneficial bees.
Q: My potato vines have little red tomatoes on them. Is this common for potatoes?
A: Potatoes and other crops in the Solanaceous (nightshade family), such as tomatoes, have fruit. The little tomatoes on your potato plant are actually the fruit of the potato plant. These are not edible.
Q: My tomato plants’ lower leaves have turned yellow with black spots and are falling off the plant. What is this and how can I control the problem?
A: The tomato is infested with early blight, a very common fungal disease on tomatoes. If practical, fungicidal sprays such as manzate or zineb will slow the disease. Sulfur and copper sprays may also help, however, costs and time associated with controlling the diseases on a few plants may be prohibitive.
Q: There are beetles on my tomato plants eating the leaves. They are brown and look very similar to lady beetles. What are these insects and how do I control them?
A: These insects are most likely bean beetles. They feed on a variety of vegetable crops, including tomatoes. Hand-pick the beetles if practical or use Sevin dust or liquid to control infested or large population plants.
Darrell Blackwelder is the County Extension Director with horticulture responsibilities with the North Carolina Cooperative Extension Service in Rowan County. Learn more about Cooperative Extension events and activities by calling 704-216-8970 or online at www.rowanextension.com