Friday, January 16, 2009
Managing pests on house plants
John Arbogast
Landscape consultant John Arbogast answers your questions every Thursday. Send questions about your lawn, garden, plants, or insects to:
Dear John
5102 Greenfield St. SW
Roanoke, Va. 24018
Or send an e-mail. Answers will be given only in this column. Please don't send pictures or samples.
Recent columns
Q: You’ve written before about insects on indoor plants when houseplants are kept on cold windowsills or under lights in chilly basements. I have had problems with pests on some of my indoor plants and am wondering what I can do to save the plants in my cold house.
A: I had to ask Eric Day, Extension entomologist at Virginia Tech, for answers from his current Virginia Tech Pest Management Guide.
Your options are limited when it’s too cold to take infested plants outside to spray. Few pesticides are safe or legal to use indoors.
If just a few indoor plants are lightly infested with insects or mites, isolate the healthy plants from the infested area. If plants are severely infested, they might need to be tossed out.
Washing the lightly infested plant with warm water and small amount of insecticidal soap is effective in removing aphids, mealybugs, mites, thrips, scale insects and whiteflies. Lightly spray the leaves and stems, particularly where leaves and branches join the stems, with a gentle spray from a faucet or sink hose.
The bases of the stems and the crowns of plants are difficult to wash, but often harbor the pests.
Wiping or cleaning foliage and stems with a soft brush or cloth dampened with detergent or rubbing alcohol will remove most of the bugs.
A cotton swab dipped in rubbing alcohol or fine tweezers is a convenient way to remove mealybugs, scale insects and aphids. Be sure to check cracks and crevices where petioles and branches join the stems.
If plants are severely infested, wash them and prune the most severely injured foliage and stems to permit regrowth and recovery.
If entire plants are damaged, it is best to destroy them before contaminating other plants or planting areas.
Q: I core aerated and overseeded most of my bluegrass/fescue lawn in Virginia early last fall and about half of the lawn looked pretty good until winter. I kept up with the autumn leaves and removed them before they could smother the grass. With the wet winter we’ve had and the cold temperatures that have kept the soil wet, parts of my lawn look bad with only thin grass but a lot of bare spots showing. Will it look better in the spring?
A: For now, wait and see. You can also take soil tests when the ground is not frozen to see if lime or agricultural sulfur needs to bring the soil pH to the slightly acid range of 6.2 to 6.5. Recommendations come with soil test results, but materials applied to adjust soil pH work very slowly.
Try to keep yard equipment, frequent feet, wheels or paws off the same parts of the grass.
Does shade or poor drainage affect parts of your lawn? If so, take corrective actions as appropriate.
Have your mower serviced now. Set mower blade height to 3 inches.
