Extension News

Ask the ISU Extension Garden Experts: Beetles, Deer Damage and African Violets

Note to media editors: Got gardening questions? Call the Hortline at (515) 294-3108, Monday-Friday from 10 a.m. to noon and 1 to 4:30 p.m., or e-mail us at hortline@iastate.edu. For more gardening information, visit us at Yard and Garden Online, http://www.yardandgarden.extension.iastate.edu

10/8/2009

How do I keep multicolored Asian lady beetles out of my house?

The multicolored Asian lady beetle is one-third inch in length, dome-shaped, yellowish-orange to red with variable black spots on the back. Deep orange is the most common color. The 19 black spots may be faint or missing. There is a black “W” shaped mark on the thorax.

Asian lady beetles follow their instinctive behavior and fly to sunny, exposed surfaces when preparing to hibernate through the winter. The time of beetle flight varies but is usually from mid-September through October (depending on weather). Light colored buildings and walls in full sun appear to attract the most beetles.

Sealing exterior gaps and cracks around windows, doors, eaves, roofs, siding and other points of access before the beetles appear can prevent unwanted entry. Experience suggests, however, that comprehensive pest proofing is time-consuming, often impractical, and usually not 100 percent effective. For large infestations with intolerable numbers of beetles, spraying pyrethroid insecticides such as permethrin or esfenvalerate to the outside of buildings when the beetles appear may help prevent pest entry. Homeowner insecticides other than pyrethroids usually do not provide satisfactory prevention.

The most practical control for beetles already inside is to vacuum or sweep them up and discard. Indoor sprays are of very limited benefit. Interior light traps are available.

How can I prevent deer from rubbing off the bark on my small trees in the yard?

In fall, bucks rub their antlers on trees to remove the dried velvet from their antlers and to mark their territory. This rubbing removes the thin layer of bark on small trees and can seriously damage or destroy them. Trunk damage typically occurs one and a half to three and a half feet above the ground.

Damage caused by bucks rubbing their antlers on small trees can be prevented by driving three wooden stakes or fence posts around each tree. Space the stakes or posts about 18 inches apart.

My African violets aren’t blooming well. Why?

The African violets may not be receiving adequate light. The proper amount of light is essential for good bloom. Generally, windows with north or east exposures are best for African violets. However, if these exposures are not possible, they also perform well under fluorescent lights. Suspend fluorescent lights eight to 12 inches above the plants. The lights should be lit for 12 to 15 hours per day.

Excessive fertilization also could be responsible for the poor bloom. African violets need to be fertilized to promote bloom. However, excessive fertilization leads to vigorous vegetative growth and poor flowering. Using a complete, water soluble fertilizer, apply a dilute fertilizer solution once every two weeks in spring, summer and fall. Fertilization usually isn’t necessary during the winter months.

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Contacts :

Richard Jauron, Horticulture, (515) 294-1871, rjauron@iastate.edu

Del Marks, Extension Communications and External Relations, (515) 294-9807, delmarks@iastate.edu