Carpenter bees move right in and take over a wooden deck


May 16, 1999

Q. Help! Some large black and yellow bees are chasing me off my deck. I think they are making small holes in my wood siding as well. Do they sting, and will they ruin my siding?

A. You've got carpenter bees moving in. Single females tunnel into weathered, unpainted or untreated wood to lay their eggs. You might have noticed little piles of yellow sawdust below the holes.

The females will sting only if trapped. The males guarding the tunnels may appear menacing but they have no stinger.

You can spray an aerosol insecticide or puff a powdered insecticide into the holes, wait a week and then caulk and paint the damaged siding. If the holes are not filled, the bees may return each year and extend the tunnels.

Q. I just bought and transplanted some pepper and tomato plants. I bought them because they were blooming already in their container. When I got them home, I realized that they were infested with small, white flying insects. What should I do?

A. First, it's not a good thing that the plants are blooming already. Remove all the open flowers now. Premature fruiting signals to your plant that its job is done. That can greatly reduce your yield.

Flowers on tomato and pepper plants are a sign that the plant has overgrown its container and may be stressed. The little white insects you see are whiteflies, which suck plant sap. You can control them by spraying the foliage thoroughly with insecticidal soap or horticultural oil.

Q. I just moved into a townhouse with a sunny deck and want to grow container vegetables and herbs. I want to know how to create a good soil for my potted plants this summer.

A. Try a 1-to-1 mixture of aged compost and good topsoil or a 1-to-1-to-1 mix of aged compost, good topsoil and either sharp sand or a soilless growing medium. This will produce a loose, porous mix that will allow good root growth, and retain moisture and nutrients. Be prepared to water your plants daily and fertilize them every two weeks.

Q. Last week I noticed many small black insects flying around my English hollies. Is this a pest I should be concerned about?

A. Your visitors are probably holly leafminer adults. The immatures are maggots that tunnel and feed in leaves in summer, producing yellow mines -- narrow, curved tunnels between the upper and lower leaf surface.

Remove and discard affected leaves to eliminate over-wintering larvae. Naturally occurring parasites also will help to keep the leafminer population in check. Consider applying a systemic insecticide if a large number of leaves are mined.


1. Spot-treat broadleaf weeds in the lawn with a liquid herbicide. Avoid spraying the entire lawn or using "weed and feed" combinations.

2. Hand-thin fruits on peach, apple and pear trees so they are spaced 5 to 6 inches apart.

3. Make sure mulch is at least 4 inches from tree trunks and the bases of shrubs.

Garden tips are provided by the Home and Garden Information Center of the Cooperative Extension Service of the University of Maryland. For additional information on these questions, or if you have questions of your own, call the center's hot line at 800-342-2507, or visit its Web site at www.agnr.umd .edu/users/hgic.

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