Insects

Ash tree borers: I have a very old ash tree that has been diagnosed with borers. What can I do to save the tree?

Answer: Borers are opportunistic pests. They will attack a tree, no matter its age, that is under a great deal of stress. The best defense against this pest problem is to keep the plant as healthy and stress free as possible. Stress can be brought on by a number of factors including weather, poor pruning, trunk injury or old age. In some cases, the tree may be so stressed the survival is unlikely.

The key to borer control is prevention. The first line of defense is to keep the plant healthy. If that fails, then the tree can be treated chemically. Borer control normally consists of three applications of an insecticide. The first application is made in mid-May with two subsequent applications at three week intervals. Applications should be made to the entire trunk of the tree, including the soil around the base, up to where the main branches join the trunk. This treatment keeps borers from entering the tree and should be repeated each year, as necessary.

Bug zappers to control insects: How effective are bug zappers at controlling insects?

Answer: Bug zappers work by emitting light to attract insects. Many people think they are highly effective because they make a noise signaling another insect has been killed. However, they are probably not destroying bugs in numbers great enough to make much difference. If you decide to use a bug zapper, locate the device away from the area to be protected. Because bugs will be attracted, do not place them near a patio or area that you want to be bug free. Remember that there are many beneficial bugs in the garden. Bug lights do not know the difference between a good bug and a bad bug. They all get zapped.

People often ask about using citronella candles to control pests. It is true that they do work, but only in the five-foot area where the smoke is concentrated. Beyond that distance, the benefit is lost.

To enjoy a pest-free patio, try this trick. Place several oscillating fans around the area to keep the pests at bay. Insects such as gnats and mosquitoes are worse on calm, still nights.

Termite control products: I have seen advertisements for wood mulch products that control termites. Do these products work?

Answer: Unfortunately, this “too good to be true” product will not provide a great enough termite control product to provide protection. The wood mulch products on the market that are advertised for termite control contain disodium octaborate tetrahydrate or borate. Borate products can be used as a supplement treatment against termites. However, they are not a control for termites and would provide little benefit when used as mulch. As the mulch heats up and dries out, it becomes unattractive to termites. Termites prefer the soil layer under the mulch that remains cool and moist. Termites normally enter the home through buried wood or dead roots around the home. There is often a concern that the use of wood mulch around the home will cause a termite infestation. This should not be a major concern as long as the mulch is applied to the soil surface and never buried.

K-State Research and Extension Master Gardener Logo
Have questions? The Hotline is staffed by trained EMG volunteers and Extension staff who will assist you with questions.

Phone: (913) 715-7050

Email:
garden.help@jocogov.org