Wheat aphids (both bird cherry-oat and greenbugs) continue to cause concern in the central part of Kansas. However, natural enemies, both lady beetles and parasitoid wasps, are also present and growing conditions are good.

So, treating for aphids is always a possibility, but has not often been justified. It takes a pretty healthy population of aphids (30 to 50/tiller) with no lady beetles or mummies (indicating the wasp is active) and less than ideal growing conditions before an insecticide application to prevent damage from aphid feeding is justified.

Both species of aphid can transmit a virus that causes barley yellow dwarf, but a foliar insecticide application now will not guarantee the disease has not, nor will be, transmitted to the plants. Get out and walk a few wheat fields and see what's happening at ground level and in the plant canopy.

Sharp mower blades

Lawn-mowing season is here. Remember that dull blades give the lawn a whitish cast. A dull blade does not cut cleanly, but rather shreds the ends of the leaf blades. The shredded ends dry out, giving the lawn that whitish look.

A sharp mower blade is even more important when the turf starts putting up seed heads in a month or so. The seed head stems are much tougher than the grass blades and more likely to shred. Under normal use, mower blades should be sharpened about every 10 hours of use.

Bagworms

Timing is critical in many things, including controlling bagworms. Though handpicking is effective through much of the year, often it is impractical because of the sheer number of bagworms. But if you only see a few bags, now would be a good time to pick them off and destroy them, place in the Dumpster or squash the bags with the heel of your shoe.

New bagworms will likely hatch and leave the mother's bag in May, but spraying is not usually recommended until later in June. Spraying now will be ineffective because they are too well protected inside their mother's bag.

Closer to hatch, watch for an article on when and what to spray.

Ash/lilac borer

If you have had problems with canes or stems of lilac and privet suddenly wilting, or ash trees that show borer holes in the trunk and larger branches, the ash/lilac borer may be to blame. This insect causes the base of infested lilac stems to swell and the bark to separate from the wood. A fine, sawdust-like material is present around holes in the canes. Ash and mountain ash also are affected. The borer attacks the trunk, which may cause bark to swell and crack if there are repeated infestations.

Ash/lilac borers overwinter as larvae in infested trees and shrubs. Moths generally begin to emerge in mid- to late April. Emergence peaks in May, dwindles by mid- to late June and ends by the first week of July. However, this year the moths will be earlier (see below). The moth has clear wings and resembles a wasp. There is one generation per year.

The first spray for ash/lilac borer should be applied when the Vanhoutte spirea is in full to late bloom, probably by about April 12 to 20 this year. Apply a second spray four weeks after the first. Thoroughly treat the trunk and larger limbs of ash or the lower portion of the stems of lilac or privet. Heavily infested ash should be cut and burned during the fall and winter.

Infested stems of lilac or privet should be removed as well. Bifenthrin or permethrin (Hi-Yield Garden, Pet, and Livestock Insect Control and 38 Plus Turf, Termite and Ornamental Insect Control) are examples of labeled chemical products for control. Though there are a number of homeowner products that contain one or the other of these two active ingredients, the permethrin products listed above are the only ones I've found that specifically lists the ash/lilac borer on the label with directions for control.

For more information or assistance on this or other topics, please call the Extension office at 272-3670, located at 501 S. Ninth St.