Denny's Soapbox

As the larvae hatch, they drop out the bottoms of the bags on a strand of silk. If there is a breeze, the tiny larvae are picked up and blown to nearby plants (we call this ballooning). While most of the larvae don’t blow any further than the plant on which their parents resided, some can be blown quite a distance (several hundred feet). This is why you can get a bagworm infestation on plants that are not near other infested plants!

Bagworms do their worst damage by defoliating conifers, especially junipers, arborvitae, spruces and even white pine. Remember that conifers can’t replace eaten foliage once they have put out their current year’s growth. I’ve seen entire tops of trees, one side or even whole trees killed in one season by bagworm defoliation.

Remember that bagworms feed on a pretty wide range of deciduous plants, but their defoliation doesn’t kill these plants. My personal belief is that these are usually missed, but they serve as sources of reinfestation in subsequent years.

When bagworm bags are less than 3/8 inch in length, even the biobased insecticide, Bt will kill them. Of course, the pyrethroid will kill them too as will the one neonic, acetimiprid (TriStar). Unfortunately, we are still looking for something that can be applied as a basal drench to protect all conifers without having to resort to tall tree sprays. Dave Shetlar – O.S.U. Entomologist

Lace Bugs. Overwintered HAWTHORN LACE BUG (Corythucha cydoniae) and OAK LACE BUG (C. arcuata) adults were observed laying eggs on the leaves of their namesake hosts in southwest Ohio. Like most lace bugs, hawthorn lace bugs live on the underside of leaves. They have a cosmopolitan palate and may be found on several species in the Rosaceae family including cotoneaster and Amelanchier as well as hawthorn. Oak lace bugs focus their attention on their namesake host, but they are particularly fond of oaks in the white oak group. These lace bugs are unusual in that they live on the upper leaf surface.

Lace bugs use their piercing/sucking mouth parts to suck juices from their host plants. Their feeding produces tiny yellow or whitish leaf spots (stippling) that may coalesce to produce large, yellow-to-copper colored areas on leaves, and early leaf drop. Lace bugs also deposit unsightly hard, black, varnish-like tar-spots of excrement onto the leaf surface as they feed. The bugs have multiple generations per season, and their damage builds with each succeeding crop of bugs. It is important to closely monitor and control lace bugs early in the season to avoid the collective damage produced by successive generations.

Red Thread. This relatively superficial disease has become active in many parts of the state, especially on ryegrass and fine fescue. Red thread can be found on all cool season grasses depending on the situation. However, it is most common on perennial rye, fine fescue, and to some degree on Kentucky bluegrass. The disease can be identified form the pinkish to reddish colored patches. The color and texture can vary considerably. Often, the patches will appear to give a pink color to the leaf blades or to resemble pinkish globs of bubble gum or cotton candy on the leaf blades.

This disease is strictly a superficial problem and one that will not kill the turf. Under serious conditions, it can reduce the overall appearance of a lawn. Make sure the lawn has adequate nitrogen and phosphorus to manage a healthy robust stand of turf. A deficiency of either significantly increases disease severity. Fungicide programs can be considered in unusual situations where the disease needs to be prevented.