Friday, November 13, 1992 - Page updated at 12:00 AM

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Practical Gardener

Use Cryptocidal Soap To Kill Liverworts

WSU / King County Cooperative Extension

Q. What can I use to kill liverworts on bare ground?

A. Safer's cryptocidal soap will destroy moss, algae and liverworts. Apply it according to label directions.

Q. I've been told that I should treat my lawn for chinch bugs, billbugs and sod webworms. Should I?

A. West of the Cascades these insects really fall into the category of non-pests. Sod webworms or lawn moths do exist in Western Washington, but they seem only to be pestiferous on cranberries. Eastern Washington lawn owners may find their lawns damaged by this critter chewing on the grass blades, but just because moths are noticed flying about a turf area, it doesn't necessarily follow that they are the cause of problems occurring in the lawn. Lawn problems tend mostly to be cultural or environmental in nature.

Lawn damage is often blamed on chinch bugs, small black insects about 3/16th inch long with white markings on their wing covers. Young ones are likely to be reddish. Although the chinch bug may be a significant pest in the Midwest, the East Coast and perhaps Eastern Washington, it only rarely causes injury to lawns in Western Washington. In fact, most of the damage attributed to it is caused by drought, heavy thatch accumulation and poor drainage.

Before using an insecticide to control it, check to see if the pest is really present. Put a piece of damaged turf in a clear plastic bag (a piece with both brown and green blades should be chosen), and if they're present, they'll be all over the sides of the bag in no time.

Billbugs are long-snouted black weevils about 3/8 inch long whose larvae feed on grass roots. They're little white worms, about a quarter-inch long, with black heads. This beast is strictly a pest east of the Cascades and has not been collected on the west side.

The only significant insect pest of grass in maritime Washington is the European crane fly, whose damage appears in late winter/early spring. If control is necessary, it can be carried out then.

Q. I've seen ads for a scented geranium that's supposed to repel mosquitoes. Is this for real?

A. Like most things that seem too good to be true, this is. A number of plants produce a compound, citronella, which is reputed to repel insects, but even if the geranium in question does contain citronella, you'd need one heck of a lot of geraniums for them to do any good. There is no scientific evidence that you'll get anything more for your money than a pleasantly scented geranium.

Gardening runs Friday in Scene and Sunday in Home/Real Estate. It is prepared by George Pinyuh and Holly Kennell, Washington State University/King County Cooperative Extension agents, Mary Robson, Master Gardener program assistant, and volunteer Master Gardeners.

Copyright (c) 1992 Seattle Times Company, All Rights Reserved.


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