How to Stop Wireworms From Ruining Your Lawn

Published
04/21/2010 by

An infestation of wireworms will kill your grass and can remain a chronic lawn care problem that will last for years.  Wireworms are the larvae of a group of beetles commonly called click beetles.  Larvae are the young insects that are markedly different than how they look as adult insects: caterpillars and fly maggots are good examples.

The adults are called click beetles because they make a clicking sound as they flip from their backs to their feet.  The worms are a major pest of potato production in Canada and can easily ravage potato crops. There are more than 900 valid species of wireworms found throughout North America and while most are harmless to turf grasses, some species are serious pests.

Wireworm Life Cycle

The female click beetle will lay her eggs in the soil in May and June. Her larvae - or wireworms - develop in the soil over several years. Depending on the species, the cycle can be between three and six years. Most of this lifecycle is spent as larvae feeding on your lawns root system.  They thrive in poorly drained, moist, compacted soil.  

Wireworm larvae are yellow or brown worms that can range in length from 1 to 2.5 centimeters. They are distinguished from other immature insects by their tough wire-like appearance in contrast to most soft-bodied immature stages of other insects such as maggots. The larvae have six tiny legs close to the head.

Lawn Damage

Wireworms will live in your lawns' soil and feed off of the roots of your grass.  The damage inflicted on your lawn by wireworms can be easily mistaken as drought because of the root damage that occurs to your grass.  

They tend to move up and down in your yards soil depending on the weather conditions.  Wireworms pass easily through your soil due to their shape and their tendancy to follow pre-existing burrows.

How to Get Rid of Wireworms

May and June are the best time of year to get rid of this pest - when the click beetles lay their eggs.  Make sure that your grass is adequately fertilized with a balanced soil ph.  Aerating is also very important because the beetles like to lay their eggs in compacted soil.

Spread a mixture of diatomaceous earth and soap powder at a rate of 6 to 9 kg per 100 m2, or a tablespoonful of pyrethrum dissolved in 4 L of water, up to four times a year. A high-potassium fertilizer, such as seaweed, may also be applied in fall to help the lawn resist the cold.  This treatment is also recommended to control grubs.

Finally, if you do have a lawn problem then you may find it worth your while to call in a professional lawn care service.  They likely won't charge you for an initial visit and they'll correctly diagnose the cause. They also have the equipment and the know how to solve the problem safely if you don't want to tackle the problem yourself.