Billbugs are often known as a great problem for causing damage to both lawns and plants. It is when Billbugs are in their larval stage that they feed on the roots of the sod and create the greatest damage, though adult Billbugs can also feed on roots of turf and plants. The adult Billbugs can often be seen walking across lawns and paths up tree trunks, and amongst plant foliage. Billbugs are a part of the Weevil family, often referred to Snout Beetles.
Billbug Life Cycle
There are two different types of Billbugs, there is the Bluegrass Billbug which will hide throughout the garden in covered areas in the colder seasons. It will lay it's eggs between May and July, the hatched larva will the begin feeding on lawn roots almost immediately with the greatest damage occurring over the next few months as they continue to fatten up. They will then burrow deep into the soil to pupate and transform into adult Billbugs a few weeks later. As Winter approaches the adult Billbugs will find shelter to over-winter.
The Denver Billbug is usually more common in most States, and can either over-winter as adult Billbugs, or remain in their larval stage for over-wintering. As the larva emerge in the Spring, they will begin feeding again for a short period of time before pupating and transformation occurs.
Billbug control can be both easy and difficult depending on where the main infestations occur. For lawn infestations a grub killing insecticide can be applied to the sod and watered into the soil. Noting that any heavily thatched lawns will have severely diminished results with very little or no effect on killing the grubs. This is because the insecticide often gets trapped in the thatch layer and never reaches the top soil. For severely thatched lawns it would be best to de-thatch or aerate the lawn prior to application.
Billbugs and their larvae can also be present around plant roots, causing equally damaging effects from the presence. Treating for billbugs around trees and plants usually means following the same practice of insecticide application, but in this case we apply to the garden bed instead of the sod, and still water it in as directed on the product packaging.
Naturally Controlling Billbugs
Biological or natural methods of controlling Billbugs include natural predators such as some wasp species, racoons and birds which often dig into the lawn looking for both Billbugs and other bugs, grubs and insects.
Parasitic Nematodes in the Steinernema and Heterorhabditis families can also be a great method of controlling Billbugs. Many Nematodes varieties can be purchases in some garden stores, online, or through mail order. Apart from the natural aspect of using Nematodes as a control method, the other great advantage to this method is that it is effective on both adult and larval Billbugs.