Area residents chafing at grub damage

MUNISING – Michigan State University Extension officials are urging homeowners hoping to control European chafer grub damage to their lawns to inform themselves before taking action.

The larvae from European chafer beetles damage plants including turf grass, nursery stocks, clover, alfalfa and other plants by feeding on their roots. Fruits, vegetables and field crops are among the plants the can suffer damage.

European chafer beetles have been in North America since the first half of the last century, having first been found in New York. More recently, the insects have dispersed west into several states including Michigan.

“In 2007, infestations of European chafer grubs were confirmed in the Alger Heights area in Munising Township. Since then, lawn and turf damage from grubs has spread and become common in the Munising area and around the Upper Peninsula,” said Jim Isleib, with the Alger County MSU Extension Office in Munising.

Isleib said the grubs like drier places.

“Since most lawns in the central U.P. are on light-textured soils and are not watered regularly, they are more vulnerable,” Isleib said. “A number of home lawns have been completely destroyed and many more are damaged.”

In a briefing, the Indiana Cooperative Agricultural Pest Survey Program said the larvae “typically feed from July through October and may remain high in the soil profile into winter. If conditions are favorable, European chafer larvae are able to feed under the cover of snow and are the first grubs to resume feeding in the spring, as early as March.”

“Dead and dying spots in lawns where chafer flights have been observed the previous June should be suspect and this type of injury is usually visible by late summer,” the briefing said. “Relatively low level larval infestations can cause extensive root loss in containerized nursery stock.”

Isleib had a few suggestions to help homeowners make good decisions:

  • In early spring, or early September, check if grub damage is suspected by removing square-foot-sized chunks of sod and looking for the white C-shaped larvae in the roots and soil to a depth of an inch or two. If 5-10 grubs are found per square foot, consider taking action.
  • A healthy, vigorous lawn can tolerate a few grubs. If there are less than five grubs per square foot, don’t treat the lawn with grub control products. Watch the lawn for damage and make sure to fertilize properly.
  • If enough larvae are present and treatment is needed, carefully consider what product to use and when to apply it. Various products are designed to kill grubs at different life stages. Complete information can be found on the MSU Extension website at: msue.anr.msu.edu/news/all_about_home_lawn_grub_control_products_for_2013.
  • All grub control treatments must be watered into the soil with at least a half-inch of irrigation or rainfall to be effective.
  • Products containing carbaryl (such as Gardentech Sevin Lawn Insect Granules) and trichlorofon (Bayer Advanced 24-Hour Grub Killer Plus-Granular, for example) are only effective in spring before mid-May, or in fall, September through October. These products are called “curative” and reduce grub numbers, but don’t really get rid of the problem. They don’t work in summer.
  • Products containing imidacloprid (including Bayer Advanced Season Long Grub Control and Turf Revitalizer) or thiamethoxam are only effective in summer when grubs hatch from eggs. These products must be applied in June or July for maximum effect.
  • Products containing chlorantraniliprole (including Scott’s Grub-Ex-Granular) work the same way as those containing imidacloprid or thamethoxam, but are less water soluble and must be applied in early spring, not later than mid-May to be effective. When properly applied and watered in, these products provide very good control of grubs.
  • Lawns damaged by grubs can be improved after grub treatment with proper lime and fertilizer programs and watering, if possible.
  • Be sure to read and follow instructions and safety precautions found on all presicide labels before using the products.

For more information, contac the Alger County MSU Extension office at 387-2530 or msue.alger@county.msu.edu.

John Pepin can be reached at 906-228-2500, ext. 206.