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Special thanks to Dr. Steve Alm, URI Department of Plant Sciences for providing assistance with demonstrations sites, and information and review of this fact sheet.

URI Master Gardener, Rudi Hempe, collects adult oriental beetles once each week from these traps (early June to late August) at the Davisville Demonstration Site.

About the Oriental Beetle (white grubs)

Chemical Control

Alternative control of the oriental beetle: mass trapping and mating disruption

About the Oriental Beetle (white grubs)
The Oriental beetle becomes an adult around mid-June and generally lays its eggs in July.

The larval stage, known as the grub, does cause considerable damage to turf grasses and nursery plants. The grubs eat and destroy the roots of the grass. They are also found in nursery stock, strawberry beds and some outside potted plants. The grubs live below the ground within the effective root zone (approximately 1 to 6 inch depth). They can stay active during a mild winter, otherwise, they usually go deeper into the soil when temperatures are cold.

White grubs exposed after harvesting turfgrass.

The Oriental Beetle grub population was at a high enough level at the Davisville Demonstration Site to warrant treatment. The majority of samples yielded a population of 10 grubs per square foot or more. This "level" is often referred to as the economic threshhold level where there are or will be adverse impact and damage to the "crop" or landscape plant.

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Chemical Control:
An application of Bayer Advanced Lawn Season-Long Grub Control was applied to infected lawn areas according to the rate and procedures specified on the product label. The label is the law. This product contains a granular formulation of the active ingredient Imidacloprid, which is the same active ingredient used in the Trade name Merit.

Generally, a granular formulation of a chemical pest control product provides less risk of exposure and losses due to leaching or stormwater runoff than other formulations such as sprays.

Drop Spreader
The granular formulation was applied using a drop spreader for accurate control. This was especially important as the product was applied to lawn areas that are near paved driveways, sidewalks, and roads.

This chemical treatment is effective against the new cycle of white grubs that hatch after the July mating period. An additional alternative control was also used at these sites to provide a second line of defense. Sampling for white grub populations occurred again in September 2003 and May 2004.

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Alternative control of the oriental beetle: mass trapping and mating disruption
One form of alternative chemical control for the oriental beetle is known as mass trapping and mating disruption. The process involves installing traps (the style being used here is known as a catch-can trap) that attract the adult male oriental beetle.

Unlike Japanese beetles, oriental beetles are not as adept at flying, so these traps must be installed below ground so that the top of the funnel (opening of the trap) is at ground level.

The adult male oriental beetle is attracted to the trap due to a lure that is placed in the upper portion of the trap. The lure contains a natural scent or sex pheromone that is emitted by the adult female beetle to attract the male for mating purposes. In this way, the mating cycle is being disrupted or interfered with.

The pheromone lure is a small rubber tube-like piece that inserts within a small hole in the above-ground portion of the trap.

Other benefits
Oriental beetles are usually only active during the evening hours. This trap and lure will also encourage the adult male beetles to come out of the ground during the day, which increases the possibility of bird predation – another natural form of pest control.

In trials on golf courses, traps have been effectively placed as much as thirty feet apart. It is possible that the oriental beetle will be attracted from as far away as over one hundred feet.

At our demonstration sites, the traps have been located within perennial beds adjacent to lawn areas, and in areas that allowed for the depth needed to install the trap below ground. Traps have been placed in areas that are mostly sunny, and in areas that hid the traps from plain view where possible. The beetles were collected and counted once each week.

The lures are effective for about six weeks--read the manufacturer instructions. They should be installed in early-mid June, as the grubs become adult beetles. The traps must be monitored and emptied about once per week. The captured beetles can be drowned in soapy water.

Costs and suppliers
One catch-can trap and lure set can cost about $17.00, not including shipping. A replacement lure can cost about $2.50 each. Costs from 2004. They can be ordered through

Great Lakes IPM
10220 Church Road, NE
Vestaburg, Michigan 48891
1 (800) 235-0285;


Trece, Inc.
P.O. Box 129
Adair, Oklahoma 74330
(866) 785-1313;

You can also do a web search on Integrated Pest Management

It is important to know exactly what type of beetle you have. Japanese beetle lures are different, trap placement will be different, and the result of this method of alternative pest control is not the same as with the oriental beetle.

For assistance with pest identification and management:
The URI Plant Protection Clinic, (401) 874-2900