The Palisade Colorado Japanese Beetle Eradication Program Colorado State University Extension Mesa Delta Montrose and Ouray Counties

Japanese beetle trapping has been conducted in western Colorado for many years, with the only captures associated with imported nursery stock. Past captures of mostly individual specimens were from Mesa, Jefferson, Boulder, and Larimer Counties. This eastern pest was not thought to be able to survive in our dry climate because grubs require moist soil conditions. Dry winters had been thought to limit or possibly eliminate any populations. Moisture conditions associated with irrigated lawns, however, may be sufficient to allow for survival of Japanese beetle larvae.

An infestation of Japanese beetles Popillia japonica was identified in Palisade (Mesa County) in the summer of 2002. The initial discovery was based on a single adult Japanese beetle taken to Bookcliff Gardens, and forwarded to the Extension office on July 23. The identification was verified by Dr. Boris Kondratieff, entomologist at Colorado State University on July 24. A series of Japanese beetle traps were placed in the vicinity of the initial beetle capture in Palisade during the last week of July, 2002 by Colorado Department of Agriculture personnel. Eighty-five beetles were captured over the course of the following two weeks. Initial survey results indicate that the Palisade infestation is confined to a 10 block area of Palisade . Eradication attempts in California, Nevada, Idaho and Oregon have been successful in the past. It is critical to identify breeding sites for eradication attempts to be successful.

During the summer of 2003 a mass trapping program was implemented by the Colorado Department of Agriculture. This program continued through September and a total of 1218 adult Japanese beetles were captured. In conjunction with this effort, the Colorado State University Extension placed traps throughout Mesa county. No Japanese beetles were captured indicating that the area of infestation was confined to the town of Palisade.

This summer (2005) a more directed effort will be implemented to eradicate the Japanese Beetle from Palisade. The Japanese Beetle Eradication Committee has developed a three pronged approach based on the success and failures of past eradication efforts. Not only will the committee utilize mass trapping, but will also use a targeted larval insecticide and lawn dry down in an attempt rapidly eliminate the Japanese beetle from the Palisade area.

The beetle is damaging to plants in both the adult and white grub stages. The adults chew leaves of over 300 kinds of plants, feeding between the main veins causing a lacy 'skeletonizing' type of injury. Among the most commonly damaged plants are: grapes, apples, peaches, cherries and plums among the fruits; asparagus, beets, broccoli, beans and sweet corn among vegetables; and Norway maple, linden, crabapple, purple-leaf plum, and rose. Adults also readily feed on rose blossoms and are very damaging.

However, Japanese beetle is also very damaging in the larval stage, occurring as a white grub that feeds on roots of turfgrasses. It is considered to be the single most important turfgrass-infesting white grub in North America and will develop on all of the kinds of cool season turfgrasses that are normally grown in Colorado.

The Japanese beetle is also an insect of great regulatory concern. Many states impose restrictions on items coming from areas known to be Japanese beetle infested. Because of the reproducing population in Palisade it is much more difficult, for example, for nursery producers to ship materials to Utah, California and other states where Japanese beetle is not established. Eradication of Japanese beetle will eliminate this barrier to shipment of Colorado nursery items that are restricted from infested areas.

The adult Japanese beetle is a little less than 1/2 inch long and has a shiny, metallic-green body and bronze-colored outer wings. The beetle has six small tufts of white hair along the sides and back of its body under the edges of its wings. The males usually are slightly smaller than the females. You are most likely to see the adults in mid summer. During the adult feeding period, females intermittently leave plants, burrow about 3 inches into the ground--usually into turf--and lay a few eggs. This cycle is repeated until the female lays 40 to 60 eggs. By mid to late summer, the eggs hatch, and the young grubs begin to feed. Each grub is about an inch long (approximately 23 mm) when fully grown and lies in a curled position. In late autumn, the grubs burrow 4 to 8 inches into the soil to just below the frost line and remain inactive all winter. This insect spends about 10 months of the year in the ground in the larval stage. In early spring, the grubs return to the turf and continue to feed on roots until late spring, when they change into pupae. In about 2 weeks, the pupae become adult beetles and emerge from the ground. This life cycle takes a year.

Please note that there are many other white grubs common to the Palisade area. If you find white grubs in your lawn DO NOT PANIC. It does not necessarily mean that you have a Japanese beetle infestation. Japanese beetle larvae are only about an inch long when fully grown. If you find grubs that are larger than one inch it is most likely not a Japanese beetle larva. If you have questions about white grubs that you find please contact the Japanese Beetle Coordinator.

Relative sizes of turfgrass-infesting scarabaeid grubs. Clockwise: the black turfgrass ataenius (smallest), the Asiatic garden beetle, the Japanese beetle, the oriental beetle, the European chafer, the northern masked chafer, the May or June beetle, and the green June beetle (largest). (Drawn by H. Tashiro, NYSAES, Cornell University)

** NOTE: If you find whitegrubs in your lawn there is a chance that they are not Japanese beetles. The masked chafer is commonly found in the Palisade area. Just before pupation (April-June), the Japanese beetle white grub is only about an inch long when laid flat. The masked chafer, on the other hand, will measure an inch and a half or more when laid flat.

Mass trapping beetles has been used in every successful eradication effort. As such, trapping will play a key role in the Palisade eradication effort as well. This method is a very effective way to eliminate the adult stages of the beetle. It is of extreme importance to get the traps out as early as possible. If they are in placed early enough there is a good chance of catching the female beetle before she has a chance to lay her eggs. Trapping is also central to monitoring the spread of the Japanese beetle and in evaluating the success of the eradication effort.

The traps contain no insecticides. They can be safely handled and pose no threat to humans or non-target animals. One lure that will used to attract the beetle is made up of chemicals found in flowers. Specifically, a 3:7:3 mixture of phenethyl propionate + eugenol + geraniol (PEG). Both sexes of the beetle are highly attracted to this mixture. The other lure to be used is based on the chemical pheromone that the adult female beetle uses to attract a mate. This lure is only attractive to the male Japanese beetle

For the eradication project we will be attempting to place a trap in every yard in Palisade. The more traps that can be sued in the core area of infestation the better for the eradication goal.

There will be no cost to the homeowner. The Eradication project will provide the trap, monitor for the beetle, and do all needed maintenance.

The Palisade eradication project is attempting to attack the beetle during every treatable stage. After considerable research imidacloprid had been chosen for the eradication project. Imidacloprid is a newly registered insecticide that has been very extensively studied for human health risks. As a result of these studies imidacloprid has been allowed registration on a very wide variety of food crops. Indeed, in its consideration for registration it has been considered a "reduced risk" insecticide with substantially lower health and environmental risks associated with it than did the insecticides it has come to replace.

The cautionary statements on the label for Merit, the imidacloprid formulation applied for turfgrass, contains the "Caution" statement, reflecting low risk. ("Warning" or "Danger/Poison" appear on labels that involve products with higher risks.) The Material Safety Data Sheet (MSDS) for Merit 75W can be accessed at http://www.cdms.net/ldat/mp881006.pdf.

Imidacloprid has been shown to be very effective for control of Japanese beetle larvae. It has a low toxicity to warm blooded animals and minimal risk of adverse environmental effects. Currently, imidacloprid is widely used on food crops and has many veterinary uses and is commonly used on pets.

Every property owner in the town of Palisade that has signed a permission slip will receive a no-cost application of Merit during early June.

Permission slips can be picked up and dropped off at the Palisade town hall, Chamber of Commerce, and public library. Permission slips are also available at the Department of Agriculture Insectary in Palisade. It is essential that a permission slip for your property be turned in by May 14th. This will allow plenty of time to get the traps in place and prepare for the larval insecticide application. If you click here you can print your own permission slip. Please turn your permission slip in as soon as possible to one of the following locations:

Homeowners living outside of the Palisade city limits who wish to treat their lawns for white grubs can purchase imidacloprid based granular insecticides at most local garden centers, hardware, and home improvement centers. It is sold as Bayer Advanced Lawn Grub Control RTU Granules or Merit 0.5G . These granular materials should be applied in mid to late June. Follow label directions for the proper use rate. A second white grub insecticide, Mach 2, contains the active ingredient halofenozide. This material has given good grub control when applied in a timely fashion. Halofenozide mimics an insect growth hormone and interferes with the molting process. It must be injected by small larvae to be effective. Mach 2 granules should be spread during late June or early July for maximum effectiveness.

Homeowners outside of the Palisade city limits who find adult Japanese beetles should contact Matt Camper at 250-2694.

Soil moisture is extremely important in the life history of Japanese beetle. Eggs and 1st stage larvae are very susceptible to death by drying. Female beetles will not lay eggs in dry soil and survival is very poor for eggs laid in soils that later become dry. In the midwest where Japanese beetle is very common and well established, its numbers may vary greatly from year to year in response to summer rainfall patterns.

Allowing soil to dry between irrigations can be very effective in reducing populations. The irrigation, supplemented with the larval insecticide treatments, will be a one-two punch that should be very important in being able to rapidly eradicating the larval stages of the Japanese beetle. The insecticide will need to watered in!

It would be most desirable if the homeowner would follow a schedule of infrequent (once a week), but deep watering (to the depth of a normal screw driver). This would allow the soil to dry between waterings but provide sufficient moisture to maintain the lawn. For more information on watering lawns, check out the web pages at http://www.coopext.colostate.edu/TRA/PLANTS/turf.html. Give the Colorado State Office in Grand Junction a call at 244-1834 if you need additional information or guidance.

Placed on the Internet April 13, 2004 9:54 PM

WebMaster Dr. Curtis E. Swift, Area Extension Agent, Horticulture
Colorado State University Extension
2775 US Hwy 50, Grand Junction, CO. 81503
voice: 970-244-1834
fax: 970-244-1700


Eggs	Larva	Larva

Pupae	Adult