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Integrated Pest Management of Japanese Beetle in North Dakota (E1631 (Revised))

This publication describes the identification, biology, damage and pest management strategies for control of the Japanese beetle. In 2012, Japanese beetle was detect at several locations across North Dakota. This revised publication summarizes where it has be intercepted and is likely established in North Dakota.

Janet J. Knodel, Extension Entomologist, North Dakota State University

Charles Elhard, Plant Industries Director, North Dakota Department of Agriculture; Patrick B. Beauzay, Research Specialist, North Dakota State University


Japanese Beetle Cover
Introduction

The Japanese beetle, Popillia japonica Newman, belongs to the insect family Scarabaeidae. It is a highly destructive plant pest that feeds on more than 300 host plants, including field crops (especially corn and soybeans), ornamental trees and shrubs, garden flowers and vegetables, and turf (lawns, pastures and golf courses).

Some of the preferred host plants of adult beetles found in North Dakota are rose, apple, black cherry, cherry, flowering crabapple, plum, grapes, hollyhock, blackberry, raspberry, linden, elm and buckeye. Grubs are found primarily in the root zones of grasses, especially irrigated turf.

Once established, it can be a difficult and expensive insect pest to control. Control costs for Japanese beetle are estimated at approximately $450 million each year in the U.S.

A single Japanese beetle was caught in 2001 in Bismarck, but no beetles were caught again until 2012. That year, the Japanese beetle was detected at several locations across North Dakota.

Upon investigation, the source of the infestation was identified as one nursery that shipped Japanese beetle-infested nursery stock into North Dakota. Since that time, Japanese beetle has been intercepted every year.

Although in low numbers, Japanese beetle appears to be overwintering in some locations.

Japanese beetle has been intercepted in 15 counties and likely is established in four counties: Burleigh, Cass, Grand Forks and Ward (see map).

Map of Japanses Beetle Survey

Distribution

The Japanese beetle is native to Japan and also is found in China, Russia, Portugal, Canada and the U.S. It first was discovered in the U.S. in 1916 in New Jersey, where it was introduced accidently from Japan. Now it is established in most states east of the Mississippi River and in Kansas, Iowa, Minnesota, Montana, Nebraska, Oklahoma and South Dakota.

Japanese beetle detection trapping has been conducted in North Dakota since 1960. Some of the potential reasons the Japanese beetle has spread in the U.S. is the favorable climate, host plants are readily available, lack of natural enemies, natural movement of adults and movement via interstate commerce.

Identification

Adult: The adult Japanese beetle (Figure 1) is oval-shaped and approximately ½ inch (14 millimeters [mm]) long and ¼ inch (7 mm) wide, although some variation in size occurs. The head and thorax are metallic green, and the wing covers are typically coppery-brown bordered with green. Some individuals have coppery-purple wing covers. The antennae form a club at each end. Five patches of white hairs protrude from each side of the abdomen, and one white patch is present on each side of the last abdominal segment. This combination of traits can be used to separate Japanese beetle from other similar scarab beetles, such as the false Japanese beetle (Strigoderma arbicola), and other green plant-feeding beetles in our area.

Figure 1 Photo by P. Beauzay, NDSU Ext Entomology

Figure 1. Japanese beetle adult (P. Beauzay, NDSU Extension Entomology)

Egg: Eggs are cream-colored and usually round or oval with a diameter of 0.06 inch (1.5 mm).

Larva: Japanese beetle larvae (grubs) are C-shaped and creamy white with a brown head capsule, have three pairs of legs and are about one inch (25 mm) long when mature (Figure 2). They are difficult to identify because they are similar in appearance to other scarab grubs, such as June beetle grubs (Phyllophaga spp.). Grubs are identified using the pattern of hairs (rasters) that form a V just below the anal slit on the end of the abdomen (Figure 3). A 10-power hand lens can help see this pattern. This beetle has three larval instars.

Figure 2, Photo by D. Cappaert, Michigan State Univ, www.bugwood.org

Figure 2. Japanese beetle larva (D. Cappaert, Michigan State University, www.Bugwood.org)

Figure 3, Photo by Mike Reding and Betsey Anderson, US Dept of Ag-Ag Research Service, www.Bugwood.org

Figure 3. V-shaped raster pattern on last abdominal segment of Japanese beetle larva (Mike Reding and Betsey Anderson, U.S. Department of Agriculture-Agricultural Research Service, www.Bugwood.org)

Pupa: The pupa is an earthen cell in the soil formed by the last larval instar. It is about ½ inch (14 mm) long and ¼ inch (7 mm) wide, and cream to metallic green depending on the maturity.

Life Cycle

The beetle usually has one complete generation per year. However, in cooler climates, completing the life cycle may take two years.

In more northern states, adults emerge from early July through early August and live from four to six weeks. Males emerge a few days earlier than females. As soon as the females emerge, they release a powerful sex pheromone to attract males for mating
(Figure 4).

Figure 4, Photo by C. Elhard, ND Dept of Ag

Figure 4. Japanese beetles mating (C. Elhard, North Dakota Department of Agriculture)

Adult beetles feed on the foliage of trees, shrubs and vines. Female beetles select an egg-laying site, usually in nearby grass areas, including pastures, lawns, golf courses and cemeteries. Eggs are laid in the soil about 2 to 4 inches (5 to 10 centimeters) deep, and one to three eggs are deposited per site. Females lay a total of 40 to 60 eggs during a two- to three-week period.

Eggs hatch in 10 to 14 days. Larvae develop through three instars feeding on grassy roots and organic matter. The first instar feeds for two to three weeks and then molts into the second instar, which continues feeding for three to four weeks before molting into the third instar by mid-September.

As the soil temperature cools to about 50 F (10 C), third instar larvae move downward in the soil for overwintering. The following spring, larvae move back up and continue feeding in the grass root zone for four to six weeks until pupation. Pupae mature in about one week, and adults will start emerging in late June to continue the cycle. Adults are active during the day and can fly up to one-half mile (805 meters).

Damage

Adult beetles feed between the veins, giving the plants a skeletonized appearance (Figure 5). Delicate leaves and petals of roses can be completely consumed (Figure 6). The beetle-damaged leaves act as an aggregation site and draw in hundreds of beetles. Figure 7 shows severe foliar defoliation on buckeye by Japanese beetles.

Figure 5, Photo by S. Katovich, USDA Forest Service www.Bugwood.org

Figure 5. Leaf skeletonizing on linden (S. Katovich, USDA Forest Service, www.Bugwood.org)

Figure 6 Photo by C.Elhard, ND Dept of Ag

Figure 6. Japanese beetle damage to rose (C. Elhard, North Dakota Department of Agriculture)

Figure 7, Photo by S. Katovich, USDA Forest Service, www.Bugwood.org

Figure 7. Severe defoliation on buckeye (S. Katovich, USDA Forest Service, www.Bugwood.org)

Grubs feed on the roots and root hairs of grasses and sometimes nursery stock, corn, beans and tomatoes. Grubs are a major pest in pastures, lawns, golf courses and cemeteries. Damage symptoms appear as plant wilting, yellowing and even death. The root feeding also reduces the ability of the plant to take up water and tolerate other stresses, such as drought.

Severely damaged turf can be rolled back easily where roots were severed from grub-feeding injury. Secondary turf damage can occur from animals such as skunks and raccoons feeding on the grubs, often destroying the turf (Figure 8).

Figure 8, Phto by M. Klein, UDA Ag Res Service, www.Bugwood.org

Figure 8. Secondary turf damage by animals feeding on grubs (M. Klein, USDA Agricultural Research Service, www.Bugwood.org)

INTEGRATED PEST MANAGEMENT

Monitoring

Monitoring for Japanese beetle adults is extremely important. Monitoring is best accomplished by using traps (Figure 9) developed specifically for Japanese beetles (see Trapping in the Cultural Control section). These traps have become a valuable tool in determining where Japanese beetles have been moving.

Figure 9, Photo by C.Elhard, ND Dept of Ag

Figure 9. Japanese beetle pheromone trap (C. Elhard, North Dakota Department of Agriculture)

Trapping multiple years in areas of recent detection can confirm whether the Japanese beetle overwintered successfully. Trapping in areas where the Japanese beetle has not been found can document new infestations or help determine how Japanese beetle move to new areas. In both cases, focused control efforts can be applied to eradicate Japanese beetles or limit them to isolated areas if eradication efforts prove unsuccessful.

Put out traps prior to adult emergence. The predicted emergence time for North Dakota is early July. Emergence timing depends on the spring and early summer soil temperatures; warm temperatures lead to earlier emergence and cool temperatures facilitate later emergence.

Cultural Control

Trapping is a cultural control strategy that produces mixed results. Japanese beetle traps (Figure 9) contain floral attractants and the female sex pheromone to lure in adult beetles of both sexes. Thus, trapping can reduce adult feeding damage and egg-laying. The attractants can lure in beetles from about 0.62 mile (1 kilometer). However, traps attract about 25 percent more beetles to an area than are trapped. The result is potentially more beetles feeding on nearby plants.

However, if establishment has occurred in North Dakota, it is probably in small, known areas. If this is the case, then trapping may be an effective strategy for eliminating or containing establishment to these areas. In this scenario, trapping will be most effective when many traps are placed throughout the suspected infested area. Traps should be distributed in mid- to late June.

Traps should be monitored at least weekly throughout the adult flight period. Traps that are cleaned and maintained with fresh lures on a regular basis are more effective than traps that are neglected.

Habitat modification is another cultural control strategy. Habitat modification involves the use of plants that are resistant or unattractive to Japanese beetle adults. In Table 1, ornamental woody plants commonly grown in North Dakota that are resistant (or unattractive) and susceptible to adult feeding, with 5 being the most resistant and 1 being most susceptible, are listed. The table is modified from tables in Held (2004), “Relative Susceptibility of Woody Landscape Plants to Japanese Beetle,” Journal of Arboriculture 30(6), pp. 328-335.

Table 1. Resistant and susceptible woody ornamentals commonly grown in North Dakota.

Resistant or Unattractive

Common Name

Rating

Scientific Name

Arborvitae

4

Thuja occidentalis

American bittersweet

5

Celastrus scandens

American elder

4

Sambucus canadensis

American hazelnut

4

Corylus americana

Black locust

4

Robinia pseudoacacia

Boxelder

4

Acer negundo

Bur oak

4

Quercus macrocarpa

Burning bush

4

Euonymus alatus

Dogwood

5

Cornus spp.

European cranberrybush

4

Viburnum opulus

Forsythia

5

Forsythia spp.

Hydrangea

5

Hydrangea spp.

Juniper

4

Juniperus spp.

Lilac

5

Syringa vulgaris

Paper birch

5

Betula papyrifera

Pear

4

Pyrus communis

Pine

5

Pinus spp.

Rhododendron

4

Rhododendron spp.

River birch

4

Betula nigra

Silver maple

5

Acer saccharinum

Spruce

5

Picea spp.

White poplar

5

Populus alba

Yew

5

Taxus spp.

Susceptible

American cranberrybush

3

Viburnum trilobum

American elm

1

Ulmus americana

American linden*

1-3

Tilia americana

American mountain ash

1

Sorbus americana

American plum

1

Prunus americana

Apple

1

Malus spp.

Black walnut

1

Juglans nigra

Buckeye

2

Aesculus spp.

Chokecherry

3

Prunus virginiana

Crabapple*

1-3

Malus spp.

European white birch

2

Betula pendula

Grape

1

Vitis spp.

Hawthorn

3

Crataegus spp.

Larch

2

Larix spp.

Lombardy poplar

1

Populus nigra

Norway maple

1

Acer platanoides

Rose

1

Rosa spp.

Sugar maple

3

Acer saccharum

Willow

2

Salix spp.

*Susceptibility variable depending on variety.

Biological Control

Nematodes are an effective biological control agent of grubs. The species Heterorhabditis bacteriophora and Steinernema glaseri are commercially available. These species actively seek and attack grubs. Another commercially available species, Steinernema carpocapsae, is less active and may not give comparable control.

Treatment timing should coincide with the end of the adult flight period (August). Applications are made to the soil and should be made near dawn or dusk when daily temperatures are relatively low. Treated areas should be watered before and after application, and periodically through the remainder of the season, to ensure that the soil habitat does not become too dry.

Nematodes have a short shelf life, so be sure to apply them as soon as they are received. Recent studies have demonstrated a synergistic effect between H. bacteriophora nematodes and the insecticides imidacloprid and chlorantraniliprole.

When purchasing nematodes, be sure to read the label to make sure you are purchasing the proper species.

Milky spore disease affects grubs and is caused by the bacterium Paenibacillus popilliae. Grubs become infected when they ingest the bacterium. Ingestion of the bacterium causes fat depletion and leads to mortality. Infected grubs have milky-white body fluids.

Research has demonstrated that the use of milky spore disease often does not provide adequate grub control. This may be due to a lack of persistence of the bacterium in the soil and/or loss of virulence. No milky spore disease products are registered for use in North Dakota.

Insecticidal Control

Proper insecticide application timing is critical to achieve maximum control of Japanese beetle adults and grubs. Because the Japanese beetle is not yet established in North Dakota, when adult emergence would begin is not known. In Minnesota, adults typically emerge in early July, and this timing should be close to what we could expect in North Dakota.

Adults can be controlled with a number of foliar-applied insecticides (Tables 2 and 3). Foliar application should commence when adult beetles are first observed feeding. Foliar-applied insecticides do not offer season-long protection, and multiple applications may be needed during the adult flight period.

The synthetic foliar-applied insecticides listed in Table 2 offer residual control that should last about two weeks. The botanical insecticides listed in Table 4 may offer only three to four days of residual activity. Azadirachtin may act as a feeding deterrent only and not cause adult mortality.

Systemic insecticides for adult beetle control are available as soil-drench and tree-injection applications to protect ornamental trees and shrubs, including roses. Systemic insecticides offer season-long control but take longer to work because the insecticide first must be absorbed and translocated through the plant. Systemic insecticides should be applied at least one month prior to adult emergence.

Grubs are best controlled in late summer after egg hatch has begun and before grubs burrow deep into the soil to overwinter. Grub control in the spring may not be effective because the grubs are larger and feeding is less extensive.

A wide range of long-lasting systemic grub-control products are available. Be sure to apply grub-control products over the entire lawn. A number of grub-control products are available to nurseries to treat existing bagged or potted nursery stock, and to treat soil before plants are bagged or potted.

The following tables list insecticides registered for use in North Dakota for control of Japanese beetle adults and larvae. Table 2 lists insecticides available to homeowners for use on lawns, fruit trees, ornamental trees and shrubs, and vegetable gardens. Table 3 lists insecticides available to professional applicators for use in residential areas, nurseries, sod farms, tree farms and golf courses. Table 4 lists botanical insecticides and biological control products for use by homeowners and professionals.

The chemical name, examples of the trade names and the Insecticide Resistance Action Committee (IRAC) mode of action group number are provided in each table. If multiple treatments are needed, we recommend rotating treatments with different modes of action to prevent or delay the development of resistance to individual insecticides. The tables also indicate the sites where individual insecticides can be used, and which Japanese beetle life stages are controlled.

Listing all available trade names for all insecticides is impractical because so many individual products are available. We recommend you bring this publication with you when purchasing insecticide products so you can be sure you are selecting a product with the recommended active ingredient to control the targeted beetle life stage, and the product is registered for use on the intended site. All of this information is listed on the product label.

As always, be sure to read, understand and follow all directions on the label. For applications to fruit trees and vegetable gardens, be sure to follow the preharvest interval listed on the product label.

Table 2. Insecticides for use by homeowners for control of Japanese beetle.

Active Ingredient

Example Trade Name(s)

IRAC Group

Adults

Grubs

acephate

Ortho Systemic Insect Killer

1B

O

beta-cyfluthrin + imidacloprid

Bayer Advanced Complete

3A + 4A

L, O

L

bifenthrin

Ortho Bug-B-Gon Max

3A

F, L, O, V

carbaryl (granular)

Ortho Bug-B-Gon

1A

L

carbaryl (liquid)

Bayer Advanced, Bonide

1A

F, O, V

chlorantraniliprole

Scott’s GrubEx

28

L

cyfluthrin

Bayer Advanced Powerforce

3A

F, L, O, V

esfenvalerate

Ortho Bug-B-Gon Garden & Landscape

3A

O, V

halofenozide

Spectracide Grub Stop

18

L

imidacloprid (granular)

Bayer Advanced Grub Control

4A

L

imidacloprid (granular)

Ferti-Lome Tree & Shrub Systemic

4A

O

imidacloprid (liquid)

Gordon’s Grub No More

4A

L

imidacloprid (liquid)

Ortho Max Tree & Shrub Insect Control

4A

O

lambda-cyhalothrin

Bonide DuraTurf

3A

L

L

lambda-cyhalothrin

Spectracide Triazicide

3A

L, O, V

malathion

Ortho Max Malathion

1B

F, O, V

malathion + carbaryl

Gordon’s Liquid Fruit Tree Spray

1B + 1A

F, O

permethrin

Bayer Advanced Complete Dust, Ortho Bug-B-Gon Dust

3A

F, O, V

trichlorfon

Bayer Advanced 24-Hour Grub Killer Plus

1B

L

F = fruit trees, L = lawns, O = ornamental trees and shrubs, V = vegetable gardens

Table 3. Insecticides for use by professional applicators in residential areas, nurseries, tree farms, sod farms and golf courses.

Active Ingredient

Example Trade Name(s)

IRAC Group

Adults

Grubs

acephate

Orthene T, T&O 97

1B

O

bifenthrin

Onyx, Talstar-P

3A

L, O

bifenthrin

*Onyx Pro

3A

GC, L, N, O, SF, TF

NS

bifenthrin

Talstar Nursery Granular

3A

NS

bifenthrin

*Brigade 2EC

3A

SF

carbaryl

Sevin SL

1A

O, TF

GC, L

chlorpyrifos

*Nufos 4E

1B

SF

cyfluthrin

Decathlon 20 WP

3A

O, N

deltamethrin

Deltagard T&O 5SC

3A

L, O

deltamethrin

*Deltagard GC

3A

GC, L, N, O, SF

dinotefuran

Safari 20SG

4A

N, NS, O, TF

halofenozide

Mach 2 1.5G, Mach 2 2SC

18

GC, L, TF

imidacloprid

Marathon II

4A

N, NS, TF

imidacloprid

Merit 2.5G

4A

O

imidacloprid

Merit 75WP

4A

O

L, SF

imidacloprid

Merit Tree Injection

4A

O, N, TF

lambda-cyhalothrin

Scimitar CS

3A

L, O

lambda-cyhalothrin

*Scimitar GC

3A

GC, L, N, O, SF

permethrin

*Perm-UP 3.2EC

3A

N, O,

thiamethoxam

Meridian 0.33G, Meridian 25WG

4A

O

GC, L, SF

* Restricted-use pesticide

GC = golf courses, L = lawns, N = nurseries, NS = nursery stock (containerized),
O = ornamental trees and shrubs, SF = sod farms, TF = tree farms

Table 4. Botanical insecticides and biological control products for use by homeowners and professionals.

Active Ingredient

Example Trade Name(s)

IRAC Group

Adults

Grubs

azadirachtin

Aza-Direct

UN

F, O, V

azadirachtin

Ecozin Plus 1.2% ME

UN

F, V

pyrethrins + piperonyl butoxide

EverGreen EC 60-6

3A

F, O, V

predatory nematodes

NemaSeek

GC, L

F = fruit trees, GC = golf courses, L = lawns, O = ornamental trees and shrubs,
V = vegetable gardens

What to Do If You Find a Suspected Japanese Beetle Adult or Grub

Because Japanese beetle establishment has not been confirmed in all counties of North Dakota, reporting suspected Japanese beetle findings to NDSU Plant Diagnostic Laboratory is extremely important. Take the following steps:

  1. Collect the specimen(s) and place them in a liquid-tight vial of 70 percent rubbing alcohol.
  2. Record the exact collection location, collection date and name of collector.
  3. Record the host plant(s) on which the beetles were found or type of grass for grubs (for example, lawn, golf course, sod farm).
  4. Count or estimate the total number of individual beetles that were observed.
  5. You may provide photographs of the plant damage, but photographs of specimens are not a substitute for the specimens. Having physical specimens is very important.

Specimens and data should be sent to:

Mailing Address (USPS):

NDSU Plant Diagnostic Lab
NDSU Dept. 7660
P.O. Box 6050
Fargo, ND 58108-6050

Shipping Address
(UPS, FedEx, etc.):

NDSU Plant Diagnostic Lab
306 Walster Hall
Fargo, ND 58102

Telephone: 701-231-7854

Visit us

Shipping Nursery Stock

The U.S. Department of Agriculture's National Plant Board and the nursery industry support the continuing harmonization of Japanese beetle quarantine and certification requirements. The Japanses beetle harmonization plan (JBHP) was developed as a framework to protect uninfested state while providing nursery stock shippers with consistent, easy-to-understand certification requirements. For nurseries that want more information, contact the JBHP.

Photo Clemson University--USDA Cooperative Extension Slide Series, www.Bugwood.org

Japanese beetle damage to rose (Clemson University - USDA Cooperative Extension Slide Series, www.Bugwood.org)

Selected References

Held, D.W. 2004. Relative susceptibility of woody landscape plants to Japanese beetle (Coleoptera: Scarabaeidae). Journal of Arboriculture 30(6): 328-335.

Krischik, V. and D. Maser. 2011. Japanese beetle management in Minnesota. University of Minnesota Fact Sheet WW-07664.

Potter, D.A. and D. W. Held. 2002. Biology and management of the Japanese beetle. Annual Review of Entomology 47: 175-205.

Shetlar, D.J. 2001. Control of Japanese beetle adults and grubs in home lawns. The Ohio State University Fact Sheet HYG-2001-03.

United States Department of Agriculture, Animal and Plant Health Inspection Service. 2007. Managing the Japanese Beetle: A Homeowner’s Handbook. Program Aid 1599. 16 pp.

 

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Printing costs provided by North Dakota Department of Agriculture, Doug Goehring, Agriculture Commissioner

May 2017

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