Japanese beetles (Popillia japonica) are highly invasive pests of more than 300 plants including some of Idaho’s top commodities. ISDA is currently implementing Japanese beetle eradication plans in two areas of Idaho (Caldwell and Pocatello).

Caldwell Eradication Program

  • 2021 – One detection trap in Caldwell, collected the first Japanese beetle specimen ever found in Canyon County.

  • 2022 – 82 JB traps were set up in Caldwell. Between July and September, 77 Japanese beetle were collected in the traps, defining an established infestation that appears to be centered in a residential area bordered by Lincoln Rd (N), Franklin Rd (S), I-84 (W) and Smeed Pkwy (E).

  • 2023 – 1,065 properties and 310 acres of turf were treated for Japanese beetles in Caldwell. Traps in Caldwell collected 260 Japanese beetles, indicating the infestation has expanded.

  • 2024 – The Caldwell treatment zone has expanded, and two rounds of Japanesebeetle treatment are planned.
  • Japanese beetles are ½ to ¾ inch long.
  • Front of body is shiny metallic green. Wing cases are coppery.
  • Body has 5 white tufts of hair along each side.
  • Adult beetles feed on the upper leaf surface, removing leaf tissue and releasing an aggregation pheromone that attracts additional beetles to the potential food source.
  • Manifested as skeletonized leaves with large, irregular holes, adults will move to devour flowers and fruits.
  • Evidence of grub (beetle larva) are often unnoticed until populations build up to levels of sufficient to kill grass roots.
  • Evidence of damage is seen when localized discolored patches appear.
  • Attracted to some of Idaho’s top commodities including hops, grapes, apples, stone fruits, vegetable crops, and nursery stock.






  • An established infestation that appears to be centered in a Caldwell residential area bordered by Lincoln Rd (N), Franklin Rd (S), I-84 (W) and Smeed Pkwy (E).


  • In 2018 one JB was captured in a Pocatello Park. Since then, trap numbers throughout the city remain low, though consistently increased for three years. 
  • Two parks where most of the beetles were captured were targeted for treatment following the protocol that was successful for JB eradication in Boise. After treatment of those parks, only 8 JB were trapped in 2022. A second treatment occurred in those parks during 2022.
  • Treatment for 2023 is planned for Pocatello Park locations.

Caldwell resident in treatment area:

  • Complete the consent formand return to ISDA by email jb@isda.idaho.gov by April 7, 2023.
  • Be on the look out for a notification about treatment, approximately one week before the pesticide application.


  • Look out for signs of Japanese beetle (see “Identifying Japanese Beetles”).
  • Report any signs of Japanese beetle to ISDA at JB@ISDA.Idaho.Gov and please provide pictures if you are able.

     See the resources below for more information on Japanese beetles in Idaho.

  • Pollinator Protection – The Idaho State Department of Agriculture takes extensive measures to ensure that all insect eradication efforts have minimal impact on bees and other pollinators.
  • Pesticides Used:
    • May application – Granular Insecticide Acelepryn G – active ingredient chlorantraniliprole, is classified by the U.S. Environmental Protection Agency as a reduced-risk pesticide. It has the lowest relative toxicity compared to other insecticides labeled for the same purpose.
    • Mid-July application – Granular Insecticide Imidacloprid – developed to mimic nicotine which is a naturally occurring compound found in many plants, including tobacco, and is very toxic to insects. Possible hazards to pollinators exist with residue in leaves and blossoms of treated plants. When applied only to turfgrass, strictly adhering to label directions, this neonicotinoid-class pesticide can eliminate the JB grub without harming bee and pollinator health and will remain a critical tool in the eradication effort (National Pesticide Information Center (NPIC), 2010).

     “Though these products have excellent safety records with the intended action plan use, ISDA will be taking extraordinary measures to ensure that pesticide applications have minimal impact on residents and the environment.” 

  • A total of 1,065 properties and 310 acres of treatable turf is planned for Caldwell in 2023
    • 3 properties owned by City of Caldwell 90 acres (estimated 60 acres treatable turf)
    • 1,060 residential or commercial properties 480 acres (estimated 240 acres treatable turf)
    • 2 school properties 20 acres (estimated 10 acres treatable turf)
  • Residents will be notified at least 1 week in advance of any treatment.
  • May application – Granular Insecticide Acelepryn G.
  • Mid-July application – Granular Insecticide Imidacloprid.
  • Each treatment will take one week to apply the larvicide.
  • If not properly eliminated, Japanese beetles have potential to be destructive to Idaho’s agriculture industry.

    • The industry would suffer losses due to decreased production of marketable fruit and plant products, increased pesticide use, and loss of markets if other states or countries enacted quarantines against Idaho products.

    • Western states and foreign countries could impose quarantine restrictions on movement of Idaho’s top agricultural commodities including hop, apple, grape, stone fruit, vegetable seed, and nursery stock.
  • Pre-Treatment:

    1) Your property is accessible to the contractor’s crew.  All applicable outside gates and entryways should be unlocked, and animals must be kept inside.

    2) Non-stationary items that can be easily moved should be removed from lawns and grassy areas.

    3) Water and food bowls for pets should be removed or covered during application.

    4) Adults, children and pets of all kinds should remain inside during the application.

    Note: Koi ponds and all water features containing fish or other aquatic animals should be tightly covered immediately before application.  The cover should be removed immediately after the treatment is completed.


    1. Thoroughly water lawn and grassy area on your property where the granular turf treatment has been applied to allow it to penetrate the soil where the grubs are feeding.
    2. After the turf treated areas are watered, allow to dry completely.
    3. Once the area is dry, people and pets may safely re-enter/ resume normal activities.

    *Please use an automated sprinkler or garden hose to water in the granular treatment, DO NOT flood irrigate.

Phone: (208) 332-8620

Email: JB@ISDA.Idaho.Gov

Address: 2270 Old Penitentiary Road, Boise, ID 83712