The Japanese beetle, a highly destructive pest, feeds on over 300 plant species, causing significant damage to both turf and ornamental plants. To prevent the spread of this invasive insect and support the safe movement of nursery stock to states not yet infested, the National Japanese Beetle Harmonization Plan (JBHP) has established uniform certification guidelines.
Certification for Japanese Beetle-Free Greenhouses/Screenhouses
Growers who wish to ship plants to states classified as Category One or Two under the JBHP, or comply with other state exterior quarantines, can obtain certification as a Japanese Beetle-Free Approved Greenhouse/Screenhouse through the Michigan Department of Agriculture and Rural Development (MDARD). This certification ensures that plants are grown in a secure environment that excludes Japanese beetles at all life stages.
JBHP State Categories
Category One States: These states are currently uninfested and include those generally west of the Rocky Mountains, such as Washington, Oregon, California, Idaho, Utah, Arkansas, and Hawaii.
Category Two States: These states are either uninfested or only partially infested and include those in the central U.S., such as Montana, Colorado, New Mexico, Texas, Oklahoma, South Dakota, North Dakota, and Alaska.
Requirements for Certification
Understanding the Japanese Beetle Life Cycle
The cornerstone of an effective Japanese beetle management program is understanding its life cycle. Growers and their employees must educate themselves about the pest and its life cycle to ensure its exclusion from growing facilities.
Pre-Production Requirements
All growing media must be sterilized, except for commercially processed or prepared soilless materials.
Plants must be bare root before planting into the approved medium to ensure they are free of soil contamination.
Secure Greenhouse/Screenhouse Setup
During the adult Japanese beetle flight period (approximately June 1 to October 15), the greenhouse or screenhouse must be secured to prevent adult beetles from entering. This includes:
Ensuring all openings are properly screened with mesh sizes of 1/8 inch or smaller.
Maintaining intact screens, paying special attention to vents and repaired areas.
Implementing stop-gap measures at all entries, such as double doors, enclosed vestibules, or keeping doors locked throughout the flight period.
A negative pressure system alone is insufficient; physical barriers like tightly fitting screens are essential.
Annual Inspections and Compliance
An MDARD official must inspect the greenhouse or screenhouse before the adult flight period begins, typically between March and May. This inspection ensures that preventive measures are in place and the facility is approved as a secure area. The inspection will confirm that the space is sealed properly and all measures, including screens and door security, are intact.
Employee Awareness and Training
Employees must be trained to understand the significance of the certification and the importance of maintaining the greenhouse’s security. This includes ensuring that no Japanese beetle-contaminated material is allowed inside the greenhouse at any time. Signage should be posted to alert employees and visitors of the facility’s secure status and the specific requirements that must be upheld. Example language for the sign: “This house is screened to comply with Japanese beetle regulations. Please ensure doors are kept closed. Report any holes in screens immediately.”
Post-Production and Shipping
After the adult flight period, plants and their growing medium must be protected from possible infestation during storage, packing, and shipping. Special care should be taken to ensure certified stock is not transported into or through infested areas, unless strict safeguards are in place to preserve the identity of the plants and prevent infestation. Growers should refer to the JBHP and contact MDARD if they have any questions.
Certification and Phytosanitary Documentation
To qualify for certification, the facility must be under a compliance agreement and undergo inspection by MDARD officials before the adult flight season. Once approved, the nursery will receive a certificate with the Additional Declaration: “The rooted plants (or crowns) were produced in an approved Japanese beetle (Popillia japonica) free greenhouse or screenhouse as provided in the U.S. Domestic Japanese Beetle Harmonization Plan.” This document must accompany all shipments to Category One or Two states.
Remediation of Non-Compliance
If deficiencies are found during inspections, such as damaged screens or unapproved materials, they must be addressed before the flight period. A reinspection or photos may be required to confirm repairs have been made.
By meeting these criteria, nurseries can ensure their plants are certified as Japanese beetle-free and comply with the necessary regulations to ship to Category One and Two states, thereby preventing the spread of this invasive pest.
