Japanese Beetle (JB)

The Japanese beetle (JB), Popillia japonica, is native to Japan. Adults feed on the fruit, flowers, and leaves of a wide variety of plants, while the larvae live underground and feed on roots and decaying material, favoring grass roots. JB is most common on the northern Japanese islands of Honshu and Hokkaido. It is not common on the more southern islands of Japan because it competes with other related species and because these islands lack the abundant grasslands of the north that are conducive to JB larval feeding. It is not considered much of a pest even on the northern islands because population levels remain constrained by the cool climate, which causes the JB to have a two-year life cycle, and by a parasitic fly that is well synchronized with the JB life cycle.

In 1916, JB was discovered in a nursery in New Jersey, possibly arriving inadvertently in potted bulbs from Japan. The environment it encountered in the United States (US) was warmer than its native range, and this allowed it to complete its life cycle in only one year, leading to a more rapid population buildup than in its native range. In addition, the abundance of grass grown in lawns in urban areas provided a ready larval food source, and this combined with the absence of its main parasitic fly further allowed the fledgling infestation to grow quickly and spread. As a result, in the 100 years since it was discovered in the U.S., it has completely colonized 20 states and partially infested another 15. Its US distribution now ranges from Maine south to Georgia and westward to the Mississippi River, with additional areas scattered across the Great Plains to central Colorado. California has historically been free of JB, but has experienced the occasional infestation. These infestations have been aggressively eradicated when found, and this has allowed the state to maintain its nationally-recognized JB-free status.

No, JB is not established in California. While the JB is established in most eastern states, it is not established in California or the rest of the western US. As localized infestations are detected here, we work to isolate and eradicate them before they can become footholds that could lead to wider infestation and establishment.

The two lists below include all beetles trapped or visually collected in the environment in Sacramento County since 1987 (the earliest year for which records have been entered into the CDFA electronic records database). The lists do not include beetles found on planes during inspections.

A. High Hazard Detections - Trapped

This list summarizes the JB trapped at or just outside the two major airports for cargo planes in Sacramento County, namely Sacramento International (SMF) and Mather Field (MHF). They are presumed to be the result of JB leaving the planes upon arrival, so they normally do not trigger treatments. However, because there were five beetles in 2002 at Mather Field, the CDFA did treat the turf on the airport and 16 bordering trailer park properties with imidacloprid that year as a precaution.

B. Residential Detections - Trapped or Visual

This list summarizes the JB trapped or collected visually in residential neighborhoods outside of the high hazard airport trapping in Sacramento County.

At the project sites impartial third-party monitoring is conducted. A pesticide monitoring program is used to evaluate program effectiveness and environmental impact. Pesticide monitoring is a cooperative effort involving state and county personnel. The evaluation is designed to effectively address agency, cooperator, and public concerns.

The Sacramento County Agricultural Commissioner's Pesticide Use Enforcement staff makes regular inspections of mixing/loading, equipment and treatment activities, and pesticide container storage.

CDPR's Division of Pest Management Environmental Hazards Assessment Program staff monitor for detectable levels of pesticides in and around treatment areas. This may include sampling of air, foliage, food crops, water, soil, or other media. Monitoring results will indicate program effectiveness by measuring persistence of pesticides in pest host materials, and discover any environmental impacts by measuring residues in non-target environmental components.

CDFA has a National Pollutant Discharge Elimination System (NPDES) permit issued by the State Water Resources Control Board to ensure no pollutants are discharged into a body of water. CDFA has never failed to comply with the terms of its NPDES permit.