The California Department of Pesticide Regulation (DPR) will host an informal public workshop to review proposed mitigation for anticoagulant rodenticides on September 24. See more details here.

Central Valley growers are battling a severe roof rat infestation affecting over 100,000 acres, with reports from Merced, Fresno, Kings and Kern counties indicating a sharp rise in populations. Rats damage crops by eating fruits and nuts, girdling tree limbs and burrowing into root zones. Rats also destroy irrigation systems and farm equipment, leading to significant economic losses.

If you are experiencing rat challenges on the farm, please share your experiences here so that we can better understand the scope of this challenge and how to support our farmers.

A California Department of Food and Agriculture (CDFA) survey revealed high rat densities on farms, with some impacted farmers capturing up to 32 rats per night. Economic on-farm losses are estimated between $109 million and $311 million, driven primarily by damaged drip lines and yield losses. For example, one grower faced a 50 percent crop loss despite exterminating up to 100 rats daily, while another spent $20,000 replacing an entire irrigation system. Researchers from UC ANR recommend an Integrated Pest Management (IPM) strategy focused on rigorous monitoring.

Informative sessions on this rat challenge will be available at the Annual CAPCA Conference in October where UC Cooperative Extension’s Roger Baldwin will be presenting Monday, October 20 in Reno, Nevada.