By Peter B Goodell
Cowpea aphids
Chlorpyrifos (Lorsban and other products containing this active ingredient) plays an important role in the management of critical key pests in alfalfa forage. In particular, blue aphids, cowpea aphids and weevils were identified by the Alfalfa Crop Team of the Critical Use of Chlorpyrifos in Alfalfa, Almond, Citrus and Cotton Project. The full report can be found by clicking here and notes that the critical alfalfa pests (weevils, blue and cowpea aphids) have few or no alternative management options to chlorpyrifos. Since the report was published in November 2014, several new insecticide registrations (including issuance of a special local needs (SLN) use) have become available. While there are alternative practices and insecticides for most pests in alfalfa, chlorpyrifos will remain an important tool in the IPM toolbox.
New regulations on the use of chlorpyrifos have been issued by California Department of Pesticide Regulation. Highlights are provided below and details are available by clicking here:
"Effective July 1, 2015, the Department of Pesticide Regulation (DPR) will designate chlorpyrifos a California restricted material when it is an ingredient in a pesticide product labeled for use in the production of an agricultural commodity. Applicators that wish to purchase, possess, or apply affected chlorpyrifos products must obtain a restricted materials permit from their local County Agricultural Commissioner (CAC). Pesticide dealers can't sell California restricted materials unless the buyer has a CAC-issued permit. Applications made for hire require a written recommendation from a licensed pest control adviser or the equivalent from a certified private applicator. There are currently 31 agricultural use chlorpyrifos products registered in California."
"Currently, DPR is developing recommended interim permit conditions based on human health and environmental risks. These permit conditions will likely include buffer zones near sensitive sites, good management practices to reduce drift or offsite movement into the air, and measures to reduce runoff into surface waters. DPR plans to issue a letter to CACs within the next month with recommended permit conditions."
"Chlorpyrifos products were designated restricted materials due to potential human health and surface water concerns. U.S. EPA recently released a draft revision of its human health risk assessment of chlorpyrifos, and federal review is continuing. DPR is conducting its own extensive risk evaluation that considers California's unique and diverse growing conditions. Measures aimed at protecting human health and the environment may be amended after the risk assessment and risk evaluation are complete. Permit conditions may change accordingly."
Source:ucanr.edu