Hull split in almonds critical time for use of Chlorpyrifos

Chlorpyrifos is used at hull split in almonds to control Navel orangeworm and Peach twig borer.

DPR proposes Chlorpyrifos change to restricted-use pesticide

Chlorpyrifos is used on major California crops. DPR concern is based on air monitoring studies.    

The California Department of Pesticide Regulations wants to make the active ingredient Chlorpyrifos a restricted use pesticide and has opened up a 45-day public comment period on the proposal.

The public comment period opens Sept. 26 and closes Nov. 12. Written comments must be received no later than 5 p.m. Nov. 12.

The move would require that trained, licensed professionals obtain a permit from their local county agricultural commissioner to utilize the material.

Chlorpyrifos is used to control pests that threaten more than 60 different crops, including alfalfa, walnuts, oranges, cotton, and grapes.

The proposed regulation would affect about 30 products used in agriculture.

DPR’s concern is once the product is applied to the field it has a propensity to move from the site of application via air and water. Excessive exposure to Chlorpyrifos in air may cause nausea, dizziness and, at very high exposures, respiratory paralysis. In water, Chlorpyrifos may be toxic to freshwater fish, aquatic invertebrates and marine organisms.    

Since 2004, between one million and two million pounds of Chlorpyrifos has been applied each year in California.

DPR’s proposed regulation would mean that all Chlorpyrifos products registered for production agricultural use must adhere to the standard requirements for all California restricted materials. This means:

  • Applications must be made or supervised by a certified applicator.
  • Purchase, possession, or use requires the property operator to obtain a permit from the county agricultural commissioner.
  • Businesses require a recommendation from a DPR licensed pest control adviser.

Public comment on the proposal may be made one of three ways:

  • Via e-mail: [email protected].
  • Via fax: (916) 324-1451.
  • Written comments may be submitted to: Linda Irokawa-Otani, Regulations Coordinator, Department of Pesticide Regulation, 1001 I Street, P.O. Box 4015, Sacramento, California 95812-4015.

For details see:

Additional information can be found at:

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