New Rules For Fumigant In California

Guided by a new scientific assessment of health risks, the California Department of Pesticide Regulation (DPR) has announced an update to the way the fumigant 1,3-Dichloropropene (1,3-D) is managed and used in California.


This fumigant, commonly known by the brand name Telone (Dow AgroSciences) is used to control insects, nematodes, and other organisms in the soil that threaten a variety of crops including sweet potatoes, almonds, strawberries, grapes, and carrots. It has been used in the U.S. since 1954 and in California since 1970, mostly in the San Joaquin Valley and Central Coast regions.

The new restrictions, which will take effect on Jan. 1, 2017, include:

  •  An annual limit of 136,000 pounds* within each 6-by-6 mile area known as a township. (Townships are used to track pesticide applications). Currently, township limits are between 90,250 and 180,500 pounds per year.
  •  Discontinuing the current practice of carrying forward or “rolling over” unused allocations of 1,3-D from one year for use in future years.
  •  A ban on the use of this pesticide during December, when weather conditions tend to make air concentrations higher.

California is the only state to limit how much of the pesticide can be used annually in any area. 1,3-D is also a restricted material, and as such can only be applied by trained, certified applicators under a permit from a County Agricultural Commissioner.

In the last decade, DPR’s regulations allowed growers to use varying amounts of 1,3-D in a township annually. These limits ranged from 90,250 pounds to more than 180,500 pounds provided growers used less in other years. It also allowed unused allocations of the pesticide to be carried over into the following years. As a result of these flexible limits, some growers often used more than 136,000 pounds of this pesticide annually per township. That will no longer be allowed.

More background can be found on the 1,3-Dichloropropene Regulatory Documents and Activities page.

* All pounds of 1,3-D are adjusted using application factors that include fumigation method, month, and region.