New dormant orchard spray regulations in effect

(Reprinted with permission from Summer 2006 Issue of Watershed Coalition News (WCN), a publication developed by the Coalition for Urban/Rural Environmental Stewardship (CURES) with a grant from the Almond Board of California. PDF versions of the newsletter are available at http://www.curesworks.org/newsletter.asp.)

Orchard growers in California have new regulations to follow when applying most types of dormant sprays. More than two years in the making, the new rules from the California Department of Pesticide Regulation went into effect on Aug. 17.

Driving the new regulations is the long recognized problem of dormant sprays being washed from orchards during winter rains. Runoff from two insecticides used in dormant sprays, diazinon and chlorpyrifos, prompted adoption of Total Maximum Daily Loads (TMDLs) for the Sacramento, Feather and San Joaquin Rivers.

The new label restrictions apply to all organophosphate, pyrethroid and carbamate insecticides. Exempt are dormant oil only applications or biocontrol agents such as spinosad or Bt or if the orchard is in a “hydrologically isolated site.” This site is “any treated area that does not produce runoff capable of entering any irrigation or drainage ditch, canal, or other body of water.”

Key to the new DPR regulations, called “Dormant Insecticide Contamination Prevention,” are new requirements for use of conventional insecticides when runoff cannot be contained:

• A written recommendation from a PCA is needed prior to the application;

• The application can’t be made within 100 feet of any sensitive aquatic site;

• Wind speed must be 3-10 miles per hour (mph) at the perimeter of the application site as measured by an anemometer on the upwind side.

Dormant insecticide applications are prohibited under two scenarios:

• Soil moisture is at field capacity and a storm event is forecasted within 48 hours following the application or;

• A storm event likely to produce runoff from the treated area is forecasted within 48 hours following the application.

Aerial applications will only be allowed if soil conditions do not allow field entry, or approaching bloom conditions necessitate aerial application. The three restrictions above also apply to aerial applications. If storm runoff from an orchard can reach a waterway, growers are required to divert any runoff with an on-farm recirculating system and/or hold any runoff for 72 hours before releasing into a sensitive aquatic site. A sensitive aquatic site is any irrigation or drainage ditch, canal, or other body of water in which the presence of dormant insecticides could adversely impact any of the beneficial uses of the water way.