California growers used fewer highly toxic chemicals, including fumigants, in 2005, according to a report recently released by the California Department of Pesticide Regulation in Sacramento.

DPR tentative statistics for 2005 show 194 million pounds applied for all commercial uses, compared with 180 million pounds in 2004. Half of the increase was attributed to sulfur, a natural compound used by organic and conventional growers to combat mold and mildew. Wet weather was a factor for many growers in 2005.

At the same time, use of many higher-risk chemicals declined, both in pounds applied and acres treated, while use of some reduced-risk compounds increased dramatically.

"The number of pounds applied is not as significant as the chemicals that contribute to that total," says CDPR director Mary-Ann Warmerdam. "Increased use of less toxic materials shows that we are moving in the right direction."

As in previous years, most farm pesticide use occurred in the San Joaquin Valley, the nation's No. 1 agricultural area. Fresno, Kern, Tulare, San Joaquin, and Madera counties had the highest use, asmeasured in pounds.

Pesticide use varies from year to year based on many factors, including types of crops, economics, acreage planted and weather. A cool, wet spring in 2005 promoted fungus and other diseases in crops such as grapes, requiring more intensive pest management. 

  • As measured in pounds, the most used pesticides were sulfur, petroleum oils, metam-sodium, 1,3-dichloropropene (1,3-D), and mineral oil. Sulfur use increased by 7.3 million pounds—13 percent—and was the most highly used pesticide in 2005, both in pounds applied and acres treated. By pounds, sulfur accounted for 32 percent of all reported pesticide use.


  • Fumigant use decreased in pounds applied from 2004 to 2005—1 million pounds, 2.5 percent—and decreased in cumulative acres treated—54,000 acres, 14 percent. Use of about half of the major fumigants decreased in pounds but nearly all major fumigants decreased in acres treated.


  • Pounds of reduced-risk pesticides increased by 630,000 pounds applied—60 percent and by 2.4 million acres treated—39 percent.


  • Crops that showed an overall increase in pesticide pounds applied from 2004 to 2005 included winegrapes, oranges, raisin and table grapes, walnuts and almonds. Major crops or sites with decreased pounds applied included rice, fresh tomatoes, strawberries and lemons.