Pesticide use increases following four-year decline

Pesticide use increased in Fresno County and statewide during 2010 after declining for four consecutive years, California’s Department of Pesticide Regulation reports.

The greatest pesticide use occurred in the San Joaquin Valley. The top five counties in order of most pesticide pounds applied in 2010 were Fresno, Kern, Tulare, San Joaquin and Madera.

In Fresno County, farmers applied approximately 30.1 million pounds of pesticides in 2010, up from 27.8 million pounds in 2009. Kern County growers applied 25.8 million pounds of pesticides in 2010, compared to slightly less than 22 million pounds the previous year.

Tulare county farmers bucked the trend with 13.1 million pounds of pesticides applied in 2010, compared to slightly more than 14 million pounds in 2009. Farmers in San Joaquin County applied 9.4 million pounds of pesticides in 2010, up from about 8.5 million pounds in 2009.

Madera County rounded out the top five with 9.1 million pounds of pesticides applied in 2010, compared to 7.7 million pounds applied the previous year.

Data showed that Fresno County farmers preferred sulfur to treat processing tomatoes and grapes, petroleum oil and mineral oil to treat almonds and calcium hydroxide to treat oranges. Fresno county farmers applied pesticides to more than 12 million acres of farmland.

Statewide, growers boosted the number of acres treated by 15 percent, up 9.7 million acres to a total of 75 million acres in 2010. As in previous years, sulfur was the most highly used pesticide in both pounds applied and acres treated.

By pounds, sulfur accounted for 27 percent of all reported pesticide use.

Its use grew by 4.4 million pounds or 10 percent and 141,826 acres or 9 percent.

Sulfur is a natural fungicide favored by both conventional and organic farmers mostly to control powdery mildew on grapes and processing tomatoes.

Much of the pesticide treatments were on rice, walnuts, oranges almonds, grapes and strawberries.

Weather was primarily to blame for the increase in pesticides.

The winter and spring of 2009 and 2010 were relatively cool and wet, which can result in greater use of fungicides to control mildew and other plant diseases. “Summer and fall temperatures were also below average, which led to late harvests, more insect damage to some crops and additional treatments,” said Chris Reardon, chief deputy director of the Department of Pesticide Regulation.

Overall, most of the growth in pesticide use was in production agriculture where applications increased by 12 million pounds. Post-harvest treatments went up by 657,000 pounds, structural pest control by 760,000 pounds and landscape maintenance by 374,000 pounds.

Pesticides with the greatest increase in pounds applied included 1,3-dichloroopene, a fumigant whose use rose by 2.4 million pounds or 37 percent. It is used on strawberries, almonds, sweet potatoes, carrots and grapes.

The fumigant is an alternative to methyl bromide, which is being phased out under an international treaty to protect the ozone layer.

Metam-sodium also increased in use. It is used as a fumigant on carrots and processing tomatoes and potatoes.

Major crops that showed an overall increase in pounds of pesticides applied over the previous year included wine grapes, carrots, cotton, almonds and grapes. Fewer pounds of pesticides were used on rice, processing tomatoes, alfalfa, peaches, nectarines and applications to fields before crops were planted.