Insecticides have long been important tools for California farmers to combat agricultural pests. By 1995, organophosphate (OP) insecticides such as chlorpyrifos, azinphos-methyl, methamidophos, phosmet and diazinon accounted for an estimated 34% of worldwide insecticide sales, and they are widely credited with allowing large yield increases in commercial agriculture. The U.S. Food Quality Protection Act (FQPA), signed into law in 1996, established a new human health–based standard that “reasonable certainty of no harm will result from aggregate exposure to the pesticide chemical residue.” When the FQPA was passed, 49 OP pesticides were registered for use in pest control in the United States; since then, many uses have been canceled and others are expected to be lost, with particular significance for California growers. A number of alternative pest-control products and strategies are available, with varying degrees of effectiveness and cost. Research and development of control measures to replace OP insecticides must be pursued to maintain an economically viable state agricultural industry.

The recent invasion of California by the olive fruit fly has the potential to devastate commercial olive production throughout the state. Fortunately, much is known about this pest in Europe, and prospects for olive fruit fly control in Calif-ornia are good. Effective manage-ment is likely to result from careful monitoring and properly timed chemical control. Suppression of olive fruit fly populations on ornamental and residential olive trees using biological control may also contribute to overall control.

The direct management of insect pests using pheromones for mating disruption, or “attract and kill” approaches, can provide excellent suppression of key lepidopteran pests in agriculture. Important successes to date include codling moth in pome fruit, oriental fruit moth in peaches and nectarines, tomato pinworm in vegetables, pink bollworm in cotton and omnivorous leafroller in vineyards. Large-scale implementation projects have yielded significant reductions in pesticide use while maintaining acceptably low crop-damage levels. Because of some difficulties with high populations of pests, these programs should not be viewed as stand-alone strategies but rather as one tactic within a suite of integrated pest management options.

Effective Jan. 1, 2018, the California Department of Pesticide Regulation enacted a regulation regarding the use of pesticides near public K-12 schools and licensed child day care centers, including a provision that bans specific types of applications, including air-blast and air-assist, during weekday school hours (6 a.m. to 6 p.m.) to provide an additional safety margin for pesticide exposure beyond those provided by other regulations. We considered the financial effect on almond growers in nine counties, accounting for four-fifths of total almond production in 2014, if they had been unable to complete a standard spring disease management program on any buffer zone acreage. Results indicated that total annual losses for those counties if such a regulation had been in effect would have been $8.7 million, with per-acre losses ranging from 22% to over 50% of total operating costs, depending on the county. However, using a methodology that took into account historical weather and soil hydrologic group data, we estimated average annual losses in the nine counties among almond growers would have been under $0.2 million because the regulation would have affected the number of sprays completed for relatively few acres in relatively few years.