Changes in pest management practice in almond orchards during the rainy season in California, USA

Abstract

In California, regulatory agencies are concerned about organophosphate (OP) contamination of surface water. OPs originate in part from applications on dormant almond and stone fruit orchards that are washed off during winter rainstorms. Programs conducted by the University of California Statewide Integrated Pest Management Project, University of California Cooperative Extension, and the Biologically Integrated Orchard Systems (BIOS), a coalition of public and private groups, have promoted the replacement of OPs on almonds during the rainy season with alternative practices. Data from individual applicator records from the California Pesticide Use Reports demonstrated that during 1992-1997, almond growers in all nine major almond-producing counties significantly reduced use of OPs. The area of almond orchards treated with OPs during the dormant season was reduced by 40-55%, depending upon the region. Similarly, the percentage of growers who used OPs during the dormant season was reduced by 31-48%, and the mass of OPs applied to almond orchards during the dormant season was reduced by 22-57%. During the same period, there was a significant increase in the percentage of growers who used "reduced-risk" treatments: the microbial pesticide Bacillus thuringiensis at bloom-time, oil without an insecticide during the dormant season, and no treatment during the dormant or bloom season. In addition to the decrease in OPs during the dormant season, there was a significant decrease in the area treated with OPs during the growing season. However, there was also a significant increase in the use of pyrethroids during the dormant season, a practice that might result in some surface water and sediment contamination.

PATTERNS OF PESTICIDE USE IN CALIFORNIA AND THE IMPLICATIONS FOR STRATEGIES FOR REDUCTION OF PESTICIDES

“…We found no examples for plant diseases or for herbicide reduction. However, there are a few examples from California in which use of organophosphates (OPs) has been reduced, primarily by substitution with pyrethroids (18,19). Even with the far greater number of IPM programs for insects than diseases, examples of declines in insecticide use during our study period were relatively infrequent.…”

Diazinon Accumulation and Dissipation in Oryza sativa L. Following Simulated Agricultural Runoff Amendment in Flooded Rice Paddies

“…California's concerns with diazinon nonpoint source contamination in agricultural surface waters is well documented (Domagalski 1996;Kratzer 1999;Epstein et al 2001;Holmes and de Vlaming 2003;de Vlaming et al 2004;Joyce et al 2004;Schiff and Sutula 2004;Brady et al 2006). Particular examples known in the literature are the Central Valley, including Sacramento and San Joaquin rivers, and Imperial Valley, including Alamo and New Rivers.…”

Fifty Years Since Silent Spring

“…Despite the concern expressed here that IPM in the field is promoted to the public as focused on pesticide reduction but in practice is focused on either maximizing pest control or grower profits, there are documented cases of pesticide reductions via IPM (157,163), albeit with some successes based primarily on substitutions of materials with toxicity in lower quantities (40,41 nations try to increase agricultural production (31,126,140,166). Grovermann et al (69) estimate that 78% of pesticide use in Thailand is overuse; they attribute overuse to lack of knowledge about nonchemical alternatives, government policies (including tax-exemption and pesticide subsidies), and "lock in" to pesticide use.…”