Participatory Research for the Dynamic California Strawberry Industry

Carolee T. Bull

Strawberries are one of the most important crops in California, ranking 11th in importance, with production figures reaching $686 million dollars annually. California supplies 12% of US fresh and frozen strawberries to export markets. In 1998, 70,566 and 354,486 lbs. of strawberries were produced for fresh and frozen markets respectively on approximately 23,000 acres.

California strawberry producers can attribute their high yields and crop values to the use of a highly perfected annual production system. The production system relies on certified transplants, sophisticated soil preparation, intensive hand labor, a specialized fertilization regime, and intensive management of foliar diseases and insect pests. Preplant fumigation is an important tool in guaranteeing high strawberry yields in fruiting fields and disease-free transplants from nursery fields. Fumigation with a 2:1 mixture of methyl bromide and chloropicrin is a standard practice throughout the California strawberry industry for controlling plant pathogens, nematodes, and weeds. Consecutive years of strawberry production on a given piece of land and on marginal land are successful because of fumigation. Diseases and weeds controlled by fumigation, and insect pests are the most important biological challenges to strawberry production.

High production and harvesting costs make strawberry production a capital-intensive proposition. Growers can invest $25-37,000 per acre to produce and harvest their crop. In the recent past, the high cost of production has prohibited growers from experimenting with biologically based alternatives to their current management regime. However, methyl bromide is a class I ozone depleter, and as such is scheduled for a 100% use reduction by 2005 through the Montreal Protocol. In addition, use of both methyl bromide and chloropicrin is under review by the US-EPA as part of the Food Quality Protection Act (FQPA) of 1996. In addition to chemical fumigants, other chemicals important for insect and disease control are being reviewed by the EPA as part of the FQPA. Current yields, profits, and the durability of some farms are being threatened by the advent of the loss of these chemical tools. The timbre of the discussion of research objectives within the industry has changed and alternative cropping systems are now of interest. Research which targets reduction or one-for-one replacement of chemicals can cause unintended problems in other aspects of the management system. By using a BIFS research model, multiple groups are working together to solve aggregated problems simultaneously.

In 1999 the BASIS (Biological Agricultural Systems In Strawberry) and OASIS (Organic Agricultural Systems In Strawberry) management team was formed. The goal of the BASIS program is to develop an economically strong integrated management system for strawberries that addresses the multiple challenges facing the industry. The goal of the OASIS program is to improve organic production systems. The number of growers producing certified organic strawberries is increasing steadily: in the last five years, the number of strawberry growers certified by CCOF (California Certified Organic Farmers, the most common California organic certification agency) grew from 18 to 29 (CCOF 1993, 1998), with a similar increase in total acreage. However, until recently little research has been done to assist these growers in developing optimal organic strawberry production methodologies. Initially the management team developed a template for both the conventional and organic production systems. Our research is continuing to refine the template based on experiments that are being carried out on BASIS or OASIS growers’ fields.

For the 1999-2000 farming season there are 13 farmers enrolled in either the BASIS or the OASIS programs. Six of the farmers use organic farming practices and 7 use conventional practices. Three of the conventional farmers are beginning organic blocks in part due to their work with the BASIS program. A total of 29 acres are enrolled in the program. This is an increase of greater than 50% over the first year of the program. Growers have either demonstration or experimental plots. 5.5 acres are in demonstration plots, with the remaining acreage is dedicated to research.

Currently, the prescribed soil treatments include the use of an activated compost, biological control using bacterial agents, and a mycorrhizal inoculant. Some growers are adding to these treatments alternative mulches, solarization, crop rotation, and cover crops as they fit their needs. Microbial agents, sanitation, and compounds that stimulate plant defenses are being used for control of foliar and fruit diseases. Intensively managed trap crops and farmscaping are the two insect management activities being evaluated by the growers.

Carolee T. Bull, Research Plant Pathologist
USDA/ARS
1636 E. Alisal St.
Salinas, CA 93905-3018
Tel: (831) 755-2889
CTBull@aol.com

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