Comparative Performance and Farm-Level Function of Conventional and Certified Organic Apple Production Systems in California

1992 Annual Report for AW92-009

Project Type: Research and Education
Funds awarded in 1992: $0.00
Projected End Date: 12/31/1994
Matching Non-Federal Funds: $99,686.00
ACE Funds: $55,224.00
Region: Western
State: California
Principal Investigator:
Dr. Sean Swezey
Center for Agroecology and Sustainable Food System

Comparative Performance and Farm-Level Function of Conventional and Certified Organic Apple Production Systems in California


1. Retain, for multi-year observation, whole systems comparison units of transitional or certified organic and conventional input production as multi-year demonstrations in each of the four important apple production regions in California.
2. Compare potential yield-limiting factors in these systems associated with tree growth and yield, soil characteristics and nutrients, key pests and their associated damage, and natural enemy abundance and response.
3. Demonstrate effectiveness of key management strategies relevant to certified organic production including: codling moth control with pheromone-based mating disruption and microbial sprays; orchard floor management and cover-cropping as a source of soil nutrients and improved structure; and sprayable inorganic or organic compounds and/or cultural substitutions for scab control.
4. Document the economic performance and viability of certified organic production systems or practices in each production region.
5. Disseminate and publish research-based results to the production community, culminating in the publication of the University of California-sponsored “Guide to Certified Organic Apple Production in California.”

Abstract of Results
By the year 2000, California will likely emerge as the second largest apple-producing state in the nation, with a ten percent share of U.S. production and a total harvest of more than 500,000 tons. Apple acreage in California has increased by 50 percent in the past two decades, to nearly 40,000 bearing acres.

Making up a small but growing percentage of statewide production, certified organic apple production represents an emerging technical and marketing alternative for California apples. Certified organic and transitional apple production has expanded to over 3,000 acres in California.

An increasing number of California apple growers recognize economic and environmental incentives of organic apple production, such as price premiums in response to consumer demands, and lessening of regulatory impacts on farm inputs. Many commercial growers could profitably convert to organic production if management knowledge and techniques were available to them in capturing a high-value position in the marketplace.

In 1992 USDA-SARE funded our three-year, farm-based study of the performance of California organic apple production compared with conventional practices. Our research group, comprised of University of California Cooperative Extension farm advisors and research specialists from each of the major valley and coastal production regions, has competed the field research component of this study, and is now writing the “Guide to Organic Apple Production in California” based on these research results.

In 1995, our apple research group completed the third and final production year evaluation of three certified organic/transitional production demonstrations (north Coast, North and South Central Valley, Central Coast). In addition to these long-term demonstrations, the research group also continued and expanded statewide monitoring of synthetic pheromone-based codling moth mating disruption programs, including evaluation of codling moth monitoring and management programs integrating mating disruption with biological (certified organic) and chemical (conventional) controls. Ancillary research included testing of certified organic methods of key disease agent (scab) control, secondary pest (rosy apple aphid) suppression, and post-harvest physiological disorder (bitter pit) prevention.

Codling moth mating disruption with synthetic pheromones, either alone or in combination with biological control agents, sprayed materials, and/or sanitation practices, is highly effective as a certified organic control strategy for codling moth in most California production locations. Disease control with sulfur and copper, when application of these materials is properly timed, provides organic growers with scab control as effective as conventional synthetic fungicides in on-farm tests. Horticultural oils, soaps, and botanical insecticides, were effective tolls for aphids and secondary pests. Unrefined mineral calcium chloride had effects demonstrably equivalent to synthetic calcium compounds in the suppression of bitter pit in stored apples.

Economic Analysis
Certified organic apple production in California has been demonstrated to be commercially profitable under production conditions observed in this study, but is presently a more costly production system in the coastal regions and the northern San Joaquin Valley. Although economic data are difficult to summarize due to difference in varieties, rootstocks, management systems and yearly market prices for organic fruit, farmgate costs of certified organic production exceed those of conventional apples by 10-25 percent in coastal fresh market systems. Farmgate costs ranged from $3300-$4100/acre for production of Central Coast organic Granny Smith apples. Coast of production studies completed in the coastal production areas calculated total operational costs at $4500-$5100/acres (without overhead). Profitability of certified organic apple production systems depends upon micro-climate, root stock/variety combinations, pest and disease pressure, yields, and market prices. Early-maturing varieties (Gravenstein, Golden and Red Delicious) and high-density semi-dwarf root stock plantings of Granny Smith apples and some newer varieties have been successfully converted to certified organic management, and have shown accumulated net profits equal or higher than conventional comparisons over study years in which price premiums were available for certified organic fruit.

Potential Contributions
Final published project results documented the agronomic and economic performance of certified apple production in several California regions. In many cases, yields and quality are maintained in organic production systems by careful application and monitoring of alternative technologies. Research-based guidelines for particular climatic regions are being developed to avoid overgeneralization. Profitable apple production systems which substitute biologically based inputs for synthetically-derived pesticides and fertilizers now serve a growing consumer public in California and national and world markets. Published management guidelines will strengthen grower confidence and lower inherent risks during the process of conversion to these practices in California.

Producer Adoption.
At twenty sites statewide, grower collaborators have adopted some or all of project production guidelines. These “focus” blocks served as the basis for wider dissemination of research-based guidelines for organic production. Project major participants estimate that approximately 350 growers, farm advisors, pest control advisors, and other agricultural professionals have been directly contacted with seminars, presentations, and short course curricula. Major participants held eight extension grower meetings (two each in Watsonville, Santa Rosa, Bakersfield, Modesto; two successive November short course presentations); attendance figures are abed on total participation in these meetings.

Farm/Rancher Comments
“Last year we had severe scab conditions and were able to beat it. That’s a big step forward in saying that the organic deal is viable …[Swezey] got us into the codling moth pheromone program when it was still in the experimental stage, and he was able to really keep track of what was happening during the conversion process.”
--Jim Rider, California Certified Organic Farmers newsletter, Summer 1996.

“It’s a safer product…I think it is a way of the future. We felt comfortable with the program we had last year and decided to increase our acreage.”
--Dago Oseguera, Diablo Green Orchards, Brentwood Reporter, 8-31-96