UC Delivers

Organic Apple Industry in California

The Issue

In the late 1980's and through most of the 1990's, California had about 15,000 acres in apples and ranked second only to Washington State. Due to strong market competition and low prices since that time, acreage has been on a steady decline--except in organic production.Many California growers wanted to take advantage of higher prices and brisk demand for organically produced apples. Unfortunately, they have had to contend with huge losses from diseases like apple scab and powdery mildew as well as insects such as codling moth and aphids. In years with wet spring rains, apple scab caused a complete loss of blossoms and fruit. In some years, worm-infested apples caused by codling moths resulted in as much as 90% damage in untreated orchards. Aphids and powdery mildew were secondary pests, but under certain conditions could decimate production in orchards where conventional pesticides were not used.

What Has ANR Done?

In 1990, several UC researchers across the state began to study an organic production system model for apples. They concentrated on use of new pheromone confusion technology for codling moth control. They also refined old systems for the use of various minerals, soaps, oils and resistant varieties for control of diseases and aphids that were limiting organic production. Many trials were conducted to evaluate the effectiveness of organically approved calcium materials for the control of bitter pit; for various types of mulches and cultivation to control weeds; for the use of biological control methods; and for meeting the crop's nutritional requirements with compost and cover crops. Scientific research was also conducted for the evaluation of new disease resistant varieties and their economic potential in the organic market. After 10 years of work, the organic apple production system was well documented in the DANR publication # 3403 - Organic Apple Production Manual. Several short courses and field meetings were conducted throughtout the state to present the results of the UC research to growers.

The Payoff

Reliable organic apple production now possible in California

Growers now have a well-documented, successful organic apple production system based primarily on UC's years of research. They can grow apples organically using new disease-resistant varieties with good flavor and a high demand in the market. The organic pest control strategy has eliminated the use of all conventional pesticide materials. The fertility program using compost and cover crops can supply all the needs of an organic apple orchard at a relatively low cost. More growers have been able to remain in business with a specialty organic product during a period of worldwide overproduction of apples. They have been able to switch to an organic system without risking significant crop losses and with only a slightly higher cost of production. Organic apples still receive a premium in the market, with a price that is 2 to 3 time higher than conventional apples.

Contact

Supporting Unit: Sonoma County

Paul Vossen, UCCE, 2604 Ventura Ave., Santa Rosa, CA 95403 (707) 565-2621