Organic Vegetable Production in California—Science and Practice

Abstract

<jats:p>This article summarizes the current status of organic vegetable production practices in California. The production of vegetables organically is growing rapidly in California, led in large part by growth in the market demand for organically grown produce. Key aspects of organic vegetable production operations such as certification and farm production planning, soil management, weed management, insect management, and plant disease management involve special practices. Many practices have not been thoroughly researched and the scientific base for some practices is still being developed.</jats:p>

Transition from Conventional to Organic Farming Systems: I. Challenges, Recommendations, and Guidelines for Pest Management

“…Also, Gaskell (1999) showed that feather meal performed the best among seven tested organic fertilizers on bell pepper (Capsicum annuum). Materials such as gypsum, lime, or potassium magnesium sulfate can be used to correct deficiencies or imbalances, raise soil pH, leach out excess exchangeable sodium via Ca replacement, and/ or improve soil water infiltration (Gaskell et al, 2000).…”

“…WEED MANAGEMENT. During and after transition periods, the weed seed bank may be reduced through cultivation, chipping and hand-weeding, in-terrow cultivation, straw mulch, palletized paper-waste mulch, flame weeding and the use of weed mats (Kristiansen, 2000), crop competition, and cover crop residues (Teasdale, 1993), water management, solarization, and chemical controls such as acetic acid, corn gluten, and citric acid (Fernandez-Cornejo et al, 1998;Gaskell et al, 2000). Other methods useful for all crops and essential for long-term weed management include a program of crop rotations, including green manure crops between cash crops, preplanting cultivation, slashing/mowing to avoid seeding, maintaining good farm hygiene, and avoiding procrastination (Fernandez-Cornejo et al, 1998).…”

“…Monitoring for insects and proper identification of immature life stages of an insect will greatly aid in preventing economic damage to crops. When pest populations get out of balance, growers may implement a variety of strategies including 1) insect predators such as ladybugs (Coccinellidae), lacewings (Neuroptera), syrphid flies (Syrphidae), or parasitic wasps (Hymenoptera) to control aphids (Aphididae) and other pest populations (Corbett and Rosenheim, 1996;Gaskell et al, 2000;Yespen, 1976), 2) mating disruption through pheromones (Wang et al, 1997), and 3) traps and barriers (Yepsen, 1976).…”

“…Insects are less likely to develop resistance to soaps and oils. These chemicals control insects by physical actions such as suffocating or dislodging insects from the crop (Gaskell et al, 2000).…”

“…Growers must be careful when selecting sites for organic farming, especially sites that have histories of soilborne pathogens such as Fusarium, Phytophthora, Pythium, and Rhizoctonia. However, this strategy may be less helpful in California, where these pathogens are widespread and the use of resistant cultivars or plant stocks would be a better practice (Gaskell et al, 2000).…”