Browse on keywords: disease WA biological control
Search results on 09/25/18
10606. Wohld, M.. 1991. Pest control with green manure crops.. Washington Farmer Stockman, March 1991, p. 20.
Natural fumigation by rapeseed and sudan grass has shown promise in controlling diseases, nematodes, and weeds at Prosser, WA. The decomposign residues release compounds toxic to various pests.
10516. Short, R.. 1991. Common root rot of peas incited by Aphanomyces euteiches.. handout at Crops 510 seminar, WSU.
Aphanomyces euteiches is often the primary and dominant invading species of a pathogen complex that attacks peas, along with Fusarium, Pythium, Rhizoctonia, and Ascochyta. Aphanomyces causes 16-20 million dollars of crop loss annually in the U.S. The oospores may persist in soil for more than 20 years, making it a difficult disease to eliminate. Control of Aphanomyces demands and integrated approach due to its invasive and pervasive nature. Field sampling can help determine inoculum levels, and crop sequences can be altered. In some cases, a break of five or more years between pea crops is needed to lower inoculum levels for minimal damage. Cultural practices which reduce soil compaction and promote drainage are beneficial. Organic amendments such as crucifer green manure crops have reduced inoculum levels in infested soils. Biological control agents, such as Trichoderma and Pseudomonas, show promise. Breeding for multiple disease resistance is another important strategy.
11085. Cook, R.J. and A.D. Rovira. 1976. The role of bacteria in the biological control of Gaeumannomyces graminis by suppresive soils.. Soil Biol. Biochem. 8:269-273.
The suppresion of take-all by certain soils or following certain soil treatments is considered to be an expression of either specific or general antagonism. Specific antagonism is effective in dilutions as high a 1 in 1000, can be transferred from soil to soil, operates near or on wheat roots, is destroyed by 60 C moist heat, is fostered by wheat monoculture, but may be lost by fallow or rotation with certain crops, especially legume hay or pasture. Strains of Pseudomonas fluorescens may be involved. General antagonism is a soil property which cannot be transferred and is resistant to 80 C heat, to chemical fumigation, but not to autoclaving. Take-all control by organic amendments, minimum tillage, or a soil temperature of 28 C may be expressions of increased general antagonism. In southern Australia, take-all losses can be very heavy. Some general antagonism occurs, but seldom any specific antagonism. Both types occur in dryland wheat areas of the Pacific Northwest, where take-all is virtually non-existent.