市场论坛美国蔬菜生产病毒防治及食品安全容易

好像天恢恢 市场论坛--美国蔬菜生产、病毒防治及食品安全

图为美国阿拉斯加大学的教授黄洁华博士

一．美国的蔬菜产业概况1．Large Scale Farming—increase efficiency2．Technology Driven—mechanization, reduce labor cost3．Agribusiness—corporation structure and management for tax advantages, pay self, share holder. Old family farm 20%4．Labor Intensive comparing to other agribusiness5．Good Farming Practice—minimize adversary environment impact

二．传统的蔬菜生产1．Mainstream, capital-intensive 2．Pesticide residue certification—Food and Drug Administration (FDA)3．Require high energy, water and manufacture inputs 4．Permit GM crops and the use of synthetic fertilizers, pesticides and plant growth regulators for promoting plant growth and controlling diseases, insects and weeds5．Higher yield in general, lower yield during drought6．High health risks, pesticide runoff, 7．Accelerate soil erosion8．Nitrite leaching—algal blooms, eutrophication, dead zone

三．有机蔬菜的生产1．Fastest growing sector of the industry: $1 billion in 1994, $13 billion in 20032．Organic Certification—USDA3．Labor and knowledge intensive4．Lower yield in general, higher yield during drought5．Exclusion of synthetic agrichemicals and GM crops.6．Enhance soil health—cornerstone of organic farming7．Use compose, animal manures and fishmeal to maintain soil productivity and promote biodiversity8．Careful crop selection and crop rotation9．Encouraging and introducing beneficial organisms for diseases and insects control. Mechanical cultivation for weed control

四．常见的蔬菜疾病1．Fungal: anthracnose, blight, damping off, downy mildew, early blight, grey mold, late blight, leak, powdery mildew, white mold, wilt2．Bacterial: canker, soft rot, black leg, scab3．Viral: alfalfa mosaic virus, big vein, beet western yellows virus, cucumber mosaic virus, lettuce infectious yellows virus, lettuce mosaic virus, tomato ring spot virus. Vector: aphids, whiteflies4．Phytoplasmal: aster yellows, purple top. Vector: leafhoppers

五．疾病的处理方式1．Certified pathogen-free seed and vegetative propagation materials2．Resistant varieties3．Host eradication, crop rotation, trap plants for vectors, e.g. plant corn, rye among beans, peppers, squash for aphis.4．Post harvest diseases—quick cooling5．Inorganic chemical pesticides—copper, sulfur6．Organic chemical pesticides: fungicides, bacteriocides, insecticides and nematocides (fumigants)7．Strobilurins—the newest fungicides group, interfere with respiration of fungal cell. Site-specific. Effective against most fungal diseases. Disadvantage: affect beneficial microbes 8．Unconventional methods: 1) solarization, 2) film forming compounds (antitranspirant polymers, mineral oils, surfactants) apply to plant surface or water.9．Induce plant disease resistance—salicylic acid

六．通过减少在种植期间病毒的传播，从而有效控制生菜枯萎病(Infectious Yellows Disease)。1．1980’s, Lettuce infectious yellows virus on lettuce reached epidemic proportion in Arizona and resulted in escalation of lettuce price in the US 2．Crop host: lettuce, cucurbits, spinach carrots and cilantro3．Weed host: cheeseweed, dock, wild lettuce, sowthistle, sowbane, sunflowere and Physalis 4．Insect vector of LIYV—sweet potato whitefly, Bemisia tabaci5．Plant hosts of B. tabaci—cotton, lettuce, weeds6．Effective control—reducing population of insect vectors by harvest cotton early or planting lettuce late 7．Current LIYV status: no longer a problem because B. tabaci has all but disappeared.

七．阿拉斯加试验室研发的无疾病土豆种子1．Field disease survey 2．Intensive Plant sampling 3．Lab disease testing of large numbers offungal, bacterial and viral diseases 4．Documentation