Organic wastes create environmental problems and often require landfill disposal. Research at Oregon Soil Corporation and their academic partners at the Ohio State University has shown that organic wastes can be broken down into valuable soil amendments or plant growth media, called vermicomposts, by earthworms using a range of technologies. Vermicomposts have dramatic effects on rates of plant germination, growth, flowering and fruiting. Recent research at OSU has indicated that vermicomposts can suppress the incidence of arthropod pests, plant diseases and plant parasitic nematodes, and that weed seeds and human pathogens are eliminated during vermicomposting. The objectives are: To assess the degree and extent of suppression of plant diseases, plant parasitic nematode populations and arthropod pest numbers, on horticultural crops, by vermicomposts in the laboratory and greenhouse. To assess the degree and extent of suppression of plant diseases, plant parasitic nematode populations, and arthropod pest numbers, on horticultural crops, by vermicomposts in the field. To determine the fate of weed seeds in food wastes and biosolids during vermicomposting. To assess the degree and timing of suppression of human pathogens in food wastes and biosolids during vermicomposting. If wide-spread and significant suppression of plant pests and diseases by vermicomposts and reductions of human pathogens and weed seeds can be achieved by vermicomposting, this would provide a major boost to marketing vermicomposts and ensure their general public and horticultural acceptance. OBJECTIVES: The efficient production of high value horticultural vermicomposts, using automated high technology continuous-flow reactors and, their beneficial use in greenhouse and field applications have been demonstrated convincingly by Oregon Soil Corporation and at OSU with positive results, with previous USDA Phase I and Phase II support. For extended successful commercial development of vermicomposts, further critical research questions relating to the effects of vermicomposting food wastes and biosolids on plant pests and human pathogens still remain to be answered. These include: Objective 1: The degree and extent of the suppression of plant diseases, plant parasitic nematode populations and arthropod pests numbers on horticultural crops, by vermicomposts, in the laboratory and greenhouse Hypothesis: Low application rates of vermicomposts (10%-30%), substituted into a soiless horticultural growth medium (MetroMix360), will produce significant reductions in the attacks by plant pathogens, plant parasitic nematodes, and insect and mite pests on tomatoes and pumpkins, in the greenhouse. Objective 2: To assess the degree and extent of the suppression of plant diseases, plant parasitic nematode populations and arthropod pests numbers on horticultural crops, by vermicomposts in the field Hypothesis: Low and economically-viable field application rates of vermicomposts (1-2.5 tons/ha-1) will decrease attacks by some plant pathogens, plant parasitic nematodes, and insect and mite pests significantly. Objective 3: To determine the fate of weed seeds in food wastes and biosolids during vermicomposting Hypothesis: Most viable weed seeds will be destroyed or germinate and be killed during vermicomposting. Objective 4: To assess the degree and timing of suppression of human pathogens in food wastes and biosolids during vermicomposting. Hypothesis: The important human pathogens Escherichia coli, Salmonella sp., enteric viruses, and helminth ova will be reduced below Class A limits in soil additives after 50-70 days vermicomposting of food wastes and biosolids APPROACH: The research in this Phase II Work Plan, will assess the effects of vermicomposts on the incidence of plant parasitic nematodes, arthropod pests and diseases, and the reduction of viable weed seeds and human pathogens during vermicomposting. The research will be mainly at the production site of Oregon Soil Corporation, which has two vermicomposting reactors and about 20 acres of land available for field trials. The food waste and biosolids vermicomposts for all experiments will be processed in continuous flow reactors at Oregon Soil Corporation. The Corporation also has two small glass greenhouses, to house some of the greenhouse experiments, which will compare the incidence of a range of arthropod pests, plant diseases and plant parasitic nematodes on key vegetable and ornamental crops grown with vermicompost additions, compared with that in the same crops grown with inorganic fertilizers or traditional composts. Some of the laboratory and greenhouse-based plant pathogen, plant parasitic nematode, and arthropod pest research will be subcontracted to Dr. Clive Edwards at the Ohio State University. Some field trials will be at the Oregon Soil Corporation and some at the Ohio State University. Dr. Edwards and his staff will provide supporting data on plant and human disease suppression in the laboratory and field, pathogen, nematode and insect identifications, laboratory weed seed suppression experiments and a range of chemical, physical and biological analyses of vermicomposts, soils and plants, associated with the field and greenhouse trials. The project will focus on the vegetables, tomatoes, peppers and pumpkins, as key test plants in both greenhouse and field experiments. However, we will also compare on the effects of vermicomposts, with those of inorganic fertilizers, on the incidence of plant diseases, plant parasitic nematode populations and arthropod pests, in field experiments on strawberries and grapes, and the ornamentals, petunias and marigolds. These experiments will assess the effects of food waste and biosolids vermicomposts on populations of all pest and diseases, occurring naturally on these crops. In the field experiments, indigenous arthropod pests such as flea beetles and leafhoppers, will be monitored on pumpkins; and cutworms, other caterpillars, flea beetles, other hornworms, corn earworm, whitefly, and leaf miners will be monitored on tomatoes and peppers. The research on suppression of weed seeds during vermicomposting will be in mini-reactors at Oregon Soil Corporation and in laboratory experiments at OSU. The research on the suppression of human pathogens during vermicomposting will use both the full-scale continuous flow vermicomposting reactors, and commercially-available mini-reactors (about 1 m2), designed by Dr. Clive Edwards, at the Oregon Soil Corporation, as well as involving further laboratory experiments at OSU. The human pathogen analyses in the parent wastes and vermicomposts will be done by a commercial laboratory. The whole research program will be under the overall supervision of the Principal Investigator, with the support and advice of Dr. Clive Edwards, as a consultant on the project
