- Vegetables: tomatoes
- Pest Management: biological control, integrated pest management
- Soil Management: soil microbiology
Studies on anaerobic soil disinfestation (ASD), a non-chemical alternative to soil fumigants for controlling many soilborne diseases, have shown that it enhances populations of beneficial microorganisms against plant pathogens, including increased presence of the biocontrol agents Trichoderma and actinomycetes as sclerotial parasites of Sclerotium rolfsii. However, studies on ASD effectiveness paired with beneficial microbes application are lacking. The proposed study will isolate two biocontrol agents from ASD-treated soils, Trichoderma and actinomycetes, and compare the effect of inoculation of these organisms at the initiation of ASD treatment separately and in combination on treatment effectiveness against the S. rolfsii pathogen. The study will be performed in pots with treatments factorially combined with two C rates (2 and 4 mg C/g of soil) and arranged in a completely randomized design in an environmentally-controlled growth chamber. As there is increasing need to optimize rates of C in soil amendments for effective ASD treatment, we will also analyze the effect of ASD C amendment rates on populations of biocontrol agents. While there is some research on effect of ASD on bacterial communities, studies on ASD impact on beneficial fungal populations are lacking. Hence, with the application of molecular techniques, the 16S-23S (bacterial) or 18S (fungal) ribosomal DNA will be amplified and sequenced for phylogenetic analysis of Trichoderma , actinomycetes and Bacillus populations. If successful, our results will contribute to the development of more effective ASD treatment methods for control of soilborne plant pathogens for vegetable and small fruit growers in the southeast.
Project objectives from proposal:
1. Determine the impact of Trichoderma and actinomycetes against sclerotia of S. rolfsii in ASD with different C rates at ranges of C:N ratios
2. Evaluate the effect of ASD amendment carbon sources on populations of Trichoderma, actinomycetes and Bacillus