|Wang, L - Washington State University|
Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 4/15/2017
Publication Date: 12/1/2017
Citation: Wang, L., Mazzola, M. 2017. Factors affecting emission of AITC and subsequent disease control efficacy of Brassica juncea seed meal soil amendment. Phytopathology. 107(Suppl.5), 46.
Technical Abstract: Soil physical conditions demonstrably affected allyl isothiocyanate (AITC) emitted from Brassica juncea cv Pacific Gold seed meal (SM) amended soil. The AITC concentration detected increased with an increase in temperature from 10 oC to 30 oC. AITC concentration also increased with an increase in soil moisture, however a significant decrease in AITC generation was observed under the extreme moisture conditions of dry ('T below -1000 kPa) and soil saturation. At the same moisture and temperature condition, AITC emission was not significantly affected by soil texture. AITC insensitive fungi Trichoderma spp. and Mortierella spp. were not suppressed in SM treated soil regardless of the soil physical conditions. Incubated for 24 hr in SM treated soil, the AITC sensitive pathogens Pythium ultimum and Rhizoctonia solani AG-5 were effectively controlled when a peak AITC concentration above 0.01µg/ml was attained. In orchard study, Pratylenchus penetrans root densities were significantly reduced in SM treated soil relative to control and fumigated soil even at 5 months after tree planting. Total fungal density in SM treated soil was significantly higher than control and fumigated soil. In addition, microbial community composition in the rhizosphere of trees planted in SM treated soil was significantly different from the control soil, suggesting that long term pathogen suppression may function through the soil microbiome.