P-155 - Solarization used as an organic control for nematodes and soilborne bacterial soft rot pathogens of onion in Texas

Burkholderia gladioli, causes “sour skin" in onions and is part of a broader group of bacterial soft rot diseases. In organic onion production, solarization has been proposed as a control method for this disease, as well as for soilborne nematodes. The objective of this study was to evaluate the effectiveness of soil solarization of soil in raised beds, under central Texas environmental conditions. Infested onion tissue in mesh bags (for ease of recovery) were buried at different depths in October and evaluated over a period of six weeks by plating recovered tissue on a selective medium.  There were no plant parasitic nematodes in the soil, so only free-living nematode populations were assessed, using the pie pan extraction method. There was a significant reduction in both nematode species and populations 13 weeks after treatment.  B. gladioli persisted in untreated soil for up to 10 weeks, but survival decreased in solarized soils. Larger-scale field experiments are underway to confirm the effectiveness of solarization in controlling both the bacterial pathogen and nematodes.