Initial Response of Soybean Mosaic Virus, Bean Pod Mottle Viruses and Rotylenchulus Reniformis on Soybean

In recent years soybeans have again become an economical alternative as a rotational crop. Understanding compound stress levels and responses under the presence of reniform nematode (Rotylenchulus reniformis, RR), soybean mosaic virus (SMV), and bean pod mottle virus (BPMV) may give insight into the possibility of overall disease potential. Greenhouse tests were conducted using virus free seedlings of Hartwig and Hutcheson varieties.  Each variety was planted in polystyrene pots containing 500 cm³ of autoclaved soil and inoculated with 1000 vermiform life stages of the reniform nematode. Virus tissue transferred from pure stocks rendered in the greenhouse was applied during the first tri-foliate stage of each test plant. Parameters measured included plant height, reniform reproduction, and Elisa concentrations at 14 and 28 days after inoculation (DAI). Initial testing has shown RR to enhance plant height (28 DAI). Other combinations have shown compounding symptoms, however, both viral pathogens are not always detected during Elisa testing. Hartwig plant height was reduced by both viruses, but the reduction was more severe with SMV.  An estimated 24% reduction by SMV and 28% reduction in combined SMV/BPMV infections were observed. Furthermore, mottling was more severe in the Hartwig variety in both SMV and BPMV treatments. RR did not appear to increase mottling symptoms over the control plants. Mosaic symptoms were significantly more developed in combined treatments of virus and nematode with Hartwig showing greater mosaic symptoms. Treatments containing RR appeared to have higher mosaic percentage when SMV and the combined infections of SMV/BPMV were present.