Source and spread of peanut mottle virus in soybean and peanut

Virus incidence and distribution data show that the source of groundnut mottle virus for soybean is infected groundnut. The source of virus in groundnut is infected seed [RPP 53, 3706]. The virus is transmitted from groundnut to soybean, from soybean to soybean, and from soybean to groundnut. It can move at least 48 m in a single step to previously uninfected plants but apparently not 6.5 km. As the distance between inoculum source and adjacent plantings increases, the time until initial infection increases, resulting in a lower percentage of disease at crop maturity. The rapid increase of this disease in a planting was the result of inoculum dissemination from within, as opposed to between, plantings. It is this internal spread that leads to epiphytotic conditions.