488 Effect of Oat Extract on Pea Root Rot Pathogen Aphanomyces euteiches

Abstract

Pea root rot is a serious economic threat to pea production in the Great Lakes region. The primary causal organism is Aphanomyces euteiches Drechs., which is responsible for an estimated 10% annual crop loss. A fall oat (Avena sativa) rotation before spring pea planting reduces disease severity. To better understand the beneficial effect of oat on A. euteiches, isolated individual pathogen lifecycle stages of zoospores, mycelium, and oospores were treated in culture with oat extract. Resulting mycelial mats were dried and weighed. Treatment with 90%, 70%, 50%, and 30% oat extract resulted in significant spore germination and mycelial growth of A. euteiches. In the presence of nutrient solution, oat extract concentrations of 90%, 70%, 50%, and 30% significantly enhanced spore germination and mycelial growth of the pathogen. These results demonstrate that the use of oat extract results in dosage dependent germination and growth of A. euteiches.