Effect of seed-borne Mycosphaerella pinodes and seed treatments on emergence, foot rot severity, and yield of field pea

Abstract

Seed-borne Mycosphaerella pinocles in field pea, its transmission to seedlings, and control by seed treatments were studied under growth room and field conditions. Seeds harvested from naturally infected plants were separated into visibly poor (VP) seeds with lesions, and healthy looking (HL) seeds without lesions. In a controlled environment seed-to-seedling transmission was 67-70% for the HL seeds and 94-100% for the VP seeds. Under field conditions, the percentage of seeds infected by M. pinocles was negatively correlated with seedling emergence (r = -0.939 in 1996. P < 0.01, and r = -0.944 in 1997, P < 0.01) and yield (r = -0.929 in 1996, P < 0.01, and r = -0.757 in 1997, P < 0.05), but there was no relationship with the frequency of foot rot symptoms. When seeds were treated with thiram fungicide or ACM94I bioagent (Glioclaclium roseum), both VP and HL seeds showed increased emergence compared with nontreated controls. Thiram was more effective than ACM941 in improving the emergence, however, neither treatment reduced foot rot severity or increased yield significantly in the two years of field tests

Keywords:

• Mycosphaerella pinodes
• field pea
• seed treatment
• Gliocladium roseum