Submitted to: Plant Health Progress
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/16/2015
Publication Date: 4/15/2015
Citation: Mathew, F.M., Castlebury, L.A., Taylor, C.A., Jordahl, J.G., Meyer, S.M., Lamppa, R.M., Pasche, J.A., Markell, S.G. 2015. Identification of Diaporthe longicolla on dry edible peas (Pisum sativum), dry edible beans (Phaseolus vulgaris) and soybeans (Glycine max) in North Dakota. Plant Health Progress. DOI: 10.1094/PHP-RV-0045. Interpretive Summary: Phomopsis seed decay and stem disease of soybean caused by Diaporthe longicolla are economically important diseases in some U.S. states. Some species of Diaporthe are able to infect and cause disease in more than one crop plant. In North Dakota, soybeans (Glycine max) are planted in the same areas as dry edible beans (Phaseolus vulgaris) and dry edible peas (Pisum sativum) and often included in crop rotation systems including these crops. In 2009 and 2010, diseased stems were observed in all three crop plants in North Dakota. To determine if Diaporthe longicolla was causing this disease, fungal cultures were isolated from diseased stems of beans, peas and soybeans. Using DNA sequences and spore characteristics, we identified the causal agent of the stem disease as Diaporthe longicolla. This was the first report of this fungus causing a stem disease on dry edible beans and peas anywhere and the first report on soybeans in North Dakota. This research will be used by extension agents, plant breeders, and plant pathologists to implement management strategies for stem diseases of these three crop plants.
Technical Abstract: Diaporthe longicolla is a fungal pathogen that causes Phomopsis seed decay and stem disease of soybean, economically important diseases in some U.S. states. Dry edible bean, dry edible pea and soybean stems with unidentified lesions were collected from fields in North Dakota. Diaporthe longicolla was determined to be the causal agent on all samples. This is the first report of D. longicolla in North Dakota on any crop, and to the best of our knowledge, is the first report of D. longicolla on dry edible peas and dry edible beans. The production areas of dry edible beans, dry edible peas and soybeans overlap in North Dakota, and the identification of D. longicolla on all three crops may impact disease management practices in North Dakota, particularly crop rotation.