Campus Units

Plant Pathology and Microbiology

Document Type

Article

Publication Version

Published Version

Publication Date

2-2010

Journal or Book Title

Plant Disease

Volume

94

Issue

2

First Page

167

Last Page

173

DOI

10.1094/PDIS-94-2-0167

Abstract

The relative importance of stem canker of soybean in Iowa compared with other soybean diseases present in the state was assessed using data collected from over 3,400 soybean fields sampled in the Iowa Soybean Disease Survey that was conducted from 2005 to 2007. Symptomatic plant tissues from soybean plants with stem canker symptoms were cultured on acidified potato dextrose agar. The prevalence of stem canker on soybean in 2005 in Iowa was 2.6%; the disease was not detected in 2006 and 2007. In 2005, 63 isolates with Diaporthe/Phomopsis characteristics were collected. To identify isolates to fungal species and variety, single-spored isolates were subjected to polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP) and sequencing of the internal transcribed spacer (ITS) region. Fourteen isolates were identified as D. phaseolorum var. caulivora (northern stem canker) and 49 as Phomopsis longicolla. To quantify and compare the aggressiveness of D. phaseolorum var. caulivora isolates collected in Iowa, nine isolates were arbitrarily selected for components analysis. Incubation period, rate of lesion expansion, final lesion length, and time to plant death for each isolate were quantified. Significant differences in components of aggressiveness were detected among the nine isolates. Results from this work suggest stem canker is a minor disease of soybean in Iowa.

Comments

This article is published as Lu, X., Robertson, A. E., Byamukama, E. Z., and Nutter, F. W., Jr. 2010. Evaluating the importance of stem canker of soybean in Iowa. Plant Dis. 94:167-173. doi: 10.1094/PDIS-94-2-0167. Posted with permission.

Copyright Owner

The American Phytopathological Society

Language

en

File Format

application/pdf

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