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United States Department of Agriculture

Agricultural Research Service

Research Project: ECOLOGICALLY-SOUND PEST, WATER AND SOIL MANAGEMENT STRATEGIES FOR NORTHERN GREAT PLAINS CROPPING SYSTEMS

Location: Agricultural Systems Research Unit

Title: Impact of interaction of Cercospora beticola and Pyrenophora teres on their potential for survival

Authors
item Lartey, Robert
item Caesar, Thecan
item Salami, Abiodun -
item Hanson, Sophia
item Balogh, Erika -
item Ghoshroy, Soumitra -

Submitted to: International Congress of Plant Pathology Abstracts and Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: May 30, 2013
Publication Date: N/A

Interpretive Summary: In the Northern Great Plains (NGP) of the US, sugar beet and barley are two major crops which are commonly rotated. Cercospora leaf spot (CLS) caused by Cercospora beticola and net blotch caused by Pyrenophora teres, major foliar diseases of sugar beet and barley respectively also occur very frequently in the region. The rotation of the two crops is highly recommended to reduce inoculum and manage both diseases as both pathogens survive in infested host tissues in the soil. We studied interaction of C. beticola and P. teres and the impact of each pathogen the other’s potential survival. Primary experiment was carried out in petri dish in which, growth of C. beticola was significantly inhibited when it was paired against P. teres under dark conditions. However under light, P. teres failed to establish contact with C. beticola. In a follow up microscopic examination, cercosporin was observed in Cercospora hyphal strands prior to contacts with P. teres. Hyphal strands of both fungi were without noticeable damage when observed from contact under darkness. However when observed on contact under light, major hyphal damages were observed on P. teres indicating C. beticola induced structural damage of P. teres hyphal cells prior to actual physical contact. These observations indicate that the two pathogens were able to successfully antagonize each other under certain condition. P. teres is able to antagonize C. beticola under darkness, while C. beticola successfully antagonize P. teres under light. Our results suggest that potential manipulation of abiotic condition may lead to successful management of primary inoculum of both pathogens.

Technical Abstract: Sugar beet and barley are two commonly rotated major crops in the Northern Great Plains (NGP) of the US. Cercospora leaf spot (CLS) caused by Cercospora beticola and net blotch caused by Pyrenophora teres are major foliar diseases of sugar beet and barley, respectively, and also occur very frequently in the region. Both disease pathogens survive in infested host tissues in the soil. Rotation is highly recommended to manage both diseases by reducing inoculum potential. Experiments were conducted to study interaction of the two pathogens and their potential impact on each other’s survival. In petri dish experiments, growth of C. beticola was significantly inhibited when it was paired against isolate of P. teres under dark conditions. However, P. teres failed to establish contact with C. beticola when the cultures were exposed to light. Microscopic investigation has revealed cercosporin in Cercospora hyphal strands prior to contacts. Hyphal strands of both fungi were without noticeable damage under darkness. However under light, significant hyphal damages were observed on P. teres indicating C. beticola -induced structural damage of P. teres hyphal cells prior to actual physical contact. These observations indicate that the two pathogens were able to successfully antagonize each other under specific abiotic condition (P. teres under darkness and C. beticola under light). Our results suggest that potential manipulation of abiotic condition may lead to successful management of primary inoculum of both pathogens.

Last Modified: 4/20/2014
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