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Southeastern Apple ProductionPLANT PATHOLOGY |
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Nectria Twig Blight
Nectria cinnabarina
Nectria twig blight, caused by Nectria cinnabarina, is occasionally a problem on strains of Rome in the southeastern United States. Nectria gallegnia causes a canker but is rarely observed in the Southeast.
Symptoms
Symptoms somewhat resemble fire blight and are often confused with it. Infections originate in fruit pedicel scars or broken pedicels on last year's cluster bases and result in cankers, which girdle the stem and cause the affected shoot to die. Cankers are orange-brown. Leaves often remain attached to dead shoots.
Nectria cankers
Disease Cycle
The fungus survives in small cankers in the tree. New infections arise on pedicle scars or broken pedicles during the fall and spring, following dispersal of spores by rainfall to these sites.
Control
There are no effective chemical controls. Infected shoots should be cut out to reduce the inoculum and to remove dead wood that can be a host for summer rot fungi.
Recommendations for the use of agricultural chemicals are included in this publication as a convenience to the reader. The use of brand names and any mention or listing of commercial products or services in this publication does not imply endorsement by North Carolina Cooperative Extension nor discrimination against similar products or services not mentioned. Individuals who use agricultural chemicals are responsible for ensuring that the intended use complies with current regulations and conforms to the product label. Be sure to obtain current information about usage regulations and examine a current product label before applying any chemical. For assistance, contact your county Cooperative Extension agent. |
Department of Plant Pathology
North Carolina State University
Raleigh, NC 27695 USA
Web Crafters: Anne S. Napier and
Steve Schoof |
Format updated March 29, 2011