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Helping farmers find, destroy, and manage EFB


Scouting for early detection is our most important activity for ALL hazelnut growers. Growers from Eugene to Salem must be as vigilant as growers in the greater Portland area. It works! Scout your orchards at least twice a year. 

We recommend that you scout your orchard for EFB at least twice a year. Look for flagging (dying) branches in the summer and characteristic EFB cankers in the winter. Cankers can be found on any part of the tree but are more frequently found near the top. Scout intensively during the winter, particularly on clear days. A pruning tower (tree squirrel) and/or binoculars are very helpful to locate cankers. All orchards in Oregon are at risk and should be scouted, even orchards near Eugene.

There was a situation near Salem where a grower discovered two trees infected with EFB in a newly
planted hazelnut orchard. It was suspected that the trees were infected in the nursery before shipment. Early detection, quick scouting and tree removal on the part of many people helped eradicate EFB from that orchard.

Resistant cultivars planted near heavily infected orchards have developed EFB cankers. Initially, these cankers are characterized by longitudinal cracks, flat and/or slightly sunken areas on the trunks. Some cankers develop stromata which are smaller and less numerous than on susceptible cultivars. After a few growing seasons, cankers on resistant trees may have substantial callus formation indicating a strong wound healing response. Cankers may heal over completely (about a third) while others may only be recognized by superficial cracks, indentations or scar tissue. Unfortunately, a few cankers have developed that look like normal EFB cankers.

When the canker finally girdles a branch the leaves rapidly wilt and die due to lack of water. The brown leaves may remain attached to the branch for some time.
The brown leaves may remain attached to the branch for some time.
Photo by Jay Pscheidt, 1992. 

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Mature, black stromata arranged in rows. Note the sunken area where the stomata are located or the raised area next to the canker. Tree cells in the cankered area are dead and do not continue to grow.
Mature black stromata
Photo by Jeff Stone, 1988.

The image below shows an EFB canker on the cultivar Jefferson. It looks more like a long crack and does not have the characteristic black stroma typical of this disease.
Jefferson Canker 21
Photo by Jay W. Pscheidt, 2012.

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