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
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
were infected in the nursery before shipment. Early
detection, quick scouting and tree removal on the part
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.
Photo by Jay Pscheidt,