Jay W. Pscheidt, Extension Plant Pathologist
set of management recommendations may seem daunting at
first. Some of you may not have enough resources (time
and/or money) to fully implement the whole program on all
of your acreage. It is often asked how best to deploy
limited resources against this disease in heavily
infected orchards. Not an easy task since everyone has a
different situation and not implementing all of the
management tactics is risky.
Given limited resources you have several choices: 1)
You could pretend the disease was not in your orchard and
do nothing, 2) you could do a portion of the controls on
all of your acreage or 3) you could do all of the
controls on a portion of your acreage.
The practice of doing nothing will never be
recommended. The data are clear, the disease will spread
quickly and significantly reduce yields.
Most growers try a little something on most of their
acreage. We have very little data with which to guide you
in this area. We know that practices such as only
cultural controls in the absence of chemical controls
will not control EFB. We also know that the single
fungicide spray per year approach will not work either.
In any one year, a single spray at budbreak has a 60%
probability of achieving EFB control.
However, over multiple years, there will be a 100%
failure of control.
So how about implementing all of the control
recommendations on a portion of your acreage? Ok, but
what portion? In general, many growers may be overly
focused on the diseased part of their orchard.
Growers should focus their energy and resources on the
healthy part of the orchard each year. All of the disease
management tactics are geared toward protecting or
reducing the EFB risk of healthy trees. The act of
removing cankered wood from an infected tree is as much
an act of reducing the spore load in your orchard as it
is to eradicate EFB from the tree. Time spent scouting
for EFB is best done in the healthy orchard since that
one canker can become hundreds if not found early.
Although scouting for cankers in the infected orchard is
easier, you already know it is there! The fungicides can
only protect healthy shoots and trees. They can not
remove cankers from infected trees.
the healthy portion is protected but what do you do with
the diseased portion of the orchard? This will depend on
what resources you have left. How many cuts can you
afford ($) per tree? One? Two? Not much of a tree is left
but it may be the right decision. What about fungicides?
Some of you get a better price on copper products but
realize it is not as effective as Bravo. You might
consider using Bravo on the healthy part of the orchard
and copper products on the diseased portion.
The first choice would be to implement the full set of
recommendations on all of your acreage. We know that
growers who have done this for many years have been able
to maintain yields as if there were no disease. Doing
nothing is unacceptable especially from an area
perspective as it increases the whole industry's risk to
EFB. Orchard inputs increase when managing EFB. It is
difficult to justify these inputs especially when nut
prices are low. Smaller acreage may be necessary to
adequately control EFB given the same amount of
Everyone knows the Hollywood mythology that werewolves
can only be killed by a silver bullet. We sometimes
extend the analogy to plant diseases such as EFB where we
hope a single application of something (the silver
bullet) will completely control the disease. Like the
werewolf, such hopes are probably mythical. Management of
EFB will require hard decisions and a lot more work. It
is often said that EFB takes the FUN out of filbert
This does not mean that the future is not bright.
Indeed, new chemical registrations along with new
resistant or immune cultivars will be available soon. Nut
prices have rebounded from a low several years ago. There
is good reason to believe that the next generation will
still be growing hazelnuts, profitably, despite the