eastern filbert blight gets into a hazelnut tree it can only
be removed by pruning off the infected portions. Pruning out cankers
before budbreak in the spring (early March) also reduces the chance of
more infections on healthy trees. Simply cutting down cankers or heavily
infected trees is not enough to reduce the threat of EFB. Spores of this
fungus can still be produced from cankers sitting in brush piles next to
or within orchards. The cankered wood must be destroyed to kill the fungus
and reduce your EFB risk. Burning your prunings on site is one way to
destroy the infected wood.
For most of us, we only need to worry about general
agricultural burning between October 15 and June 15. Most of our pruning
will be done during the winter months and must be destroyed before
budbreak in the spring. Fire safety and air quality are the two important
factors with regard to burning that are regulated in Oregon. Although it
may seem like there are many regulations and that you might get a "run
around' when making inquires, in general, there are few restrictions for
agricultural burning (as long as it is not grass seed or gain fields).
Before you burn you need to contact your local fire
district about fire safety. In general, you will get a "verbal" burn
permit but there may be other regulations depending on your local area. At
the very least, they like to know who will be burning and when in case
they get any calls about the fire. The following web site has links to
many fire districts. They may or may not have information on open burning
but remember "agricultural burning" is not subject to local open burn
Oregon Fire Department Links -
Also find out if the day you want to burn is a "burn day".
There is a
phone number to call or a web site you can look at to get this
information. The "grower line" is 503-986-4755 and will let you know about
the restrictions for that day. Burn advisories can be obtained at the
following web site for various areas of the state. You can even sign up
for an e-mail subscription. Remember that you can only burn during
Burn Advisory - http://www.deq.state.or.us/aq/burning/
If all else fails, give John Byers a call at 503-986-4718. He
Management Program Coordinator & Public Information and Outreach
Specialist for ODA. He is very helpful and knowledgeable about these
Growers are concerned about restrictive regulations for burning EFB infected branches. They would like to chip
infected branches but leave the biomass spread throughout the orchard.
We have found that canker pieces with intact stroma do survive the chipping process and produce spores when wetted.
Studies were conducted in 2006
and again in 2012-2014
to evaluate the risk of
Spore counts above piles of chipped brush were lower than above intact brush piles with EFB.
In 2006, healthy 2 yr-old Ennis trees were planted into and outside of an area with chipped brush. The incidence of
infection did not significantly increase when trees were located within or next to the chipped brush. Similar potted
trees were placed within and downwind of chipped brush in both 2012 and 2013. Again, in both years, there was little to
no infection of these trees. (In contrast, potted trees were not only infected when placed within intact brush piles but
also 60 feet down wind! (Heckert et al 2014)).
Coarse chipping hazelnut branches with eastern filbert blight EFB cankers appears to reduce the overall risk of
disease development. Although viable ascospores can be detected within and above piles of chipped EFB cankers, there are
not enough to consistently infect susceptible trees within or downwind of these piles. Growers are advised to grind
branches into as small a particle size as possible to break up EFB cankers, encourage decomposition of chips and to limit
possible interference with mechanical harvest in the fall. Because whole branches can still pose a threat to disease
development, cankered branches need to be ground up prior to bud break in the spring.