Jay W. Pscheidt, Extension Plant Pathologist
Orbit / Tilt
Abound is registered for hazelnuts and
is a group 11 fungicide also known as a strobilurin. These
translaminar properties meaning that they move into the
plant tissue but do not move with the transpiration
stream. Abound is best used as a protectant
material similar to way Bravo is used. Unlike Bravo,
Abound should be used at 10 day intervals. Greenhouse trials
have shown that this product does not have after infection
Rates should be kept high at 12 fl oz/A as stated on the
label. We obtained 96% control during
the spring of 1998 using Abound at 15.4 fl oz/100 gal
water. However, control has averaged only 62% when rates were
dropped to 3 fl oz/100 gal water.
Adament is a prepackaged mix of Elite
(tebuconazole, group 3) and Gem (trifloxystrobin, group 11). Both
products have worked well alone in the past. Testing of rates below 3 fl
oz/100 gal water were always significant but averaged only 64% control.
Testing at 3 fl oz/100 gal water gave 38% control but then all materials
with either chemistry did not do well that year. The 3 fl oz/100 gal
water rate plus the surfactant Silwet did well the next year with 89%
control. Registered rates for Adament 50 WG are at 4 to 8 oz/A (plus a
surfactant). The only problem with using combination materials is that
you must switch to a different chemistry after 2 applications. The only
other chemistry to alternate with would be materials that contain
chlorothalonil such as Bravo.
Bordeaux is a mixture of copper sulfate plus
hydrated lime. It is recommended to use as a 6-6-100
which means 6 lb copper sulfate plus 6 lb hydrated lime
per 100 gallons of water. Bordeaux mixture's ability to
weather spring rains and adhere to plants is a valuable
characteristic. However, if not mixed properly it has the
tendency to clog sprayer lines and nozzles. It must be
made just before spraying as in will loose efficacy when
left in the sprayer for extended periods of time. It also
has the tendency to burn young hazelnut foliage.
Most of the EFB control information on Bordeaux comes
from Dr. Ron Cameron's work with mature, infected trees
prior to the 1990's.
At that time they were not aware that ascospores of
the fungus infected through young developing shoots. The
average number of applications was 2.7 but only an
average of 1.5 applications were applied during the
spring to protect young shoots. Out of 6 trials, the
average level of EFB control was 71%.
Most all of the other data in this report was
conducted since 1989 using young, healthy trees.
These healthy trees were inter-planted within heavily
diseased orchards during the dormant season, sprayed with
fungicide during the spring growth period, then tended
until the following year when they were evaluated for EFB
cankers. These trees were never used again for testing as
a new set of trees was used each year. Using this
technique there has only been one field evaluation of
bordeaux, applied 4 times for an average level of 74%
(chlorothalonil) and generics such as Echo
Bravo (chlorothalonil) is an excellent,
broad-spectrum fungicide registered on a wide variety of
crops. It is one of the longest residual fungicides on
the market today. Another useful characteristic is
redistribution during rain events. A small but important
portion of each application redistributes to other
possibly unprotected parts of the plant during
rainstorms. After approximately two weeks, depending on
weather events, much of the material is washed off and
reapplication is necessary for continued protection. Soil
microorganisms quickly decompose any material washed onto
the ground. Some people develop an allergic skin rash
upon repeated exposure to this chemical.
Bravo was one of the first fungicides we found to be
highly effective against EFB. I can still remember
walking through a trial in 1989 that everyone thought was
a failure. Many fungicides had been applied to several
replicate trees but primarily during the dormant
A lot of disease developed in the trees, which is why
no one thought much of it. I walked to each replicate
without knowing where each treatment was located and
picked out the best looking tree. In 6 out of 8
replicates I picked out the Bravo treatment. It turned
out that one of the spray applications was close to
budbreak. By the spring of 1990 we had an emergency
exemption for use of Bravo on hazelnuts and a full
special local needs registration (SLN or 24 C) in
There have been close to 50 field trials during the
1990's that included Bravo but each with a specific
and often different objective.
Objectives have included different numbers of
applications, rates, timings and application methods.
When all of this information was combined, both good and
bad results, the average level of control was only 65%.
If we only consider the labeled rate then the average
level of control is 83% (30 trials). To
understand why Bravo is considered a good product we must
evaluate the data more closely.
For example, if we consider only trials evaluating
various numbers of applications at labeled rates we get a
different picture. A single application at budbreak
resulted in an average of 51% control but only 7 out of
11 trials resulted in control that that was significantly
better than no application at all. If another application
was applied two weeks after the bud break spray then the
average control is 59%. With a total of 3, 4, and 5
applications (all starting at bud break and 2 weeks
apart) then the average level of control jumped to 77, 90
and 85%, respectively. In addition, all of these later
trials were significantly better than no applications at
all. The data suggest that a total of 4 applications is
Rate trials with Bravo 720 have shown that as the rate
was reduced the level of control was reduced. The number
of significant trials also drops such that Bravo's
performance against EFB becomes similar to that observed
for the copper hydroxides.
A negative aspect of Bravo applications to hazelnuts
is the chance of increased summer sunburn. Spring
applications of Bravo have resulted in a noticeable
increase in sunburned leaves during August. Although this
does not affect yields it may increase the number of
leaves on the ground during harvest. The affect was only
observed on slow growing, non-vigorous trees. The
manufacturer suspected an interaction with other
pesticides, which we have not been able to duplicate.
Nevertheless, the label recommends that no other
pesticides, especially oils, be tank mixed with Bravo and
that Bravo applications not occur within one week of a
application of oil-based products.
Because of the volume of data and its effectiveness
against EFB, Bravo will be the standard by which we will
compare most other fungicides. There are other
formulations of chlorothalonil (such as Echo) which provide a
of efficacy. Home labels such as Bnoide Fung-onil or Hi-Yield Vegetable, Flower, Fruit and Ornamental fungicide can also be found.
Cabrio has a label for EFB and has also been tested unter the
code name BAS 500. Cabrio, like Abound and Flint, is a strobilurin (group 11 fungicide) and has
translaminar properties meaning that it moves into the plant tissue but
does not move with the transpiration stream. Cabrio is best used as a
protectant similar to the way Bravo is used. We observed 89% control in 5
trials when it was used in this way.
In one greenhouse trial, Cabrio was shown to have significant activity
when applied 2 days after spores of EFB were applied to young hazelnut
seedlings. This activity, however, was gone after 3 days.
Pristine also contains pyraclostrobin but in addition contains
Endura (boscalid). Endura did not do well with an average 17% control and
was not significatly different from trees that did not get treated with
any fungicide. Based on this result we are not recommending the use of
Pristine even though we have observed 93% control in 2 trials.
Use of copper as a fungicide has a long history
starting with the use of Bordeaux mixtures during the
1880's. Further developments of copper fungicides were
aimed at improving the handling and safeness to plants
over copper sulfate and lime mixtures while trying to
maintain its retention properties. The closest result was
the development of copper hydroxide.
Several formulations have been evaluated for efficacy
against EFB. Interest in these materials occurred early
since they were already registered on hazelnuts for
control of bacterial blight. Control has varied from 53%
to 89% over the years. In general, trials with copper
hydroxide products have been inconsistent unlike those
with Bravo. In some years, applications of these
materials even at highest labeled rates have not provided
significant control of EFB over using no fungicide at
all. This is why Bravo has been favored over copper
hydroxide products for control EFB.
There have been 6 trials where both Bravo and copper
hydroxide were in the same test, applied at the same
timings, in the same location, during the same year. In
these tests, the average level of control obtained for
the copper hydroxide materials was 72% compared to an
average of 79% for Bravo 720. So, in those years where
copper hydroxide works against EFB it works about as well
In all of the tests with copper hydroxide it was used
with the addition of supreme oil, as recommended on the
label. Oil alone was evaluated (0.25%) but was not found to be
effective against EFB. Some labels of copper hydroxide
still carry the old and outdated recommendation to use
dormant applications for the control of EFB. Only spring
applications when shoots are actively growing will be
effective against EFB.
(tebuconazole) and generics
Elite (tebuconazole) is in the DMI family of
fungicides (group 3) and has both locally systemic and kickback activity.
This product was the next generation from Bayleton, Bayer's first DMI
product. It is label on grapes and stone fruits as well as several other
crops under the Folicure label.
Use of Elite alone in 13 different research trials has resulted in an
average of 84% control of EFB. When compared head to head with Bravo the
average control was 84% for Elite and 90% for Bravo. Higher rates are
more effective. An average of 87% control was gotten at the 4 oz/100 gal
water rate comparied with
78% control at 2 oz/100 gal water. When
used in a
combined program using Bravo first at bud break followed by multiple
applications of Elite, there was an average of 97% control.
Elite can be used right at bud break unlike Rubigan. Some DMI
fungicides, like Rubigan, need a little more green tissue exposed after
bud break to be effective. Other fungicides, like Elite or Orbit, are
effective when starting applications at bud break. The flowable
formulation of tebuconazole, Folicure, does not seem to be equally
effective with an average control of 72% and only significant in 2 out of
An emergency exemption (section 18) for use of Elite on hazelnuts for
the control of EFB was issued by EPA for the 2000 and 2001 growing
seasons. The emergency use expired on May 30th, 2001 and was denied
The generics Tebucon and Tebuzol are registered for use on hazelnut. The
combination material Unicorn has both tebuconizole and sulfur. Although Unicorn
was effective we are not quite sure if sulfur alone will work on EFB. It might be
useful on the second application to also catch bug bud mite crawlers.
Gem or Flint
The registration of Flint for use on nut crops during the
summer of 2002 was a pleasant surprise. Flint is a strobilurin or group 11
fungicide and has
translaminar properties meaning that it moves into the plant tissue but
does not move with the transpiration stream. Flint is best used as a
protectant similar to the way Bravo is used. We observed 87% control in 7
trials when it was used in this way. The average dropped in 2003-04
when it did not preform as well as other chemicals such as Bravo.
In one greenhouse trial, Flint was shown to have significant activity
when applied 2 days after spores of EFB were applied to young hazelnut
seedlings. This activity, however, was gone after 3 days. This is very
exciting as other members of the strobilurin group (Abound and Sovran) did
not have any kickback activity.
A flowable formulation called Gem was introduced to the marketplace
2006. Technically, Flint is no longer registered for use on hazelnuts.
Luna Sensation also contains trifloxystrobin but in addition contains fluopyram. Fluopyram did not do well and was not
significatly different from trees that did not get treated with any fungicide. Based on this result we are not
recommending the use of Luna Sensation or any of the Luna products.
(propaconazole) and similar generics
The active ingredient propaconazole is sold by a
wide variety of trade names depending on the market and
location of the sales. Orbit is the name used for the
tree fruit and nut markets. Tilt was traditionally for
agrinomic crops such as grass seed. Generic names include Bumper and Propi-Max.
The average level of control when using Banner was 91% (7
trials) while 10 trials with Orbit have resulted in 82% control. Two
trials looked at only 3 applications for the season which
resulted in 74% control. Greenhouse trials
have show that Orbit has a 2-3 day
kickback activity aganst EFB and is greater when used
at higher rates.
An attempt to get a section 18 in 1999
was not sucessful but was granted in 2003, 2004, 2005 and
2006. A regular section 3 registration was obtained in 2007.
Application of Orbit will result in what is called plant
regulation (PGR) effects. The young developing shoots produce smaller,
greener leaves and shorter internodes. This picture shows normal
shoots on the right and shoots treated with Orbit on the left.
Shoots seem to grow out of the
effect 2 weeks after the last application. From 1994 to 1996, we sprayed
the same young Ennis trees with various amounts of Orbit (2 to 16 oz/A)
to see if there were any adverse effects on
yield. The PGR effects were seen each year and the average leaf area was
reduced at 4 or more oz/A. However, trees sprayed for 3 consecutive
years with 10 oz Orbit/A or 2 years with 16 oz Orbit/A did not result in
significant difference in fresh nut weight, fresh kernel weight or dried
kernel weight when compared with trees that had never been sprayed.
Research during 2002-03 and 2003-04 has shown that whether Orbit is
used for a total of 4 applications or once at bud break or once 6 weeks
after bud break, the average shoot length at the end of the seasion is
same as on trees that had not been sprayed with any fungicide at all.
In 1995, a few mature Barcelona trees were sprayed in commercial
orchards to see how growers might react to this PGR effect. Grower
comments included, "If the whole orchard were sprayed with Orbit you
never notice the difference or think anything was wrong." and "Does not
represent a significant problem."
A few combination products that contain propiconazole are registered and
recommended for control. The products include QuiltEcel and Stratego.
Procure (triflumizole) received an emergency section 18
registration in 2001 and 2002 and regular section 3 registration late
spring 2006 for use against EFB. Trials have tested Procure from 1.5 to
6 oz/100 gal water for an average of 78% control (17 trials).
Procure has the same mode of action (group 3) as Orbit, Elite or Rubigan.
We expect it to have similar curative or kickback properties, as do the
materials in this group. In one greenhouse trial, Procure was shown to
have significant activity when applied 2 to 3 days after spores of EFB
were applied to young hazelnut seedlings.
Procure has not shown a plant growth regulation (PGR) effect on
hazelnuts even though it is in the same chemical class as Orbit. Leaves
on Procure treated trees apear to have the same size and color as
Quash (active ingredient metconazole) is a new fungicide registered for use against EFB. Although it is new chemistry, it is in the same chemical group as Orbit,
Tilt, Procure and Rubigan (all group 3 materials). Tests for the last 4 years have found this material effective only at the 4 oz rate. However, better control
(91% in 2 trials) was found when a surfactant was used. We used the surfactant Regulaid but suspect any surfactant will help boost efficacy of this material. This
product can only be used in two sequential sprays before you must switch to a different product in a different chemical group.
QuiltXcel is a prepackaged mix of Orbit
(propiconazole, group 3) and Abound (azoxystrobin, group 11). This
material was tested during the 07-08 season at 3 rates from 10.5 to 17.5
fl oz/100 gal water. The average control was 99%. The label rate allows
use of 14 to 21 fl oz/A. As with any product that contains propiconazole
you will see a growth regulation effect of smaller deeper green leaves.
Hazelnuts begin to grow normally 2 weeks after the last application.
During the early 1990's we knew at least one of
the DMI fungicides would be needed for effective
management of EFB. To pursue a successful registration we
needed an effective material with a good toxicology
package and manufacturer support. Dow Elanco seemed most
interested and with early efficacy data we focused on
obtaining a registration for Rubigan. The first emergency
exemption was issued in the spring of 1994 but we are
still awaiting a section 3 registration.
Over the years we have found that although Rubigan has
2-3 day kickback activity against EFB it was not a
material to use exclusively.
The overall average from all of our trials was 39%
control. When compared one to one with Bravo under the
same conditions Rubigan averaged 46% control while Bravo
averaged 88% control out of 8 trials. Use of this
material is restricted to a combined program first
utilizing protectants like Bravo then systemic products
such as Rubigan. This stratagy has resulted in an average
99% control in 12 trials.