Eastern Filbert Blight

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Helping farmers find, destroy, and manage EFB


What is Your Risk from Eastern Filbert Blight?

Jay W. Pscheidt, John Pinkerton and Ken B. Johnson

When you first discover Eastern Filbert Blight (EFB) in your orchard it can be overwhelming. The disease typically has already been there for several years. What you see today is only the tip of the iceberg since there are many more infections that will not show up until the next year. Growers in the southern Willamette Valley are concerned but have not implemented many recommendations that could reduce their risk from EFB. Management of eastern filbert blight will require the use and integration of many tools by the entire hazelnut industry. 

The EFB risk table was developed so growers could determine the EFB risk of their orchards. It indicates the most important factors that influence the development of EFB in their orchards. It also indicates ways in which one could reduce the overall orchard risk.

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On this page
Overall Risk*
Where is EFB?
Hazelnut Cultivar
Scouting for EFB
Fungicide Applications
Sanitation

Risk*
Where is EFB?
Hazelnut Cultivar
Scouting
for EFB
Fungicide Applications

(Susceptible cultivars)

Sanitation

(Any Orchard
with EFB)

High

In Your Orchard

Casina
Daviana
Du Chilly
Ennis
Negret
TGDL
Tonda Romana

Never

None

No canker removal

Medium

In an Adjacent Orchard only

Barcelona
Butler
Hall's Giant
Willamette

Once per year

1 to 2

Partial
canker
removal

Low

In Local Area only

Clark
Lewis
TDG

Twice per year

(Late Summer
and Winter)

>3

Canker removal before budbreak

None

----

Santiam
Yamhill
Jefferson
Dorris
Wepster

----

----

No EFB to remove

*For those folks who would like to give their orchard a numerical score;
High = 3
Medium = 2
Low =1
None = 0
 
Highest possible score is 15 while lowest score is 1 to 3 (No hazelnut orchard in Oregon is EFB-risk free).
Your overall EFB risk is
High if your orchard score is 10 or more
Medium if your orchard score is 6 to 9
Low if your score is 5 or less


EFB Location

The location of active cankers relative to your orchard is an important factor. Having active cankers within your orchard is the highest risk. A medium risk is assigned if only adjacent orchards have EFB and a low risk occurs if the disease is just in the local area. There are no orchards in the Willamette Valley where the risk is zero. We now have EFB from Portland to Eugene. Even orchards of the highly resistant 'Jefferson' can become infected if planted next to a heavily infected orchard of 'Ennis" or 'Barcelona".

Cultivar Susceptibility

Cultivar susceptibility is another highly important factors that influences EFB risk. Orchards with highly susceptible cultivars such as Ennis or Daviana have the highest risk. An orchard only of Barcelona would have a medium risk, however, many of these orchards have Daviana pollinizers. This means the orchard as a whole has a higher than medium risk of EFB but in general has a lower risk than an orchard of mostly Ennis. Resistant cultivars such as Santiam, Yamhill, Jefferson, Dorris or Wepster would reduce the EFB risk to zero as long as immune pollinizers are used.

Reducing the amount of susceptible tissue will reduce your EFB risk. Reduce your risk by replacing those 'Daviana' trees. Don't wait for EFB to start. Many growers that have been battling EFB for many years have said they wished they had removed their most susceptible cultivars and pollinizers much earlier than they actually did. Removing wild seedlings and suppressing suckers will also reduce your overall EFB risk.

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Scouting

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! The earlier EFB is detected the more effective the various EFB control tactics are at managing the problem. EFB has even been eradicated from a few orchards due to early detection. 

Scouting does not mean looking up at the trees occasionally while you are sucker spraying or flailing. (Although many cankers have been spotted this way.) What I mean by scouting is actually taking the time to investigate your orchard specifically for EFB. Look over many of the susceptible pollinizers, investigate any dead branch, slow or poor growth, etc. Flagging branches can be found in late summer after the canker has girdled the branch. During the dormant season, especially on clear days, you can see into the canopy better and find more cankers. Scout your orchards at least twice a year for the lowest EFB risk.

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Fungicides

Fungicides protect healthy tissue and are recommended for all orchards in the Willamette Valley. A total of 4 fungicide applications are needed starting at budbreak (early to mid-march) and continuing at regular intervals (every 2 weeks depending on the weather) until early May. This is the minimum spray requirement to consistently reduce the disease spread in orchards with established infections. We even recommend an application at bud break for newly planted resistant orchards when located next to heavily infected orchards.

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Sanitation

Pruning is the ONLY way to remove EFB from the tree and reduce the overall risk. Susceptible trees with many cankers MUST be removed. Resistant trees with one or two cankers can be lightly pruned (be sure to cut 1 to 3 feet below the visible canker). Recommendations for scenarios between these two extremes will be different for each grower depending on orchard arrangement, resources and your personal philosophy. If we must error then error by cutting too much wood or removing too many trees than not enough. EFB will come back if you don't get it all. 

The infected wood also must be destroyed before budbreak. The fungus can continue to produce spores from cankers sitting in brush piles within or next to the orchard. Burn, bury or chip brush piles to reduce your EFB risk.

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Overall Risk

Score each risk factor and then add them up to assign an overall EFB risk for your orchard. For each column let High = 3, Medium = 2, Low =1 and None = 0. The total score is calculated by adding up each number from each column. The highest possible score is 15 while lowest score is usually from 1 to 3. No hazelnut orchard in Oregon is EFB-risk free with a total score of zero. Your overall EFB risk is HIGH if your orchard score is 10 or more, MEDIUM if your orchard score is 6 to 9 and LOW if your score is 5 or less. 

One of the problems we have in the hazelnut industry are orchards in the southern Willamette Valley. Intensive scouting and fungicide applications are recommended but not practiced due to the high cost of these measures. Mangers do not want to deal with the problem until it is too late. They think they have a LOW EFB risk but in actuality may have a HIGH risk.

An Ennis orchard in this area can serve as an example. The manager may feel they are far enough south not to worry about EFB (a 0 risk for the first column). It is still Ennis (EFB risk 3), they scout (risk 1) but do not apply fungicides (0 if far enough south) and there is no EFB to remove (0 risk). The overall risk they believe is LOW (0+3+1+0+0 = 4).

But what if they do have EFB in the orchard? A real possibility! It is in the orchard (risk 3), growing Ennis (3), not really scouting all that well (2), no fungicides (3) and no canker removal (3). Then they are operating under an overall HIGH EFB risk (3+3+2+3+3 = 14). This, among other reasons, is why EFB will continue to spread throughout the entire Willamette Valley.

Hazelnut growers can easily lower a HIGH risk orchard to a MEDIUM risk orchard by integrating EFB control tactics. It is much more difficult if not impossible to take an existing orchard and make it a LOW risk orchard. LOW risk orchards must be created by replanting with resistant cultivars.

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