WTNUT
5 year old buck +
Sorry here it is. View attachment 5527
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Fire Blight cankers and thoughts
- Thread starter WTNUT
- Start date
WTNUT
5 year old buck +
This is pretty funny and goes to show you how attached I am to my apple, pear and peach trees (apples being my favorite). When I got home yesterday, my wife of 24 years asked me how my day was. I told her "not good, I had to cut down 12 of my oldest apple trees". Now she is a lovely wife for many reasons, but compassion is NOT her strong point when it comes to yours truly. With our daughter yes she is, but she has been with me long enough to think I can handle anything. Well I doubt if I would have received the compassion I received from her yesterday evening had I told her I just lost one arm and one leg! She would have said "you still have one of each deal with it". But, when she heard I had to cut those trees she felt really bad for me. She and my daughter tease me by saying I care more about trees now than hunting - and they are right :) You gotta love that habitat and anything about it that is a special as fruit trees.
WTNUT
5 year old buck +
One of my FB trees looked EXACTLY LIKE THAT last year and there were no shepherd hooks, no damage leaves, nothing. This year that cancer was everywhere. I don't know if yours is FB for sure, but I would be trying to perform surgery on that late winter.
aerospacefarmer
5 year old buck +
Here is an update from Penn State Extension in Biglerville very near Adams County Nursery as to why you may be getting fb and shot blight and what to do which isn't much. FYI guys. I get these updates weekly and I also get the weekly Fruit Times from Penn State. Good info for sure
Disease Update: Where Are Those Fire Blight Strikes Coming From?
Tags: Plant Pathology, Young Growers
Posted: June 16, 2015
Conditions have been optimal for canker blight: leftover fire blight cankers continue to grow and bacteria move within the tree to growing areas causing shoot blight. Shoot blight is also occurring to those who experienced blossom blight, as well. Leafhoppers are active and will cause wounds in growing shoot tips, creating entry points for bacteria to enter. Pruning blighted areas and managing insects are the best methods for control.
Shoot blight resulting from bacteria moving within the tree from overwintering cankers to growing shoots. (Photo: K. Peter)
In the last couple of weeks, fire blight symptoms have been showing up and questions have been rolling in: I didn't have blossom blight, where did the shoot blight come from? I haven't experienced hail, where did the shoot blight come from? I've never had fire blight, where did the shoot blight come from? This season, Mother Nature has provided excellent conditions (again) to illustrate the importance of those overwintering fire blight cankers... If you've been asking yourself the above questions, the answer is: from cankers left in the tree. Look closely, I'm sure you'll be able to find them... In some cases, I have seen blossom blight and the characteristic shoot blight that surrounds the blighted area; however, I'm seeing more shoots wilting and dying as a result of cankers leftover in the trees: this is canker blight. What is canker blight and how do the shoots die a result of it? Let's review...
A review about the importance of cankers and canker blight
Canker blight is often a head scratcher and, consequently, grossly underestimated for its ability to cause damage in the orchard. Canker blight develops due to renewed activity by the bacteria at the margins of overwintering cankers from the previous season and occurs regularly every year where the disease is established. In other words, if cankers are left in your trees, you can count on canker blight. The first symptom can be detected by cutting into the bark at the canker margin where you will see a narrow zone of water-soaked green or diffuse brown tissue at the margin between the necrotic tissue of the canker and the surrounding healthy bark. The bacteria move systemically from the canker into nearby growing, succulent vegetative tissue. Often times, water sprouts close to active canker sites will develop a distinct yellow to orange color and begin to wilt. Canker blight symptoms are often overlooked because of their similarity to the more familiar shoot tip (shoot blight) infections that occur later. Another distinct feature is canker blight "shoot blight" will appear as if the infection is starting from the base of the shoot, as opposed to the shoot tip, which is characteristic of typical shoot blight. In years when blossom infection events do not occur or have been well controlled, active canker sites serve as the primary source of bacteria for a continuing epidemic of secondary shoot blight infections that can lead to major limb, fruit and tree losses. Such sources of bacteria can also be important for new orchards with no history of fire blight when they occur in older, surrounding orchards from which the bacteria can be moved into young orchards by wind, blowing rain and certain insect species.
In contrast to characteristic "shoot blight"...
Shoot tip infections are incited on the youngest 2-3 tender, un-expanded leaves at the tips of vegetative shoots. The symptoms of these shoot tip infections differ from those of the systemically invaded shoots associated with canker blight in that the shoot tips are usually still green (not yellow to orange) when they wilt. The significance of these infections are twofold: 1) they tend to progress downward rapidly, often invading and destroying larger supporting limbs; and 2) as bacteria becomes abundant in the orchard, leaf surfaces are colonized by the bacteria (arriving from earlier blossom infections, active cankers or young shoots systemically invaded by bacteria from nearby cankers), but cause no harm so long as they remain on the surface and there is no injury. Unfortunately, injury can easily occur. When potato leafhoppers feed on shoot tips, they will cause damage, thereby creating an entry for the bacteria to enter the plant. A more likely factor for injury is wind, and it does not necessarily need to be high winds associated with storms. Research has shown clear evidence that the simple damage to leaf hairs along the midrib of pear leaves provides suitable wounds for the bacteria to enter and to incite infections leading to typical shoot blight symptoms. Thus, the greatest number of shoot tip infections can occur during days with gusty winds that might cause a whipping type injury to shoot tip leaves, an event that is, unfortunately, all too common in the temperate climates where apples and pears are grown.
Are there management options?
If you are experiencing "shoot blight" AND you know you have overwintering cankers in your trees, the only management option is to prune out the affected parts of the trees. There are no topical spray applications you can use to control this version of shoot blight: the infection is coming from inside the tree and not outside. Once terminal bud set occurs, the tree stops growing and the bacteria stop moving within the tree. The shoot blight as a result of canker blight should stop. However, a lot of damage and establishment of more cankers can develop between now and terminal bud set.
The 4-1-1 for cutting out infections
All of those infected shoots and cankers are oozing like crazy right now. Consequently, a lot of bacteria are hanging around the tree just biding their time until an opening presents itself. Since insects can cause wounds, which are entry points for the bacteria, be sure to control piercing-sucking insects, such as aphids, leafhoppers, and pear psylla.
Contact Information
Kari Peter, Ph.D.
Phone: 717-677-6116 x223
You received this email because you are subscribed to the FRUIT-TIMES-L mailing list. If you would like to unsubscribe from this list, simply send an email to FRUIT-TIMES-L-UNSUBSCRIBE-REQUEST@LISTS.PSU.EDU. No subject or message is necessary in the email For any questions or problems, email FRUIT-TIMES-REQUEST@LISTS.PSU.EDU
Disease Update: Where Are Those Fire Blight Strikes Coming From?
Tags: Plant Pathology, Young Growers
Posted: June 16, 2015
Conditions have been optimal for canker blight: leftover fire blight cankers continue to grow and bacteria move within the tree to growing areas causing shoot blight. Shoot blight is also occurring to those who experienced blossom blight, as well. Leafhoppers are active and will cause wounds in growing shoot tips, creating entry points for bacteria to enter. Pruning blighted areas and managing insects are the best methods for control.
Shoot blight resulting from bacteria moving within the tree from overwintering cankers to growing shoots. (Photo: K. Peter)
In the last couple of weeks, fire blight symptoms have been showing up and questions have been rolling in: I didn't have blossom blight, where did the shoot blight come from? I haven't experienced hail, where did the shoot blight come from? I've never had fire blight, where did the shoot blight come from? This season, Mother Nature has provided excellent conditions (again) to illustrate the importance of those overwintering fire blight cankers... If you've been asking yourself the above questions, the answer is: from cankers left in the tree. Look closely, I'm sure you'll be able to find them... In some cases, I have seen blossom blight and the characteristic shoot blight that surrounds the blighted area; however, I'm seeing more shoots wilting and dying as a result of cankers leftover in the trees: this is canker blight. What is canker blight and how do the shoots die a result of it? Let's review...
A review about the importance of cankers and canker blight
Canker blight is often a head scratcher and, consequently, grossly underestimated for its ability to cause damage in the orchard. Canker blight develops due to renewed activity by the bacteria at the margins of overwintering cankers from the previous season and occurs regularly every year where the disease is established. In other words, if cankers are left in your trees, you can count on canker blight. The first symptom can be detected by cutting into the bark at the canker margin where you will see a narrow zone of water-soaked green or diffuse brown tissue at the margin between the necrotic tissue of the canker and the surrounding healthy bark. The bacteria move systemically from the canker into nearby growing, succulent vegetative tissue. Often times, water sprouts close to active canker sites will develop a distinct yellow to orange color and begin to wilt. Canker blight symptoms are often overlooked because of their similarity to the more familiar shoot tip (shoot blight) infections that occur later. Another distinct feature is canker blight "shoot blight" will appear as if the infection is starting from the base of the shoot, as opposed to the shoot tip, which is characteristic of typical shoot blight. In years when blossom infection events do not occur or have been well controlled, active canker sites serve as the primary source of bacteria for a continuing epidemic of secondary shoot blight infections that can lead to major limb, fruit and tree losses. Such sources of bacteria can also be important for new orchards with no history of fire blight when they occur in older, surrounding orchards from which the bacteria can be moved into young orchards by wind, blowing rain and certain insect species.
In contrast to characteristic "shoot blight"...
Shoot tip infections are incited on the youngest 2-3 tender, un-expanded leaves at the tips of vegetative shoots. The symptoms of these shoot tip infections differ from those of the systemically invaded shoots associated with canker blight in that the shoot tips are usually still green (not yellow to orange) when they wilt. The significance of these infections are twofold: 1) they tend to progress downward rapidly, often invading and destroying larger supporting limbs; and 2) as bacteria becomes abundant in the orchard, leaf surfaces are colonized by the bacteria (arriving from earlier blossom infections, active cankers or young shoots systemically invaded by bacteria from nearby cankers), but cause no harm so long as they remain on the surface and there is no injury. Unfortunately, injury can easily occur. When potato leafhoppers feed on shoot tips, they will cause damage, thereby creating an entry for the bacteria to enter the plant. A more likely factor for injury is wind, and it does not necessarily need to be high winds associated with storms. Research has shown clear evidence that the simple damage to leaf hairs along the midrib of pear leaves provides suitable wounds for the bacteria to enter and to incite infections leading to typical shoot blight symptoms. Thus, the greatest number of shoot tip infections can occur during days with gusty winds that might cause a whipping type injury to shoot tip leaves, an event that is, unfortunately, all too common in the temperate climates where apples and pears are grown.
Are there management options?
If you are experiencing "shoot blight" AND you know you have overwintering cankers in your trees, the only management option is to prune out the affected parts of the trees. There are no topical spray applications you can use to control this version of shoot blight: the infection is coming from inside the tree and not outside. Once terminal bud set occurs, the tree stops growing and the bacteria stop moving within the tree. The shoot blight as a result of canker blight should stop. However, a lot of damage and establishment of more cankers can develop between now and terminal bud set.
The 4-1-1 for cutting out infections
- Do not cut out infections during wet weather since bacteria move via water.
- Cut out active infections early - before necrosis develops (limits the spread of bacteria).
- Pruning is most effective when incidence is low.
- Focus on salvaging tree structure and young high density plantings when incidence is high.
- Avoid excessive cutting since this stimulates secondary shoot growth.
- Bacteria can invade healthy tissue up to ~3 feet in advance of visible symptoms, which makes tool sterilization not effective
- Practice the ugly stub method: cut 6 -12 inches below the margin of visible infection and remove later during winter pruning.
- Bacteria can live very well outside the plant and, to be certain you are getting rid of all sources of bacteria, it best to burn infected tissue that has been removed from the tree.
All of those infected shoots and cankers are oozing like crazy right now. Consequently, a lot of bacteria are hanging around the tree just biding their time until an opening presents itself. Since insects can cause wounds, which are entry points for the bacteria, be sure to control piercing-sucking insects, such as aphids, leafhoppers, and pear psylla.
Contact Information
Kari Peter, Ph.D.
- Assistant Professor
Phone: 717-677-6116 x223
You received this email because you are subscribed to the FRUIT-TIMES-L mailing list. If you would like to unsubscribe from this list, simply send an email to FRUIT-TIMES-L-UNSUBSCRIBE-REQUEST@LISTS.PSU.EDU. No subject or message is necessary in the email For any questions or problems, email FRUIT-TIMES-REQUEST@LISTS.PSU.EDU
WTNUT
5 year old buck +
It has been seven days since I cut the FB stricken trees. The trees have been removed and I have not seen a single new strike on any of the trees in the orchard. I may have not removed them but for the fact that I had several 3rd to 5th leaf trees each with a single strike (which I removed immediately). I did not want it to spread. It looks like all of the trunks are doing well. Each has a small nurse limb for the remainder of the year. I will cut several inches off the trunks next year and graft some disease resistant varieties on to them. So it looks like things are looking up and I will look closely for cankers this winter.
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