RE: Apple-Crop: Mystery disease?
Thank you for the photos of what appears to be viroid affected apples. For your information, we have photos on our web site of fruit tree diseases caused by virus and virus-like agents (http://nrsp5.prosser.wsu.edu/nrspviru.html ) that some of you might find useful. Bill Howell National Clean Plant Network-Fruit Trees 24106 N. Bunn Road Prosser, WA 99350 http://nrsp5.prosser.wsu.edu -Original Message- From: apple-crop@virtualorchard.net [mailto:apple-c...@virtualorchard.net] On Behalf Of Claude Jolicoeur Sent: Monday, December 06, 2010 7:44 AM To: Apple-Crop Subject: Re: Apple-Crop: Mystery disease? A 22:41 10.12.05 -0500, vous avez écrit : I suspect that the apple tree that bears these fruit is infected with the dapple apple/scar skin viroid. Thank you very much Dave and Jean-Marc. The informations you have provided are very informative and useful. In addition, I have found some pictures of this disease on the internet and unfortunately I have to agree with your diagnosis. I say unfortunately because from what I can see, there is no other issue than destruction of the affected tree. There doesn't seem to be any cure! And there is a risk of this viroid to spread to the rest of the orchard - a risk I am not ready to take! This seems to be a pretty exotic and rare disease. I probably have introduced it when I grafted some Wealthy apple on this seedling root in 1986. The source tree was obviously infected. To Jean-Marc, I also found a fiche descriptive en francais from the INRA here: http://www-intranet.angers.inra.fr/dossiers/virus/fichvir4.html where the first picture corresponds to the damage I can see on my tree. Also, the second picture on page 2 of the CTIFL document is very similar to my problem. Thanks for the help. Claude Jolicoeur Orchardist and cider maker Zone 4, Quebec -- The 'Apple-Crop' LISTSERV is sponsored by the Virtual Orchard http://www.virtualorchard.net and managed by Win Cowgill and Jon Clements webmas...@virtualorchard.net. Apple-Crop is not moderated. Therefore, the statements do not represent official opinions and the Virtual Orchard takes no responsibility for the content. -- The 'Apple-Crop' LISTSERV is sponsored by the Virtual Orchard http://www.virtualorchard.net and managed by Win Cowgill and Jon Clements webmas...@virtualorchard.net. Apple-Crop is not moderated. Therefore, the statements do not represent official opinions and the Virtual Orchard takes no responsibility for the content.
RE: Apple-Crop: Mystery disease?
Hi Claude I agree with Dave on dapple apple viroïd hypothesis You will find here after a link on the description of the disease in our book on Viruses diseases of fruit trees. You are lucky its one of very few books that were published in English...!! See in the last page the table with variety sensitivity https://docs.google.com/viewer?a=vpid=explorerchrome=truesrcid=0Bx19mxjKQl22M2MwYTJkOTktNDkyZC00MDE2LTk1OTctNGVlY2Q4Y2IwNmNihl=enauthkey=CNOH89UE Hope this helps, and that the link will work for you. JM Jourdain Jourdain**(at)**Ctifl.fr -Message d'origine- De : apple-crop@virtualorchard.net [mailto:apple-c...@virtualorchard.net] De la part de Claude Jolicoeur Envoyé : dimanche 5 décembre 2010 20:28 À : Apple-Crop Objet : Apple-Crop: Mystery disease? Dear apple-croppers... Last year at this time of the year, we had a fun thread on a mystery apple. This year, I would propose one on a mystery disease... Hopefully it will trigger just as much interesting discussion! I have taken pictures showing the symptoms/damage. Please look here: http://picasaweb.google.com/cjoliprsf/AppleDisease2010 Let me give you a little information on this: - Pictures were taken on August 14 2010 - The size of the apples on the picture is about 1 inch across - The apples didn't grow any bigger during fall - All the apples show the same symptoms - There is only one tree affected in the orchard (a small 1 acre orchard) - Affected variety: Wealthy (there are other Wealthy trees around that are normal) - This appeared about 5 years ago and reappears every year on this particular tree - The affected apples ripen later than normal - actually, they don't really ripen, but they stay attached on the tree until snow. - The foliage is otherwise healthy and the tree normally vigorous - Other trees about 20 feet away do not show any similar symptoms Thanks for looking at this. Claude Jolicoeur Orchardist and cider maker Zone 4, Quebec -- The 'Apple-Crop' LISTSERV is sponsored by the Virtual Orchard http://www.virtualorchard.net and managed by Win Cowgill and Jon Clements webmas...@virtualorchard.net. Apple-Crop is not moderated. Therefore, the statements do not represent official opinions and the Virtual Orchard takes no responsibility for the content. -- The 'Apple-Crop' LISTSERV is sponsored by the Virtual Orchard http://www.virtualorchard.net and managed by Win Cowgill and Jon Clements webmas...@virtualorchard.net. Apple-Crop is not moderated. Therefore, the statements do not represent official opinions and the Virtual Orchard takes no responsibility for the content.
RE: Apple-Crop: Mystery disease?
Just for interest, it seems this mystery disease is solved, but we had some Empire apples treated with Agogee last year that looked very similar. Learn from our mistakes! Doug and Leslie Balsillie -Original Message- From: apple-crop@virtualorchard.net [mailto:apple-c...@virtualorchard.net] On Behalf Of Claude Jolicoeur Sent: Monday, December 06, 2010 10:44 AM To: Apple-Crop Subject: Re: Apple-Crop: Mystery disease? A 22:41 10.12.05 -0500, vous avez écrit : I suspect that the apple tree that bears these fruit is infected with the dapple apple/scar skin viroid. Thank you very much Dave and Jean-Marc. The informations you have provided are very informative and useful. In addition, I have found some pictures of this disease on the internet and unfortunately I have to agree with your diagnosis. I say unfortunately because from what I can see, there is no other issue than destruction of the affected tree. There doesn't seem to be any cure! And there is a risk of this viroid to spread to the rest of the orchard - a risk I am not ready to take! This seems to be a pretty exotic and rare disease. I probably have introduced it when I grafted some Wealthy apple on this seedling root in 1986. The source tree was obviously infected. To Jean-Marc, I also found a fiche descriptive en francais from the INRA here: http://www-intranet.angers.inra.fr/dossiers/virus/fichvir4.html where the first picture corresponds to the damage I can see on my tree. Also, the second picture on page 2 of the CTIFL document is very similar to my problem. Thanks for the help. Claude Jolicoeur Orchardist and cider maker Zone 4, Quebec -- The 'Apple-Crop' LISTSERV is sponsored by the Virtual Orchard http://www.virtualorchard.net and managed by Win Cowgill and Jon Clements webmas...@virtualorchard.net. Apple-Crop is not moderated. Therefore, the statements do not represent official opinions and the Virtual Orchard takes no responsibility for the content. -- The 'Apple-Crop' LISTSERV is sponsored by the Virtual Orchard http://www.virtualorchard.net and managed by Win Cowgill and Jon Clements webmas...@virtualorchard.net. Apple-Crop is not moderated. Therefore, the statements do not represent official opinions and the Virtual Orchard takes no responsibility for the content.
Re: Apple-Crop: Mystery disease?
I suspect that the apple tree that bears these fruit is infected with the dapple apple/scar skin viroid. Copied below is an article about the diseases caused by this viroid that I put into Scaffolds fruit journal in September of 1994. I have photos very similar to yours that I took in an old Empire orchard in the Hudson Valley in the late 1980's or early 1990's, but the scar-skin symptoms seem to be relatively rare. I'm not certain if any more work has been done on this viroid in the past 16 years. Following is the old article that I wrote in 1994: A fruit disorder known as dapple apple has appeared this fall in several commercial orchards in the Hudson Valley. On affected fruit, circular patches of the skin fail to develop red color and remain green or faintly pink. The poorly colored circular areas may overlap to produce irregular blotchy areas on the fruit. As the fruit become fully mature, the green areas turn bright yellow, giving the fruit a marbled appearance. A more severe manifestation of the same disease is known as scar skin. On apples affected by scar skin, the sides and calyx ends of affected fruit develop a rough skin in early summer. The roughened skin then develops numerous small cracks as the fruit mature. Fruit with scar skin have the appearance of fruit that received severe spray burn or had a limb rub. I have seen dapple apple on Macoun four or five times over the past 15 years, but symptoms this year are the most spectacular I have ever seen. Other varieties may also show symptoms. In a mixed planting of 15-20 year-old Macoun, Empire, and McIntosh, several Empire trees showed severe scar skin while other Empire trees had dapple apple or no symptoms at all. All of the Macoun trees and most fruit on each tree showed distinct dapple apple symptoms. A few dapple apple symptoms were found on McIntosh, but the proportion of affected fruit was quite low and severity of symptoms was much less than on Macoun. Dapple apple was first reported in the United States in 1956 and was associated with trees propagated on Virginia crab rootstock or stem pieces. The disorder was assumed to be a virus disease until the early 1980's when Japanese researchers showed that dapple apple and a related disorder called scar skin are both caused by viroids. In general terms, a viroid can be described as a virus without a protein coat. Many viruses can be eliminated from propagation material by heat treatments which damages the viral protein and thereby eliminates the virus. Because viroids have no coat protein, they are very heat resistant and therefore more difficult to eliminate from propagating material. All reports in the literature (and there aren't many!) suggest dapple apple is only transmitted by root grafting and by using contaminated propagating materials. However, I would guess that over a period of years, the disorder might move from one tree to the next with an orchard by some means that has not yet been identified. Movement within orchards is certainly very slow if it occurs at all. Why is the disorder evident this year in 15-20 year-old trees that never showed symptoms before? No one knows, but the best guess is that certain undefined weather conditions are required for symptom development. The critical period for determining whether or not symptoms appear may be the period during and shortly after bloom. Because symptoms development is probably weather dependent, trees with dapple apple symptoms this year may produce unblemished fruit next year. Thus, I do not think that growers should necessarily remove trees which produced fruit with dapple-apple for the first time this year. Fruit from the same trees may show no symptoms next year. However, growers may wish to mark affected trees for observation next year and then remove those trees that are consistently produced blemished fruit. Can dapple apple survive in soil and affect trees replanted into a site from which trees with dapple apple were removed? Probably not, but there is a possibility that new trees could root graft to living tree roots left in the soil after orchard renovation. Thus, growers opting to remove severely affected trees should avoid replanting with highly susceptible cultivars such as Macoun, Delicious, Empire, and Spartan. Golden Delicious reportedly do not develop symptoms when infected, and symptoms on infected McIntosh, Mutsu, Idared and Jonathan are quite mild. Susceptibility of other varieties is unknown. Dear apple-croppers... Last year at this time of the year, we had a fun thread on a mystery apple. This year, I would propose one on a mystery disease... Hopefully it will trigger just as much interesting discussion! I have taken pictures showing the symptoms/damage. Please look here: http://picasaweb.google.com/cjoliprsf/AppleDisease2010 Let me give you a little information on this: - Pictures were taken on August
