Kevin in a follow up to Larry's reply we have been seeing this disorder in Nova Scotia for a number of years. I was in a block of Marshal McIntosh on M26 this week setting out plots and noted that a number of tees that had swollen buds but were not at green tip like the remainder of the block. I checked the bud and they were still green but checking the cambium layer on the limb is was brown This block is 15 plus years old. The problem has shown up periodically in this block for a number of years. A portion or the hole tree is affected. The infection is in the scion and not the rootstock. Dr Gordon Braun a plant pathologist with AAFC has isolated Gloeosporium alubum form infected trees with these symptoms. Nova Scotia had a very wet fall but mild winter and thus we would attribute the disorder to a pathogen.
Bill Craig Horticulture Specialist AgraPoint Kentville NS From: [email protected] [mailto:[email protected]] On Behalf Of Kevin A. Iungerman Sent: April-09-10 2:28 PM To: Apple-Crop Subject: RE: Apple-Crop: sickness in the Pioneer Mac block Larry, Can you let us know the age of those Northern Spy at the time you saw the situation described? It would be useful to know this tree age was specified in the MI example, and figures prominently in Rosenberger's cited Marshall Mac situation in New York and New England. Thanks. Kevin Iungerman Greetings, I had what sounds to be the exact same problem a number of years ago with Northern Spy on M-26. The most vigorous trees were the most seriously affected. We had a heavy crop the year before and a long wet fall. The tops had long sunken, purplish lesions, and they died from the tops down. The bottom foot above the union was still good in most cases. Some tree I pulled out and the rest I cut off below the lowest lesion. Within three years I had the trees back almost as large as they were. I shouldn't have pulled the others in hindsight. It affected about fifteen to twenty percent of the trees in the block. We had some isolates taken, and as I recall it was identified as an aerial version of Phytophora. No one locally had heard tell of this organism causing symptoms above the crown. This block was on well drained, gravelly loam soil, so there was no water ponding or imperfect drainage. The only good news is that the trees recovered and it hasn't been back since in that block, although I do see it occasionally in other blocks of different varieties and rootstocks. I saw some on Idared on MM-111 that were at least 25 years old recently. Mark, I am sure I still have some pictures that I could send you for comparison if you like. Regards, Larry Lutz Nova Scotia ________________________________ From: [email protected] [mailto:[email protected]] Sent: April 8, 2010 9:42 PM To: [email protected] Subject: Apple-Crop: sickness in the Pioneer Mac block Hello all, In 08 a neighbor with a 5 yr old Pioneer Mac block on G30 saw extensive amounts of die-back in his trees, starting with trees hanging onto their leaves going into late fall. Spring of 09 showed that the most vigorous trees were affected to the greatest degree with whole limbs, leaders and some entire trees dying. Everything looked good in the spring of 09 in our orchard, which is 7 yr old P-Mac on M26. We wondered if our neighbor had a problem because of G30. Many "experts" looked at his trees and the consensus was "winter injury". In early October we harvested our block and noticed nothing of concern (except scab). In mid-November we saw trees throughout the block with dark leaves that refused to fall. The most vigorous trees seem to be the most affected. Whole limbs seem to die from the tip to or near the truck. Leaders often turned dark brown down to just above the lower scaffold limbs. Trunks below this point are mostly unaffected. Most trees seem to be O.K. at this point in time but nearly 20% of the block has some degree of this malady. None of our other varieties have this problem. Does anyone have experience with this sort of situation? Any ideas would be appreciated. Mark Evans, Northwest Michigan __________ Information from ESET NOD32 Antivirus, version of virus signature database 5011 (20100408) __________ The message was checked by ESET NOD32 Antivirus. http://www.eset.com __________ Information from ESET NOD32 Antivirus, version of virus signature database 5012 (20100409) __________ The message was checked by ESET NOD32 Antivirus. http://www.eset.com -- Kevin Iungerman, Extension Associate Cornell University Cooperative Extension's Northeast NY Commercial Fruit Program 50 West High Street, Ballston Spa, NY 12020 Phone: (518) 885-8995 FAX: (518) 885-9078 email: [email protected] website: Coming in 2010. Providing Equal Opportunity Commercial Tree Fruit and Grape Research, Education and Programming with the Support of the Farmers and Cornell Cooperative Extension Associations of Albany, Clinton, Essex, Saratoga, and Washington Counties, and Cornell University's College of Agriculture and Life Science. Serving NY's Upper Hudson and Champlain Region - Home to Premium Cold Hardy Orchard and Vineyard Fruit, Including: McIntosh, Honeycrisp, and Sweetango Apples, and Marquette and LaCrescent Grapes! "Suggestions? Comments? Ideas? Possibilities begin with people sharing ideas and working together."
