Re: [apple-crop-2] Apple leaf disorder
It could be Marssonina leaf blotch, which has been appearing in orchards this time of year – we first identified this in Pennsylvania last September and I’m aware of incidences in NY, NJ, and CT. It’s rearing its head again this season, most likely due to the feet of rain we have received since July. I recently wrote an article for PSU’s Fruit Times: https://extension.psu.edu/2018-disease-update-marssonina-blotch-on-apple-trees Moral of the story: treat it like you would deal with apple scab. Sanitation will be key keeping this disease in check year to year. Kari Peter, Ph.D. Assistant Research Professor - Tree Fruit Pathology Department of Plant Pathology and Environmental Microbiology Penn State Fruit Research and Extension Center 290 University Dr., P.O. Box 330 Biglerville, PA 17307-0330 Office: 717-677-6116 Ext. 223 Fax: 717-677-4112 E-mail: ka...@psu.edu<https://webmail.psu.edu/webmail/shell.cgi?timestamp=1362517824> Twitter: https://twitter.com/drtreefruit From: apple-crop-boun...@virtualorchard.com On Behalf Of maurice tougas Sent: Tuesday, October 09, 2018 12:36 PM To: Apple-Crop discussion list Subject: Re: [apple-crop-2] Apple leaf disorder Yup seeing same here. No captan or phosphorous . Goldens but I don't recall seeing on Jonagold. Ill check. Mo Tougas On Tue, Oct 9, 2018 at 12:26 PM David Kollas mailto:kollasorchar...@gmail.com>> wrote: The photo below, taken yesterday in my orchard, shows a Jonagold tree among other Jonagold trees that are dropping leaves. Severity varies from few to many leaves showing the spots and leaf-drop on different trees. Similar, but less severe symptoms appear in other varieties that have yellow delicious in their heritage. I suspect it to be a fungal infection, because the spots appear on green leaves, which then turn yellow and drop. Frequent captan plus phosphorous acid sprays have been applied for sooty blotch in recent weeks because of frequent rains and and infrequent appearances of the sun. I have seen similar, but less severe occurrences of the disorder in other years, but would like to hear whether others are seeing it this year, or have knowledge of the causes and prevention. David Kollas Kollas Orchard Connecticut, USA [cid:EA50C707-49A2-4BBA-AC36-0B822B1841AC@hsd1.ct.comcast.net] ___ apple-crop mailing list apple-crop@virtualorchard.com<mailto:apple-crop@virtualorchard.com> http://virtualorchard.net/mailman/listinfo/apple-crop -- Maurice Tougas Tougas Family Farm Northborough,MA 01532 508-450-0844 ___ apple-crop mailing list apple-crop@virtualorchard.com http://virtualorchard.net/mailman/listinfo/apple-crop
Re: [apple-crop-2] Photos of dying trees-fireblight- Doug
I’m not sure if this fire blight or Phytophthora – this problem and the pictures look very familiar to what I’ve been observing the last 5 years in PA (this is my frame of reference since I started in 2013). Another pathogen to keep in mind that is often linked to this sort of mystery tree death/decline is Botryosphaeria spp., either B. dothidea or B. obtusa, – white rot or black rot. However, this pathogen is not THE cause of the decline. These fungi are everywhere and typically don’t create any hassle for the tree: These are relatively weak fungal pathogens and they will not cause tree death when the tree is healthy. They take advantage of weakened, stressed trees – this is when you have tree death. What I have observed is something is going on in the graft union area. We have been isolating Bot pathogens fire blight and Phytophthora have been ruled out. The next question is: what ultimately weakened/stressed the tree to make it susceptible to these weak pathogens. We have been studying this rapid decline problem in PA since 2013ish…and there are (still) more questions than answers, I’m afraid. I wrote about this late 2016: https://extension.psu.edu/apple-disease-rapid-apple-decline-rad-or-sudden-apple-decline-sad There is not much to add to the above other than we discovered a previously undescribed virus. However, we do not know what connection, IF ANY, this virus has to the decline issue. It is very difficult to prove cause and effect with a virus that infects a woody plant; however, we’re trying. I believe the decline issue is a complex of things occurring (Winter injury? Drought? Herbicide? Rootstocks prone to stress (ie M9)?Etc.), not just one issue. Kari Peter, Ph.D. Assistant Research Professor - Tree Fruit Pathology Department of Plant Pathology and Environmental Microbiology Penn State Fruit Research and Extension Center 290 University Dr., P.O. Box 330 Biglerville, PA 17307-0330 Office: 717-677-6116 Ext. 223 Fax: 717-677-4112 E-mail: ka...@psu.edu<https://webmail.psu.edu/webmail/shell.cgi?timestamp=1362517824> Twitter: https://twitter.com/drtreefruit From: apple-crop-boun...@virtualorchard.com [mailto:apple-crop-boun...@virtualorchard.com] On Behalf Of wincowg...@centurylink.net Sent: Sunday, July 22, 2018 10:09 PM To: Apple-crop discussion list Subject: [apple-crop-2] Photos of dying trees-fireblight- Doug Doug-I looked at the photos you attached and the last photo, #22301at the base just above the rootstock- has long verticle cankers (sunken areas in the bark) and verticle cracking in the bark. Combined with the tree colapsing it sure appears to be fireblight. However you also appear to have significant damage to the rootstock just belowe the graft union when you blow the picture up. Its weedy and from the angle cannot see how much is comprimised. I had emailed you a list of questions on this list but I didnt get a response. The purpose was to try and narrow down whats going on. You have had much advice, from many on the list. The main question is what rootstock is your planting on? If is a suceptable stock with a suceptable root then you have double trouble.The fireblight can run right to the root causing tree colapse. With those cankers visible in the lower trunk this looks like what you have. My guidance to growers with this combination, suceptable stock with suceptable root is take the tree(s) out. You also indicated these were in clusters, again sounds like fireblight, the inoculumn moves to the trees next door and take it out. The soil born disease phytophora can cause a similar looking tree colapse, but will not have the cankers in the trunk. Also is is born in the soil water and usually runs down a row if there is any slope. There are many good labs, both univ and private that can id both fireblight and phytophora if the get live tissue samples. You need to confirm what you have so you can plan control programs. I would certain ___ apple-crop mailing list apple-crop@virtualorchard.com http://virtualorchard.net/mailman/listinfo/apple-crop
Re: [apple-crop-2] What to do when fireblight hits tall spindle
Pruning out fire blight this time of year can be tricky depending how much fire blight you are pruning out. Excessive pruning will encourage more shoot growth = more shoot growth means susceptible shoots to fire blight right now especially with conditions favorable for disease. Trees should be hardened off right now meaning new shoot growth should be finished. When this occurs, the bacteria stops moving in the trees and new fire blight incidence should stop. I would highly recommend avoiding doing anything that would encourage new shoot growth right now. If it were me, I would just wait until the dormant period to aggressively remove everything. There is much debate about cleaning pruning shears between cuts. I don’t recommend it because the bacteria can move 3 feet beyond the site of visible infection, so disinfesting is a moot point. Here is my latest article (June 26, 2018) in Penn State Fruit Times about what to do about fire blight now (it’s just below the info about apple scab): https://extension.psu.edu/mid-season-tree-fruit-disease-update And a note: do not spray any streptomycin. Streptomycin is for bloom time only, and after a trauma event, such as hail. Do not spray it beyond these times. If you are concerned about new shoot growth (if this is a new orchard pushing right now), I would recommend Cueva to limit spread of shoot blight. Kari Peter, Ph.D. Assistant Research Professor - Tree Fruit Pathology Department of Plant Pathology and Environmental Microbiology Penn State Fruit Research and Extension Center 290 University Dr., P.O. Box 330 Biglerville, PA 17307-0330 Office: 717-677-6116 Ext. 223 Fax: 717-677-4112 E-mail: ka...@psu.edu<https://webmail.psu.edu/webmail/shell.cgi?timestamp=1362517824> Twitter: https://twitter.com/drtreefruit From: apple-crop-boun...@virtualorchard.com [mailto:apple-crop-boun...@virtualorchard.com] On Behalf Of Hugh Thomas Sent: Thursday, July 19, 2018 1:14 AM To: Apple-crop discussion list Subject: Re: [apple-crop-2] What to do when fireblight hits tall spindle Doug, it's sort of complicated. First, you probably know the bacteria travels from the tip downwards. The idea is to cut well below where the infection has traveled. You can cut away some bark and see where the brown area meets green cambium. I cut pass this point - well past it. I'm guessing I would cut about three times the length of the affected area. For example, if the tip has died back 6 inches, I would remove 18 inches of that limb. This is my gut but but this has worked for me in the past. I don't know the extent of your knowledge, but you need to be careful not to spread the bacteria with your tools and hands. Some people dip their tools in alcohol or Clorox between cuts. I use Clorox wipes on my shears, making sure I use a fresh wipe almost every cut, as the wipe ought to be very wet. On small limbs, say a quarter of an inch or less, I rip the limb off. The big thing is, take action now!! With warm weather you can get a lot of damage. If you burn the limbs, don't let the smoke drift into your orchard - something a guy told me Sent from my iPhone On Jul 18, 2018, at 10:24 PM, "wincowg...@centurylink.net<mailto:wincowg...@centurylink.net>" mailto:wincowg...@centurylink.net>> wrote: Doug- where are you located? What rootstock(s)? What cultivars? How old are the trees in your tall spindle? What was your fireblight control program at bloom? any post bloom program(s) Win On Jul 18, 2018, at 9:26 PM, Doug Nelson mailto:doug.nel...@nelsonmultimedia.com>> wrote: I appear to have fireblight popping up in my orchard. The ipm group tells me to prune all limbs back to central leader and not to do any spraying. What do you do? ___ apple-crop mailing list apple-crop@virtualorchard.com<mailto:apple-crop@virtualorchard.com> http://virtualorchard.net/mailman/listinfo/apple-crop Win Cowgill Apple-Crop Co-Founder Professor Emeritus, Rutgers, the State University Visiting Scholar, UMASS-Amherst CEO- Win Enterprises International, LLC Editor Horticultural News PO Box 143 Baptistown, NJ 08803 Office 908-489-1476 Fax- 908-996-6404 Email: wincowg...@mac.com<mailto:wincowg...@mac.com> www.wincowgill.com<http://www.wincowgill.com> www.virtualorchard.net/<http://www.virtualorchard.net/> http://giselacherry.com/ http://virtualorchard.net/njfruitfocus/index.html http://www.appletesters.net http://nc140.org Twitter @mrsuncrisp<https://twitter.com/mrsuncrisp> ___ apple-crop mailing list apple-crop@virtualorchard.com<mailto:apple-crop@virtualorchard.com> http://virtualorchard.net/mailman/listinfo/apple-crop ___ apple-crop mailing list apple-crop@virtualorchard.com http://virtualorchard.net/mailman/listinfo/apple-crop
