Axel, I am sure Dave's intent was not to threaten you, only help make us all aware of the requirements of federal law as it pertains to commercial apple growing. We, as professional growers, have an obligation to abide by federal law just as a physician has an obligation to abide by the Hippocratic oath. Yes, we do take our selves very seriously...well, except in the case of leprechauns....because we have to. Right now in Illinois, we are facing a near epidemic with fire blight, which can wipe out a commercial orchard in a matter of weeks. But we can use only properly labeled products to control fire blight and can only apply those products with the proper certification.
In light of our discussion on Fire Blight, we have been able to control an outbreak we had here at Royal Oak Farm back in 2007. We had almost 1,000 trees in a block of 5,000 trees hit by Fire Blight and it took 6 employees 3 days working 10 hours per day to cut it all out. We did not sterilize our chain saws, saws-alls, loppers or pruning shears. In 2008 we sprayed our usual copper at the maximum rate, then at bloom we did our normal orchard wide strep spray at maximum rate followed 5 days later with a Mychoshield spray at maximum rate only in the affected block based on a bloom period of just over 12 days. We then applied Apogee following the standard rate to control growth. This season we followed the same protocol with the dormant copper spray at maximum rate, Strep spray at maximum rate, but since we had an very extended bloom period of almost 3 weeks, we did an additional strep spray orchard wide and the Mychoshield spray only in the block affected by fire Blight in 2007. We have had minimal fire blight this season and have cut out what we have seen immediately after spotting it. Each morning we have an employee drive through each row of our tree rows and prune out any fire blight he sees. So far we have not had any significant branch loss, only minor stem loss. Where we think we failed in 2007 was not doing the second strep spray during bloom. We grow varieties that range from Pristine through Granny Smith so we can see somewhat of an extended bloom period in terms of the range of trees we grow. If lower spring temperatures are added to that, we can see a very extended period as we did this past spring, which happened to be the wettest on record. I won't even bring scab up in this post! Dennis Norton Royal Oak Farm Orchard Office (815) 648-4467 Mobile (815) 228-2174 Fax (609) 228-2174 http://www.royaloakfarmorchard.com http://www.theorchardkeeper.blogspot.com http://www.revivalhymn.com ----- Original Message ----- From: Axel Kratel To: Apple-Crop Sent: Tuesday, July 14, 2009 1:36 PM Subject: Re: Apple-Crop: Fireblight Update Sorry, I meant to say use retromycin sulfate, which is perfectly legal to use on plants, and even has the right EPA label, I just used neosporin as a way to keep the powder on the cuts. I thought neosporin had bactrin in it, apparently it doesn't. It would work equally well with silicon paste or any other pasty substrate. But anyway, I am truly sorry I ever even posted this. If someone isn't even allowed to experiment and have someone on this list threaten with Federal law, well, then so be it, given that this is the second nasty E-mail I got, consider this to be my last post on this list. You people take yourself way too seriously. Good bye. ------------------------------------------------------------------------------ From: Dave Rosenberger <da...@cornell.edu> To: apple-crop@virtualorchard.net Sent: Tuesday, July 14, 2009 10:24:09 AM Subject: Re: Apple-Crop: Fireblight Update I've enjoyed reading the postings and opinions concerning how to manage fire blight in Alex's Ernst Bosch apple tree. Those of us who have worked with or experienced fire blight know that this disease is very difficult to understand and manage. What works on one cultivar, in one year, or in one location may fail to work on another cultivar/year/location and what is cost-effective for one apple grower may be totally implausible in other economic models. Thus, I'm not going to debate Alex's observations. HOWEVER, I feel obligated to point out that within the boundaries of the United States (and I believe that still includes California), application of an antibiotic paste to pruning cuts is a violation of federal law. Any product used in that manner would require a federal pesticide label from EPA. That requirement applies to homeowners and hobby farmers as well as commercial growers. So far as I know, no antibiotic pastes are labeled for use on tree fruits to control fire blight. There are good reasons for these regulations, but I won't take time to discuss them. The bottom line is that using human or veterinary antibiotics on fruit trees or other crop plants is both illegal and potentially dangerous. > I posted a while back on an Ernst Bosch Apple tree that came down with fireblight. I wanted to share with the group what had happened, although I must say that after reading the latest Illinois Fruits and Vegetable Crop news, I am grateful not to have to deal with the fireblight outbreak that the Midwest is experiencing this year. > > We are not in a fireblight prone area due to our cool, dry conditions, but this year, fireblight has broken out in a number of local orchards thanks to a warm and humid, rainy and drizzly week in May. So this has been a learning experience for me. > > I finally figured out how to deal with the fireblight infection, here is what I did: > > Since only one of my 200 trees (of which 80 are apple trees on MM111) came down with fireblight, my focus was to eliminate any further disease vectors, so removal of the tree is the only solution. However, I am a scientist by training, and my curiosity got me to play with the tree for a bit to try to understand what is going on. > > Here are some of the observations: > > Step one was to cut, but to my dismay, the infection returned, even after several cuts. Disinfecting the shears seemed irrelevant. The morning dew collecting on the cuts would often turn orange, and the drops would carry the infection to lower limbs. > > Step two was to try to figure out if the re-infection vector was external, or the bacteria was already systemic in the cambium. So for the next sets of cuts, my approach was to coat the cuts with a oily antibiotic paste with a bactrin base (bactrin is a wide spectrum antibiotic). The coating would prevent re-infection from external sources, but not if the bacteria is systemic in the cambium. Sure enough, another set of cuts lead to more infection, the ooze coming from under the paste. It only took 24 hours for the wood to turn orange under the paste, proof that the infection came from inside the tree, not from external sources or from the pruning sheers. > > Step 3 was to prune back radically, past the node of the infected branch. Upon close inspection, I discovered that the cambium had a darker shade, Cutting into the darker shaded areas revealed healthy wood, but the cut turned orange within 24 hours and would start to ooze. However, cutting several inches below any slightly darkened areas did not cause the wood to turn orange, and no re-infection took place. > > Step 4 was to douse the tree with antibiotic to make sure there is not any residual fireblight bacteria on the tree. I used a combination of bactrin and retromycin sulfate to treat the tree and surrounding mulch. > > At this point, it's safe to say the fireblight active infection is gone, although I believe the bacteria is still in the tree, but dormant for now even though there are no visible cankers. Since the tree is so young, I plan on removing and replacing it after the harvest this October. But before I do, I also plan on feeding the tree some heavy nitrogen to get it to grow and see if the new growth will show signs of re-infection. > > My conclusion for controlling fireblight is the following: the bacteria travels much, much further than 6-12 inches, and one must cut past any infected ambium: Chances are trees could carry fireblight even without showing any active signs of infection. > > 1) Always coat the cuts with an antibiotic oil-based paste to prevent re-infection from outside vectors. > > 2) The wood must be placed into a plastic bag immediately and not allowed to touch anything else. So it's a good idea to cover any oozing branch into a plastic bag and break off the branch, then do the pruning so no ooze droplet hits any other part of the tree. > > 3) Always disinfect the sheers in case the previous cut was into still infected wood. Preferred disinfection is a field heat treatement disinfector, which should be used anyway to prevent any sort of disease spread. You wouldn't want the doctor not to disinfect his surgical instruments before treating you, a plant is no different. > > 4) Always observe for orange discoloration under the paste for the next 24 to 72 hours. If the orange discoloration returns, the cut was made into more infected tissue, and you have to cut further. > > 5) After any infected tissue is removed and discarded, the tree needs to be treated externally with an antibiotic to remove any residual bacteria. > > I cannot vouch that the above would work outside of Santa Cruz county; when I see the pictures of fireblight in the midwest, it makes me wonder how one would even deal with fireblight once it broke out, the only reasonable approach seems radical removal, and preventative spraying in the Spring. -- ************************************************************** Dave Rosenberger Professor of Plant Pathology Office: 845-691-7231 Cornell University's Hudson Valley Lab Fax: 845-691-2719 P.O. Box 727, Highland, NY 12528 Cell: 845-594-3060 http://www.nysaes.cornell.edu/pp/faculty/rosenberger/ -------------------------------------------------------------------------- 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.
