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  • From: "Kieran &/or Donna" <holycow@frontiernet.net>
  • To: <nottke1@earthlink.net>
  • Cc: North American Fruit Explorers <nafex@lists.ibiblio.org>
  • Subject: [NAFEX] Fw: Pear Rust
  • Date: Fri, 5 Jun 2009 12:17:12 -0500

Jim,
It seems no one else has any thoughts on this subject. So here is what I do know about it. You may be looking at any of several rusts and only think it is PCR. CAR grows for a year on cedars which have to be re-infected annually to keep the disease going. There are two others I haven't sorted out yet, one makes the same sort of balls on cedars but smaller. The other, which I think is quince rust, makes lesions on cedar trunks and branches. This one lasts for years on cedars and can cause serious damage to the cedar. (oops, translate juniper) I had never noticed it before but after last year's severe rust on a chestnut crab I discovered that simply selecting CAR resistant apples is not sufficient. There are so many species of this sort of cedar- rose family rust that apples, pears, hawthorns, quince and juneberries all need to be taken into account as well as the juniper host plants. Most of the infection is on the haw, quince and juneberry fruits, if you are inspecting them. You'll have to look up specific symptoms for each to sort them out. On the cedars, wait for rainy damp weather and inspect for infection. Cut out the little balls and consider removing at least the worst infected trees. The bad one is the quince (I think) rust on the cedar trunks. I found one small tree with a little bitty new infection. A section of trunk about the diameter and length of my finger was sprouting little orange dots. then I found a tree with a 2" dbh trunk that had a lesion as long as my arm down the trunk oozing great wads of orange goo. THEN I found a 6" dbh tree in the woods with orange goo oozing at the base of the trunk. At least it was low to the ground and pretty far from any of my fruit trees.
You see how serious this problem can be, which is why we are advised to eliminate all cedars from our property if we want go grow fruit. For me, that is impossible. Not only would my husband object VERY strenously, but there are large junipers right on the edge of the neighboring property that plainly can drop any spores they like right down on some of my trees. Plus junipers are a major part of our winter landscape and pleasure that time of year. So while I was researching the subject with mounting horror last winter, I discovered that tangled up in my search results were lists of resistant junipers. Most of the ones tested are older vars that are no longer trendy in the nursery trade and hard to find. I was lucky that I called an old TTU prof about the 3 clones of cedars on Tech property and he told me they were Keetleri (resistant) and Canerti (infested, as was plain to see). The lovely new clone Gray Owl has proved resistant. And it seems that junipers are really easy to graft, and different species graft just fine on our native trees. So though I was late getting started, it appears I got over 50% takes and learned that the recommended veneer graft is indeed the best way to graft junipers. I hope to "collect the whole set" by next Feb even if it requires a trip over the mtns to the Raulston Arboretum where many the fine juniper clones collected by Raulston are on display. (Oh, I can just imagine how much suffering such a trip will cause, a terrible rash of tree envy that will only be mildly assuaged by much more planting and grafting.)
My idea is to veneer graft near the base of reasonably small cedars on the property, say 2" or 3" at the base. I'm thinking about spiraling grafts up the trunk on some of the larger trees. After a year or so I can start removing the existing tops and with time the larger ungrafted trees. Instead of impoverishing our winter landscape, I can enhance it with colors and shapes that citified landscape freaks would die for. And all very cheaply.
Any of you who think I am silly, make yourself a note to look for newer plantings of a beautiful low cedar that is brilliant blue gray. And start looking more closely at junipers in your area this winter. There is so much variation in form, it's quite interesting. When I went to cut some branches on the 40 year old Keetleri trees at Tech, the more I looked the more I felt terrible for cutting anything off at all. Every branch, every branchlet looked like a whole series of bonsai trees. They were indescribably beautiful. Fractals, phi ratios, Fibonacci series..... I was utterly smitten. They look very nice from a distance too. Donna




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