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#1
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(IBC) cryptomeria blight
Les said:
can anybody advise me re my ailing cryptomeria (Jindai sugi). Various branches turning reddish brown, seems to have stopped taking up water from the soil. I have moved it to a shady spot and stopped watering it. Still misting it, though, and I have sprayed it with a sulphur based fungicide on the suspicion that this is the infamous cryptomeria blight I have read about. I say: Les, is this plant outdoors? I only ask because you say you are misting it, and I can't imagine why anyone would mist an outdoor tree. At any rate, if you *do* have cryptomeria blight, misting is the worst possible idea- the disease spreads in water droplets, and everyone universally advises good air circulation to control this problem. Look at the diseased foliage and twigs for little embedded black spots; that's the key sign of the disease. If it's clear that the tree has blight, sulfur fungicide is OK, but I'd stop misting, and prune the tree to remove diseased foliage (sterilize the tool between cuts with 70% alcohol or 10% bleach, and certainly sterilize before using on any other conifer!). If weather is rainy, I'd provide shelter during storms to keep the needles dry. Obviously, if the plant is indoors, being indoors is the problem, not blight. Cryptomeria will not survive indoors unless you have a good set-up for it. Nina Shishkoff |
#2
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Sorry to be so long getting back to the group on this. I put the
question up without considering that I would be unable to get to a computer for the next day and a half. I'm going to have to invoke the "I'm-still-kind-of-new-at-this" clause in my defence. Marty; I am beginning to wonder if you are not right on the money. After reading Nina's response (see reply below) I wonder if I might, as you suspect, really be dealing with a root problem. Nina; I really appreciate someone with your level of expertise taking the time to advise me. In answer to your questions.. Yes, the tree is outdoors. I am misting an outdoor tree because Tomlinson (The Complete Book of Bonsai, page 116) says, "Water generously once a day and mist-spray foliage daily during the summer months." Adams (Bonsai Design: Deciduous and Coniferous Trees, page 47, in the chapter devoted to junipers and cryptomeria) says, "Central to the robust health of Junipers, is daily foliar misting, which supplies the 'cloud cover' so appreciated by this species. this also applies to Cryptomeria." Lewis (Bonsai: A Care Manual, page 87) says, "Cryptomeria inhabit the lower slopes of mountains where they are shrouded in mist in the morning and exposed to the sun for the rest of the day. Provided you can ensure that the pot will not dry out through evaporation, and you can spray the foliage two or three times a day, your cryptomeria will do well in full sun." Air circulation is pretty good, even in the semi-shaded spot I have move the tree to. Black spots? This is new and useful info. A search with a magnifying lens reveals no little black spots. Perhaps this is not blight, after all. The tree is under cover so even if it did rain here (weather has been unusually warm and dry) it would not get wet. While checking the Colin Lewis reference, I noticed a paragraph about how spider mites love cryptomeria, but I can't see them. Should I spray with an insecticide just in case? The browning of the needles is scattered over the whole tree. It does not begin at the ends of the branches and work its way in the way it did with our blighted garden pyracanthas earlier this year. I have been cutting back where I can, disinfecting tools with bleach as I go. Thanks again for your help. Any new ideas gratefully recieved. Les Linfoot New Westminster, BC, Canada Zone 8 |
#3
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Sorry to be so long getting back to the group on this. I put the
question up without considering that I would be unable to get to a computer for the next day and a half. I'm going to have to invoke the "I'm-still-kind-of-new-at-this" clause in my defence. Marty; I am beginning to wonder if you are not right on the money. After reading Nina's response (see reply below) I wonder if I might, as you suspect, really be dealing with a root problem. Nina; I really appreciate someone with your level of expertise taking the time to advise me. In answer to your questions.. Yes, the tree is outdoors. I am misting an outdoor tree because Tomlinson (The Complete Book of Bonsai, page 116) says, "Water generously once a day and mist-spray foliage daily during the summer months." Adams (Bonsai Design: Deciduous and Coniferous Trees, page 47, in the chapter devoted to junipers and cryptomeria) says, "Central to the robust health of Junipers, is daily foliar misting, which supplies the 'cloud cover' so appreciated by this species. this also applies to Cryptomeria." Lewis (Bonsai: A Care Manual, page 87) says, "Cryptomeria inhabit the lower slopes of mountains where they are shrouded in mist in the morning and exposed to the sun for the rest of the day. Provided you can ensure that the pot will not dry out through evaporation, and you can spray the foliage two or three times a day, your cryptomeria will do well in full sun." Air circulation is pretty good, even in the semi-shaded spot I have move the tree to. Black spots? This is new and useful info. A search with a magnifying lens reveals no little black spots. Perhaps this is not blight, after all. The tree is under cover so even if it did rain here (weather has been unusually warm and dry) it would not get wet. While checking the Colin Lewis reference, I noticed a paragraph about how spider mites love cryptomeria, but I can't see them. Should I spray with an insecticide just in case? The browning of the needles is scattered over the whole tree. It does not begin at the ends of the branches and work its way in the way it did with our blighted garden pyracanthas earlier this year. I have been cutting back where I can, disinfecting tools with bleach as I go. Thanks again for your help. Any new ideas gratefully recieved. Les Linfoot New Westminster, BC, Canada Zone 8 |
#4
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Les linfoot wrote in message .. .
I am misting an outdoor tree because Tomlinson (The Complete Book of Bonsai, page 116) says, "Water generously once a day and mist-spray foliage daily during the summer months." Adams (Bonsai Design: Deciduous and Coniferous Trees, page 47, in the chapter devoted to junipers and cryptomeria) says, "Central to the robust health of Junipers, is daily foliar misting, which supplies the 'cloud cover' so appreciated by this species. this also applies to Cryptomeria." Lewis (Bonsai: A Care Manual, page 87) says, "Cryptomeria inhabit the lower slopes of mountains where they are shrouded in mist in the morning and exposed to the sun for the rest of the day. Provided you can ensure that the pot will not dry out through evaporation, and you can spray the foliage two or three times a day, your cryptomeria will do well in full sun." Well, honestly, that all sounds like nonsense to me. I have never misted a juniper in my life. If you live in a dry climate, no amount of misting is going to create a "cloud cover". And if you live in a humid place, misting isn't going to add appreciable humidity. Cryptomerias are trees of the lower canopy of forests, so the best way to give them the conditions they require is to give them some shade. Treat them as you would a Japanese maple. However, of all tree used in bonsai, cryptomeria can have the densest foliage, so misting (or keeping it in the shade, or sheltering it from wind) can increase the number of hours of leaf moisture inside the foliage pads. As a plant pathologist, I see this as only a bad thing; it fosters fungi. I always trim my trees to avoid pockets of thick foliage. On this list, the most commonly reported problem of cryptomeria is inner browning of the foliage, which is generally attributed to lack of sunlight penetrating through all that thick foliage. The solution is to thin the foliage. Your problem is not inner browning, but, according to your description, a browning of whole branches. You might want to go to a nursery with cryptomerias and observe a whole bunch of them to make sure this isn't natural-- I have a cultivar of Chamaecyparis thyoides ('Little Jamie') that normally loses its lower branches, so I don't even worry about it any more. You might, as Marty suggested, have a root problem. I'm fearless when it comes to roots (I did my PhD on root anatomy!), so if I were you, I'd water the tree like normal, then I'd carefully pull the tree out of the pot and poke around. I'd be worried about pockets of soil that for some reason or other do not get wet; this is a real problem of trees grown in soil and transplanted to pots later; often a core of clay resists wetting, and roots within that core die. Overwatering can also be a problem, but rarely in outdoor bonsai in good soil. If your soil is heavy, and smells rank and "anaerobic", it may be water-logged. Look for obviously dead roots. If you know what healthy roots look like, look for roots that are darker or slimier. Healthy juniper roots are brown and flexible, with tips that are plump and reddish. If you see dead roots, remove them. If the problem is serious and you have to transplant, transplant into coarse sand or pure turface and hope for the best. Otherwise, correct the under- or over-watering problem and wait for the tree to recover. Nina. The hurricane passed tranquilly over us, giving us a gentle rain. |
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