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What's the matter with my oak tree?
I've an oak tree, not mature, about 12-14" thick at the base of
the trunk. Quite a lot of the leaves are going brown - the upper surfaces look normal, except for brown patches of course, but the lower surfaces are covered in patches of "stuff". Imagine a miniature umbrella, open, without the handle, with the spike dug into the underneath of the leaf. Now imagine many of these per leaf, some mature looking browny spots, some new-looking green ones, of smaller size. The diameter of the larger spots must be about 1/6" (just over 4mm). These spots, or scales, are held onto the leaf by the central "spike", and can be levered off with the point of my pen-knife. Here's an attempt at ASCII art, may not come out properly unless you're using a fixed-width font (poss. not even then!): ################################ - leaf __|__ _|_ _|_ - things / \ / \ Mature -- immature brown green The umbrella shape is rather exaggerated. What sort of nasty are these??? Any help much appreciated! |
What's the matter with my oak tree?
http://images.google.com/images?q=oa...=Google+Search
Regards, Emrys Davies. wrote in message ... I've an oak tree, not mature, about 12-14" thick at the base of the trunk. Quite a lot of the leaves are going brown - the upper surfaces look normal, except for brown patches of course, but the lower surfaces are covered in patches of "stuff". Imagine a miniature umbrella, open, without the handle, with the spike dug into the underneath of the leaf. Now imagine many of these per leaf, some mature looking browny spots, some new-looking green ones, of smaller size. The diameter of the larger spots must be about 1/6" (just over 4mm). These spots, or scales, are held onto the leaf by the central "spike", and can be levered off with the point of my pen-knife. Here's an attempt at ASCII art, may not come out properly unless you're using a fixed-width font (poss. not even then!): ################################ - leaf __|__ _|_ _|_ - things / \ / \ Mature -- immature brown green The umbrella shape is rather exaggerated. What sort of nasty are these??? Any help much appreciated! |
What's the matter with my oak tree?
Emrys Davies wrote:
wrote in message ... I've an oak tree, not mature, about 12-14" thick at the base of the trunk. Quite a lot of the leaves are going brown - the upper surfaces look normal, except for brown patches of course, but the lower surfaces are covered in patches of "stuff". Imagine a miniature umbrella, open, without the handle, with the spike dug into the underneath of the leaf. Now imagine many of these per leaf, some mature looking browny spots, some new-looking green ones, of smaller size. The diameter of the larger spots must be about 1/6" (just over 4mm). These spots, or scales, are held onto the leaf by the central "spike", and can be levered off with the point of my pen-knife. Here's an attempt at ASCII art, may not come out properly unless you're using a fixed-width font (poss. not even then!): ################################ - leaf __|__ _|_ _|_ - things / \ / \ Mature -- immature brown green The umbrella shape is rather exaggerated. What sort of nasty are these??? Any help much appreciated! http://images.google.com/images?q=oa...=Google+Search Regards, Emrys Davies. None of those pictures look anything like what is described though. They almost all show oak leaf blister which is doesn't seem to be the OPs problem. I'm curious to see if anyone can identify this rather bizarre sounding gremlin. Thes |
What's the matter with my oak tree?
Thes wrote:
Emrys Davies wrote: deepdigger wrote... I've an oak tree, not mature, about 12-14" thick at the base of the trunk. Quite a lot of the leaves are going brown - the upper surfaces look normal, except for brown patches of course, but the lower surfaces are covered in patches of "stuff". Imagine a miniature umbrella, open, without the handle, with the spike dug into the underneath of the leaf. Now imagine many of these per leaf, some mature looking browny spots, some new-looking green ones, of smaller size. The diameter of the larger spots must be about 1/6" (just over 4mm). These spots, or scales, are held onto the leaf by the central "spike", and can be levered off with the point of my pen-knife. Here's an attempt at ASCII art, may not come out properly unless you're using a fixed-width font (poss. not even then!): ################################ - leaf __|__ _|_ _|_ - things / \ / \ Mature -- immature brown green The umbrella shape is rather exaggerated. What sort of nasty are these??? Any help much appreciated! http://images.google.com/images?q=oa...=Google+Search None of those pictures look anything like what is described though. They almost all show oak leaf blister which is doesn't seem to be the OPs problem. I'm curious to see if anyone can identify this rather bizarre sounding gremlin. Thank you Emrys, Thes - it isn't oak leaf blister, these things are like a somewhat concave disc on a little stalk which attaches to the leaf. Break the stalk and the disc pops off. They are quite closely-spaced on some leaves, which are going brown. |
What's the matter with my oak tree?
wrote in message .. .
Imagine a miniature umbrella, open, without the handle, with the spike dug into the underneath of the leaf. What about The smooth spangle gall http://www.bioimages.org.uk/HTML/P30131.HTM They are all caused by gall wasps, some almost invisbly small. |
What's the matter with my oak tree?
Oh I say. Thank you very much. It seems to be the common spangle
gall, with some of Mr. Harvey's smooth spangle gall, which I mistook for "immature galls". Fascinating stuff, there's some information at: http://www.btinternet.com/~arb_excha...d_spangle.html with a link to the "currant galls" which are part of the life-cycle of the wasp earlier in the year. Concise information and well worth a glance! Thanks again. |
What's the matter with my oak tree?
wrote:
Oh I say. Thank you very much. It seems to be the common spangle gall, with some of Mr. Harvey's smooth spangle gall, which I mistook for "immature galls". Fascinating stuff, Isn't it. My oak has the common and silk spangles every year, and occasionally this one: http://www.bioimages.org.uk/HTML/P45254.HTM and over half our acorns have Knopper galls http://www.bioimages.org.uk/HTML/P30118.HTM http://www.kulak.ac.be/facult/wet/biologie/pb/kulakbiocampus/gallen/pagina's/eik-knoppergal2-Andricus%20quercuscalicis.htm although they look more like the picture he http://www.gwydir.demon.co.uk/insects/cynipidae.htm On that last page is a robin's pin cushion - we have that on a wild rose this year for the first time I can remember since moving here. I suspect the 'robin' in question might be robin goodfellow. What do you think? |
What's the matter with my oak tree?
On 13 Aug 2004 10:13:28 -0000,
wrote: Oh I say. Thank you very much. It seems to be the common spangle gall, with some of Mr. Harvey's smooth spangle gall, which I mistook for "immature galls". Fascinating stuff, It's worth adding that these things are practically never seriously damaging - just interesting - slightly disfiguring at worst ================================================= Rod Weed my email address to reply. http://website.lineone.net/~rodcraddock/index.html |
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