I noticed a spot on one of the leaves of my Golden Full Moon. It just appeared within the last 2-3 days. I have no idea what caused it and would sincerely appreciate any help as to identifying what may have caused it and what I should do? It's just on one leaf and it's one of the bigger leaves near the bottom of the plant. Thanks in advance for your reply and assistance!
Had any breaks in the afternoon fogs lately? Like many other yellowleaf variants of garden plants this one will scorch if not protected from hot sun. Can't gaurantee this one spot is an exmaple of sunscorch, but...
Hi Oscar, the leaf is horizontal but i have a drip system where water is dripped at the bottom of the plant instead of spray over the plant so i doubt there could be a drop of water sitting on it but it is still a possibility. would a sitting drop of water cause a spot like that? Thanks!
Do you think it can be due to burn/scorching since it's just on one of the leaves, not on any other leaves?
To me there would be 3 obvious causes of a spot like that, 1 fungal leaf spot (usually grey in the middle with a darker almost black ring around and finally a yellow green ring around the outside) 2 Damage to the leaf before it opened (a sap sucking insect makes a small hole and damages the tissue, when the leaf opens and expands the damage becomes more obvious usually a hole appears and gets bigger) 3 A water droplet sitting in the same place focusing the suns rays and burning the leaf surface (this is where Ron and i have a slight difference of opinion, although thats fine with me, we are all here to learn). There could be other causes, but i cant think of any at the moment.
it doesn't look like 1) a fungal spot and it's not 2) since as of last Saturday, the spot was not there, i have taken pictures of the plant on that day and it was a perfect leaf. Number 3 could still be a possibility but if the scorching/sun burn was not due to a sitting droplet, usually the burning/scorching would start at the edges or the newly sprouted leaves, correct?
I would agree with Ron on this. This is a site that I picked up on from one of his previous posts: http://www.puyallup.wsu.edu/~Linda Chalker-Scott/Horticultural Myths_files/Myths/Leaf scorch.pdf Although I would still be open to the possibility of water burn, I'd have to hear or see some scientific evidence for it to believe it. It might make for a good debate topic.
i have read all that before, you cant tell me one spot on one leaf, in an area where its possible for water to sit could in all probability not be focused sun rays....
It seems logical to me that it could damage the leaf, especially on delicate plants. I just haven't seen any evidence to support the theory. To tell the truth, I haven't seen any solid evidence that water and sunlight can't damage leaves either. It seems that most specialists feel that water could not reflect sunrays to damage leaves, but I would love to see more specific information as to why or why not. I'm still open to having my mind changed on this subject.
Thanks for all the replies. This is probably some sort of sun damage and not due to any pests or diseases? I was just worried that it was due to something other than the sun. If it's caused by the sun, I can keep an eye on it and if more spots occur or if the spot grows larger, I will move the plant (since it's in a pot). I will also make sure i don't get any water on any of the leaves. I just didn't think it was a sunburn since the spot is in the middle of a fully opened leaf instead of the edge or on a newly sprouted leaf.
Sorry to go off topic on your thread. Regardless of the cause, one spot on one leaf is probably not too significant and could be caused by a number of different factors that may be virtually indistinguishable by the one spot. As long as no further damage is detected, I wouldn't be too concerned.
Lplant, agreed, more specific information is required Good science is based on theory, experiment and then conclusion.....i cant see any experimental data (maybe im missing it in there somewhere). One experiment would be to have a sterile plant in a sterile environment (no fungus present), growing in a sterile medium, with no fertilizer and using a drop of pure water.....that would satisfy me. Quote linda "anecdotal evidence that seem to support a cause and effect relationship between midday watering and leaf die back" We are not talking about leaf die back we are talking a small area of damage.
No problem on going "off topic". We are all here for the same reason, to share knowledge and information on Maples so any discussion pertaining to Maples is appreciated. Thanks for the reassurance on the spot and I will keep everyone posted.
Sorry Shishi, went slightly off topic a bit, keep an eye on the plant, post back here if more spots appear. lol, dont type so fast my post should have been before yours :D
From http://www.extension.umn.edu/yardandgarden/ygbriefs/p414anthracnosemaple.html: Symptoms of anthracnose (Discula sp.) include light brown, purple, or black spots that vary in size and shape. On sugar maple, spots are light brown with darker margins, whereas spots on Norway maple are purplish in color. Spots can develop anywhere on the leaf surface and are not restricted by veins. … These fungi overwinter on leaves and twigs that were infected the preceding year. Extended periods of cool, moist weather in May favor a high incidence of fungal leaf spot diseases. Infection is most severe in the lower third of the tree, where the relative humidity remains higher, and on newly emerging leaves. See also: http://hgic.clemson.edu/factsheets/HGIC2005.htm. If there are tiny dots on the back side, it seems, of the leaf within that brown spot, I would remove the leaf. One year I experienced anthracnose, most seriously on Acer pseudosiebodianum ssp. takesimense. The following spring I sprayed the emerging leaves with mancozeb and have not had a problem since. Otherwise, as Ron mentioned and as Vertrees has written, this particular cultivar is quite susceptible to scorching. Therefore, if this specimen is in a pot, I would move it to a shadier spot. Otherwise you may see more of the same through the season, which will be entirely disappointing. It will not kill the tree, but it will surely be detrimental to the summer and fall display.
Thanks for the link to the articles, Laurie. From what i can see, it doesn't look like fungus. i am a newbie when it comes to JM and i didn't know scorching can occur from the middle of the leaf. I thought it would occur from the outer edges first so that's the reason I posted a pic just so i can confirm in case it's not from scorching. The Aureum is in a pot so i will move it and see how it does. Thanks again for all the reply and help!
