I have a Japanese red emperor I bought and planted this year. the problem I'm having is all of the leaves have brown holes throughout them as well as some wilting. I have mulch around the base and water it daily. I have looked the tree over for signs of insects that might be eating them but so far I haven't found any. I live in Tn and it's been in the mid to high 90's consistantly this summer. I have not fertilized with anything to date.
It would help to see a photograph of the brown holes and wilting, as well as any discolored bark. The weather has been a problem for so many this year, but brown holes may suggest something else.
here are some pics I took of some of the leaves. I guess the more up close I look at then, the more it looks like something has been eating the leaves, although I check continuously and have never seen anything on them. Also in pic #2 & #3, some of the leaves are green, which I have never noticed before. thanks
How many hours of sun is this tree getting and for what portion of the day (e.g. morning, evening, etc.)? And, how long ago did you plant it?
it gets the afternoon sun, probably 4-6 hrs. I planted it about 5 months ago, it was (and is) around 6ft tall.
Here on the forum many of us are just learning more about the details of pests and diseases of Japanese maples, but the holes in the leaves do not, at first glance, look to be those described as due to various leaf spot fungi. Nor do they look to be due to culture, although some of the damage looks like what one can see when the leaves are rubbed against another surface or blown by the wind against another plant with prickles. “Leaves are again the target of several groups of other insects, including ‘worms.’ Wasps, bees, and beetles (such as the Japanese beetle), which chew holes in the leaves around the edges. However, the larvae of certain moths and butterflies – the ‘worms’ or caterpillars (order Lepidoptera) – do most of this kind of damage. Examples are the fall cankerworm, green-striped maple worm, and the maple-leaf cutter.” Vertrees and Gregory, Japanese Maples 3rd Ed. (Timber Press 2001). I assume that you are patrolling for insects during the day. If so, also patrol with a flashlight at night, as late as you can, and check on the undersides of the leaves. It is difficult to find any good photographs online of various insects’ damage to Japanese maple leaves, but there is at least one photograph of a Japanese beetle making isolated holes such as what you are seeing. Typically, the Japanese beetle makes a lace-leaf pattern or totally munches portions of the leaf away. “Plants particularly at risk to Japanese beetle feeding include those that have recently been transplanted or those that are stressed for one reason or another.” http://www.ppdl.org/dd/id/japanese_beetles.html. “The adults are most active in the afternoon in full sun.” http://wihort.uwex.edu/gardenfacts/X1062.pdf. For a photograph of what the damage from Japanese beetles can look like on a red-leaf Japanese maple, check out: http://www.tennessean.com/apps/pbcs.dll/article?AID=/20060722/FEATURES0302/607220302/1407. In another thread, Dixie mentioned that if Japanese beetles are present, then one will see numbers of them. They definitely are a presence in Tennessee, if not in your garden, and know that it may be a problem in the future, since Japanese maple is a preferred food. If you could take these photographs and a few leaves to your local extension office, they may know more about what critters are actively chomping on foliage now, and let us know if they have any information, since it seems to be difficult to find online. If you have any other plants with similar damage in the garden, that is really helpful information since critters have their favorite plants; it helps with identification. Finally, it is not clear to me what is going on in the photograph with the patterned branch. If you could add a close-up photograph of that part of the branch, it may provide a little more information about a particular critter, because some enter the top layer, lay eggs, which then hatch, start making their way through tissue, etc. The critter could have come in with the plant in March, but when did you start noticing the problem with the leaves?
here is an up close picture of the bark on the trunk. it looks like there is some "splitting" throughout the tree, it's on the trunk as well as the branches. I have regularly been checking the tree in the day time and found not found 1 insect on it. i'm going to check for the next couple of nights to see if anything is feeding at night.
Thank-you for the additional photograph. You need not look for the responsible critter now unless there is continuing damage to the leaves. The leaf damage looks similar to some of what I am seeing in some of our maples of other species, and which I really believe is due to pests, two of which I have seen, but have yet to identify. I will let you know when I do. Unfortunately, I am sorry to say that I think you have a far more serious issue with the bark of this tree, which clearly is not the typical healthy bark of Acer palmatum, and was surely present when you purchased it. This morning I paged through Sinclair, Diseases of Trees and Shrubs 2nd Ed. (Cornell 2005). The photographs that looked closest to what we see here (in the oval split areas) were in the sections on 1) canker caused by Botryosphaeria stevensii, anamorph Diplodia mutila; and 2) damage by hail, ice glaze, and sheet ice. The tree could have come to the nursery from colder areas last season, since the latter issue is rather rare in Tennessee, and photographs of the former issue in maples are really difficult to find online. A. palmatum is susceptible to stem canker. http://www.mobot.org/gardeninghelp/plantfinder/Plant.asp?code=B974. To get a general idea of what canker can look like, a photograph of Nectria canker on sugar maple is at http://www.ipm.uiuc.edu/diseases/series600/rpd636/index.html. It is my humble opinion that this tree is not at its healthiest and is really at risk for infection by "opportunistic pathogens." It would be really great if you could get a diagnosis from the extension for the bark issue. Then the nursery you purchased it from should exchange it for a healthy specimen.
Absolutely excellent post. I lost a Bloodgood 5 years ago to canker. The previous season 80 percent of my yard was attacked by aphids. The tree got sick the following year or season. one third of the crown failed to leaf out and eventually turned brown An arborist cut the top off but the tree could not survive the stress. He diagnosed CANKER! Very stressful experience. I now am in a different location and risked planting 4 JM of various cultivation. They get wind and when it is strong I cringe, smile I am crossing my fingers they survive. With this excellent article I may have a bit better chance at recognizing this nasty condition earlier. My tree at its peak at back rt Little one in front.
