Hi David, those were very informative results. Seems you do have a problem. I guess what they recommend for destroying are the severely infected plants and parts, just to try to get rid of the bulk of the botrytis blight or "grey mold". And then try to cure the rest with fungicides. Cleary's 3336 wp is a fungicide, it's a wettable powder, toxic and probably not that nice to work with, I've never even heard of it up here in Canada. You may want to search a little at a garden centre for something in a liquid form that controls Anthracnose, as it will most likely control mold too. On the pesticide label there is a Guarentee: "Thiophanate-methyl", is what Cleary's 3336's active ingredient is. You may find that on another label at a garden centre, under a different name even, then you know you got the right fungicide suggested. By the way copper is also effective against both fungus detected. Phytophthora would be a root rot, and was not detected on your samples, a good thing. I'm sure if you were to destroy the very sick Maples and start a proper spraying campain, since there nicely repotted now, you may have some great success. Beware when spraying not to burn your plants in the summer. My suggestion would be to keep the Maples shaded, well watered, and spray in the evening lightly at absolutely no more than the label rates. Most fungicides are toxic to bee's and fish. Jim.
the cleary's is a professional product. you might have some trouble finding it if you don't have access to professional growers products. It is an all-purpose fungicide that treats many different things. It is even labeled for use on turf for brown patch. We always used it for powdery mildew on crepemyrtles. It is one of the best you can get at a good price. You won't be able to get that specific one at a home/garden store, maybe at a farmer's coop though, maybe.
This report is so helpful, so thank-you for sharing it with us; and a thank-you to the clinic as well. First, notice that Botrytis cinerea is your main problem here, and can affect some 200 other species of plants. There is no doubt that you will threatened with this in times to come because of your climate. It is not likely to be the problem that it is this year because the plants were so close together and were apparently stressed from issues related to the soil and water. Cornell University has an excellent web page on Botrytis cinerea: http://plantclinic.cornell.edu/FactSheets/botrytis/botrytis_blight.htm. I would carefully read through that. Then note that New York has a climate that differs from North Carolina, so two other websites from the University of Georgia are helpful regarding Botrytis cinerea: http://www.plant.uga.edu/Extension/news/OrnTree/GerBotBt.html; and http://www.ent.uga.edu/pmh/Horticultural_Crops/Woody_Ornamentals/Ornamentals_Disease_Control-B.htm. What we find here is that mancozeb and Cleary 3336, which in Georgia is apparently readily available to the homeowner, are both recommended for Botrytis cineara and anthracnose - Colletotrichum gloesporioides. Daconil Ultrex can be substituted if Cleary 3336 is too difficult to find. Armed with all of the information in this thread, I made a phone call to my favorite Master Gardener and Consulting Rosarian, whom I trust and who volunteers in the plant diagnostics lab at UWBG. He recommends beginning the spray program now, alternating between mancozeb (trade names Fore, Dithane, and others) and Cleary 3336, broad spectrum and narrow spectrum fungicides, respectively, and both wettable powders (WP). We always recommend a mask, goggles, and clothes that will be changed for a spray program as well - the mask especially when mixing the powder. It seems that the fungicides are EPA toxicity category IV and III, respectively, with I being the most toxic to humans. For the fish, bees, and birds, yes, spray when there is absolutely no wind and evening is fine. I must note that when I sprayed with mancozeb some years ago, it did leave a powdery residue, but it is necessary. Also spray the undersides of the leaves. I asked about copper, and he did not recommend it because of the difference in climates between the Pacific Northwest and North Carolina. I asked about the soil, and fortunately the soil in all your newly planted one-gallons will not harbor the spores, so remove the badly affected plants and immediately place them in a paper bag, which will later be sealed for destruction or disposal, and the soil will be safe to reuse for potting. There are two options for the plants that are showing new growth, but that are not “badly” affected: destroy them, as this fungus moves quickly through these and on to other plants; or remove the affected leaves, and move these affected plants to a “quarantine” area on your property. Then you can monitor the success of your spray program to bring this under control. When I thought that this could be fungal disease, it was my experience growing roses that led to the recommendations above, as roses are notorious for powdery mildew and blackspot – two fungal diseases. Otherwise I have not dealt with the extent of a problem that you currently have. I still see a similarity though, because we recommend watering roses from below and spacing them adequately. I hand-water all of my maples from below as well. I isolate diseased roses because powdery mildew is wind-born; in fact, nothing remains on the property that gets powdery mildew. My friend keeps an indicator rose, which is known to be more susceptible to blackspot, as a measure of times to spray, as well as watching the weather reports for humidity and rain (because blackspot needs seven hours of standing water to reproduce). You will need to be on top of the weather reports next spring because these articles give a strong indicator that when the humidity is high and the temperatures get to 60F in spring, then Botrytis is going to reproduce and be problematic. You will need to spray shortly before these conditions are present as advised given this season’s Botrytis problem.
when we talk about removing damaged leaves are we talking about brown buds an brown leaves just under the buds ok all brown leaves or are we talking about mature green leaves with a powdery looking mold growing on them that easyly wipes right off ?
Definately any leaves, buds, or wood that has started to decay or rot from mold. I'm sure there is probably a dusty mold on a lot of areas, I would just you use your best judgement, what looks fairly healthy keep. Whats definately and seriously infected, toss. Also any leaves that show a lot of wilting and browning from the anthracnose should probably be picked off and disposed off too. Personally I would try to save as much as possible, I've done a lot of fungicide spraying for many years, having some faith in your products and efforts will go a long way. Laurie sure did her homework for you, that was well done Laurie. As for Copper, my expierence is strickly on the west coast, and really don't know whats availible and most effective in the east, it is likely the most effective here though, and never seem to get a resistance build up. But , I can tell you from my expierence that daconil is extremely effective and considered very low in toxicity to humans, with a LD50 over 10,000, and is also in a liquid form, although resistance builds up fast, even afer 3-4 applications. To boast on Laurie's comment, over head watering in the evening is likely the largest cause of the spread of Blight. Water in the morning or daytime so the sun can dry off your plants. Well thats my 2 cents anyway. Jim.
i removed all the dead dried up leaves an buds about 2 weeks ago at that time there was very little mold on green leaves i repoted to gallon pots an been giving them plenty of water right before dark now i have mold on allmost all of the green leaves i dont have hardly any more dried up leaves an some have started new growth again i got a long wand to water with so as not to get the leaves wet i will dispose of a few reel bad molded plants an go get some 3336 tommorow i called an found some today i will change my watering to mornings instead of evenings my next question is do i need to go ahead an spray (lightly) all my grafted plants also at this time ? i have one grafted tree that looks to have the anthracnose thanks to everyone that has posted an helped me out with my trees an yes laura has really done her homework trying to help me save my trees an for that a special thanks laura david in nc
As sanitation is one of the major aspects of a maintenance program and this is just now being implemented in your garden in its complex details, I would think it advisable to spray all of the maples of concern, even if no symptoms are visible. When you wiped the powdery looking mold off the leaves, you were spreading the spores in whichever direction the winds were blowing, and you had spores on your hands or gloves, jacket, etc. If you went to inspect your grafted trees for signs before cleaning up, you could have spread spores onto those trees, even if they are in a different part of the garden. Perhaps it would be good idea to have a separate pair of well-differentiated gloves to attend to the infected plants. You need to follow the instructions on the label for mixing the fungicide solution and for number of days between sprayings. We neither spray lightly nor drench the plant, but rather just make sure to cover the tops and bottoms of the leaves, as well as the stem for Botrytis. Jims comment about how quickly fungus can build up a resistance to Daconil (which, incidentally, is effective for blackspot on roses) is the reason that my friend recommends a rotating program to include mancozeb as well because of how broad spectrum and narrow spectrum fungicides work. Follow the instructions for recommendations for number of days between applications for each product, even if they are different. I would like to note that I recall that the solubility of mancozeb was better in warmer water; really mix the solution so that the powder goes into solution, it seems that it was stubborn. Thank-you for remarking on the time it sometimes takes to prepare an informative entry from which we all learn. For example, I did not know that damage to leaves from over-watering and under-watering does at times look the same. And that web page on Botrytis at Cornell is wonderful.
well i sure learned one thing from all this, 85 degrees misquitoes an biting yellow flyies at the edge of dark is no fun next year when it's 55 out an the weatherman's 3 day outlook is calling for 60 degrees i'll be all over this !!!!! i picked all the bad looking leaves again wasent many at all and i even picked some green leaves with mold and all my trees got mancozeb this afternoon in 7-10 days i'll give them some 3336 i got the liquid form of both chemicals. david in nc
Hi dmaaero, One thing to keep in mind is, "an ounce of prevention is better than a pound of cure". Being seedlings there is a certain amount of cullage that will happen. They may have or may not have been diseased before you got them. But, regardless of that their lack of proper water most likely contributed to their lack of health and the onset of disease. A healthy plant will be able to fend off most disease attacks. Often it is easy to blame a disease for the plant's demise when we really have to look at our watering/fertilizer regimen and soil culture as a means to prevent disease. Just a thought, Layne
You have received some good information. I have been growing Acer palmatum for over 20 years in the Northwest. Acer palmatum and japonicum especially like to be on the dry side, rather than wet. Some cultivars really need less moisture than others. The number one killer of Japanese maples is wet feet - poor drainage; and even in a container constant rain or watering can drown the roots. Put the affected maples into a dry area - a greenhouse for example and spray with a fungicide and remove the dying leaves. Mother nature should reward you with new leaves in about 4 weeks. Sam-Eastfork Nursery
