Hi, everyone. Hope it has been a nice spring for you wherever you may be. I come to with a question regarding what may be wrong with a few of my maples this spring. I had several of them begin to leaf out then suddenly every leaf just wilted and drooped, and now it appears these trees may be dead. Each one is in a pot. A quick search on the internet suggested verticillium wilt as a likely culprit but I am unsure. Wet feet shouldn't have been an issue with these trees either. Is there any way I can be sure it is/isn't verticillium? All the best, Kyle
I'm glad you are unsure. Verticillium is the standard panic answer for every evil the befalls maples. There is a multitude of other likely explanations, but I am not going to write a PhD thesis here. Cut through the trunk of your dead tree - either cross-cut or split it; maybe both. Verticillium leaves characteristic blackish stains in the wood. If so and if you mean that they are still in the nursery containers they were in when purchased, you should discuss getting replacements with from your vendor as the verticillium would have to be in the soil in those pots. On the other hand, if you repotted them and didn't use composted soil, it could unwittingly be your fault. Verticillium is common in agricultural areas, but is easily killed by routine composting. The cambium of maples exposed to wind and/or bright sun during winter may die over winter and cause similar results, though usually just the sunny/windy side of the trunk is affected. Pseudomonas syringae will similarly kill the cambium and is, IMHO, a far more common cause of maple death over the winter. If this bacterium is common in your area or if you live near a forest, it may account for the loss of your trees (if you don't find any black-ish stains in their wood). Lastly, and maybe irrelevantly, have any of your neighbors had similar troubles?
Hi Kyle, sorry to hear about this. It does seem a bit unlikely that Verticillium would hit several trees at once. Same for phytophthora, water mold, which can also cause leaf wilt and death. I just had an unknown 2-year old maple experience sudden leaf wilt, and it seems likely it's due to very high greenhouse temps and overwatering (as a result). Hard to know whether it will recover, but it seems probably cooked. So I would look for some environmental factor. Pseudomonas have a peculiar ice nucleating capability, so if it was down near freezing and wet, that could attack several at once. You would see tip die-back and maybe black spots, however. @0soyoung , I though Verticillium was in all garden soil, basically everything but hot compost and sterilized potting soil; just a question of concentration wrt agricultural soil, and esp soil where Solanaceae were grown. Kyle, hope your seeds are sprouting!
Apologies for the delayed response after you two came quickly to my aid! After further inspection I believe the Pseudomonas is the culprit. I actually live in an incredibly rural area, completely surrounded by national forest. And it would appear I lost a good bit to (probably) pseudomonas this winter/spring. Is there anything I can do to prevent this? Or atleast decrease the odds?
Hi Kyle, yes, you can pulverize Bordeaux Mix as a prophylactic treatment, every 4 weeks during winter, and try to keep the pots our of the wet. Here in mudville, without much freezing, I used to see lots of losses when I left pots out. Cheers, -E
I don't think there is Bordeaux Mix here in the states, but it seems like there's some equivalents I can get. Ah, yeah a large portion of my pots were left out in the elements this winter. Should I just bring them on to the carport or another covered area where they can't get too wet but will still have a sufficient cold period?
That's what I do. Bring all pots into an unheated outbuilding. I spray with BM prior to bringing inside, and water lightly a few times over winter. This past winter I left a few out, some were under a tree and did OK, a few were exposed an were none too happy by springtime.
