Linden loses leaves ~ help!

miloe

Just joined and desparate for help! My 25-30 year old Linden loses 1/4 to 1/3 of its foliage every spring (early June) for the past 3 years. The tree is lush and appears in good health however midway down the stems of the affected leaves, there appears to be a dark pinched area ~ please see photo. By definition, it seems to present itself as the Maple Petiole Borer ... on a Linden? It seems to be 'contagious' as 2 other Lindens in a direct line from ours have now been affected. Would sooo much appreciate an answer!

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TreeSpecialist

My first thought,because you were in Canada and the problem looked close to a driveway, was a problem with salt.

However, the close up of the leaves show a puncture mark in the petiole and your diagnosis of the a maple petiole borer (Caulocampus acericaulis - a type of sawfly) is likely correct.

Tough to control without the use of a systemic insecticide. (Imidicloprid, Abamectin, etc.) Timing of an injectable would be crucial as well to do any good.

Raking and disposing of the leaves, while on the surface sounds like a good way to minimize re-infestation, doesn't work all that well as the larva doing the damage remains in the tree.

Getting an insecticide in or on the tree at the right moment is close to impossible. Since the larva eventually falls to the ground and spends the rest of the year there before emerging as an adult the following spring to repeat the cycle, you might want to try something else.

An "organic" method of controlling ground dwelling larva of various types is to introduce milky spore bacteria (Bacillus popilliae) into the yard.

Beneficial nematodes are another tack to consider. While I'm uncertain as to which of the beneficials to use (Heterorhabditis bacteriophora, Steinernema carpocapse, Steinernema feltiae), nematodes may be an excellent way of minimizing future infestations.

You might want to collect some of the petiole stubs left in the tree and allow the larvae to grow out in a collection jar. You'd have a better chance of identifying the pest that way.

Good luck.

miloe

Thanks sooo much for the info! Organic suits me best and ... interesting that you should refer to nematodes since I apply them to my backyard to control grubs which, of course, are larvae. A logical connection, it seems, in the treatment of the larvae infesting my tree. Will definitely give it a try and report back. I will do a spring and fall application to try to break this cycle. Thx again!

Ekka

See, dont get that here either.

Man, I should move over there where trees need humans to fix them, over here, darned things dont get a whole lot wrong with them.

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Margaret

My Linden tree is also losing leaves. Some leaves are green, others yellow and some falling on the ground. I do not think there is a bug present and wondering whether this is just because it's new to me in my new yard. It's a tall tree, but not very bushy just yet, so thinking it may be establishing its root system.


Does this tree need a lot of water? Fertilizer?
I'm in Zone 3 in Edmonton Alberta. Canada.

margaret

treevet

I posted a reply in the Welcome section I think but again Linden is not a tree that has any lofty needs for moisture EXCEPT while establishing in the first few years while developing a capable root system. No drought tolerant tree is drought tolerant the first couple of years after planting either. My new linden was all brown tipped by this time last year and today it is full and lush in it's third year. I'd post a picture if it wasn't dark out. Welcome also again.