Return of the sand grain-like leaf mystery. Fungus? Bugs? Help!

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Hello again o wise ones. I posted about this back in the fall when it was affecting some, but not all, of the leaves on my trident maple. Now that the leaves have emerged from the buds, to my horror, this strangeness is now covering every leaf. Is it a fungal disease? Could it be bugs? These bizarre salt crystal-like dots are spread across the whole foliar mass of the tree, usually following the morphology of the leafs canyons.

Last year these leaves became malformed when the dots were present. The dots never grew. How can I treat this? Should I isolate the tree from my others?

I hope someone here can tell me what I am looking at in the pictures that I attached :)

Thank you in advance
 

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Leo in N E Illinois

The Professor
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Quite honestly, I can't tell what you have. But, in my experience, I would try treating for mites. Spider mites, false mites, flat mites, two spot mites, I would guess it is one of the mites. Invest in a miticide, an insecticide will not work, mites are not insects. Treat at label recommend interval, keep repeating treatment at least one or two cycles after foliage starts to grow out clean. This is important, if you stop treatment before every last mite is dead the survivors will be resistant to the pesticide you chose.

Spend time reading labels, either at your local big box stores or on line. I purchase from http://www.hummert.com
 

Wires_Guy_wires

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Wow, this is a first for me in maples. But I know that some plants, when in extreme health, will push our sugars and other carbohydrates. Orchids are known to do this a lot, but any plant could.
You could rule that out by a simple taste test; put a few of those droplets on your finger, check the texture (if it's honey like sticky or not) and taste it. This can also happen as a result of insect damage, mainly beetles, cicadas (every kind, even the ones that live in colder regions) or thrips. Thrips tend to leave a silvery shining spot in the foliage they've damaged, but it might be different with very young foliage.

Otherwise it could be cuticle resin/wax, which would give an oily shine to everything it touches. You can test this by putting some of those droplets on a toothpick and put it into hot water. If it's wax, it will dissolve and form a layer on the side of your glass. It will not be sticky at all.

Some fungi will produce spores on spikes, but I don't believe that's what we're seeing here.

Mites are a long shot, they tend to prefer the underside of foliage, so one would expect the 'signs' being more present on the underside of every leaf.
 
Messages
71
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22
Location
Pittsburgh, PA
USDA Zone
6b
Wow, this is a first for me in maples. But I know that some plants, when in extreme health, will push our sugars and other carbohydrates. Orchids are known to do this a lot, but any plant could.
You could rule that out by a simple taste test; put a few of those droplets on your finger, check the texture (if it's honey like sticky or not) and taste it. This can also happen as a result of insect damage, mainly beetles, cicadas (every kind, even the ones that live in colder regions) or thrips. Thrips tend to leave a silvery shining spot in the foliage they've damaged, but it might be different with very young foliage.

Otherwise it could be cuticle resin/wax, which would give an oily shine to everything it touches. You can test this by putting some of those droplets on a toothpick and put it into hot water. If it's wax, it will dissolve and form a layer on the side of your glass. It will not be sticky at all.

Some fungi will produce spores on spikes, but I don't believe that's what we're seeing here.

Mites are a long shot, they tend to prefer the underside of foliage, so one would expect the 'signs' being more present on the underside of every leaf.
This is very useful. I will try some of this. What do you mean by "in extreme health"?
 

Wires_Guy_wires

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With extreme health, I mean that the plant has been producing more carbohydrates than it can store and consume, the excess will burst some vesicles and leak out of the plant on the weakest spots, usually the foliage or soft twigs, sometimes even the fruits.
It's not always sweet, sometimes a bit starchy in taste. Stickyness will help you zone in on if it's either wax or something sugary.
 
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