splinter_paul
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WHAT HAS CAUSED MY LABURNUM TO SUDDENLY PRODUCE TREE SAP

I have a laburnum on my front drive and this year it has produced loads of tree sap - covering my car and block paving. In all the 10 years I have lived here I have never had this - why has it suddenly started doing this? I did have block paving done some time last year - would this be a cause?

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Kisal
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Welcome! I'm not familiar with laburnums, but could it be that your plant has aphids? They excrete a sticky substance known as "honeydew" (much loved by ants, BTW), which can drop onto surfaces below. Just a guess. :)

ETA: you can wash a good majority of the aphids off of the plant, using a garden hose.

splinter_paul
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Yes it has got aphids and I have scrubbed as many of them off as I can using soapy water but cannot reach the top of the tree because it is too tall - will the rest of the aphids die off on their own? Will it harm the tree?

mbaker410
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How big/old is the tree? I would like to think that if the tree is old enough then no I can't see the aphids doing any real damage to the tree (like killing the tree). It may kill some leaves or even a branch but the natural order of the food chain will most likely kick in and kill the aphids for you.

Natural predators include ants, lady bugs, spiders etc.

So if you get what you can off nature may take care of the rest. You may even want to try and locate, catch and introduce some ants to the tree and the aphids. Ants make quick work of them as the simply love the "honeydew".

I have three healthy cukes in my garden and my location has a ton of ants unfortunately but it has worked out for the garden and my house because the ants are concentrated by the cukes, keeping any aphids off, and it also keeps them out of my house.

Mike

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Kisal
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mbaker410 wrote:Ants make quick work of them as the simply love the "honeydew".
Y'know, I have never observed ants harming aphids. That doesn't mean it doesn't happen, though!

I used to have a big old tulip tree in my back yard. A person couldn't sit under it without getting rained on by ants and aphids! But the ants were actually "farming" the aphids, carrying them up and down the trunk of the tree, and gathering around them on the leaves to stroke them, "milking" them of their honeydew. :)

mbaker410
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I wonder if different ants have different ecological relations with aphids? I just know that when I was growing from seed and would put my plants outdoors I got tons of aphids on my plants.

Now I have 0 aphids and tons of ants. So I will look a little closer and observe . Will let you know what I find.

Mike

mbaker410
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Here is somethings I found after a quick search of a couple sites...

"Often, ants are often the real culprits because some species of ants tend aphids the way farmers do cows. The aphids suck plant juices out of stems and leaves, and produce a sticky substance called honeydew. The ants eat the honeydew. I’ve read that the ants will protect the aphids from other ants or insects by stinging or biting them. And when the aphids have sucked the plant juices dry, the ants will move the aphids to another location."

So maybe its just a coincidence that the aphids are gone from my cukes and that the ants are there? I may have a lot of lady bugs around that I don't see but either way I look into this now that I can't seem to find anything that says that ants actually eat aphids.

I did some more research into the predators of aphids and here is what wikipedia had to say...

Predators: lady beetles (Coleoptera: Coccinellidae), hoverfly larvae (Diptera: Syrphidae), parasitic wasps, aphid midge larvae, aphid lions, crab spiders[22] and lacewings.

Mike

splinter_paul
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The tree is over 20 years old and this is the first time its happened. Hopefully (like previous posts have suggested) nature will take its course and this won't occur next year. If it does, then I'll be more prepared.

Thanks for all your advice - this is a great site and no doubt I will be back again in the future.

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