spirelli
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One-off (organic?) aphids control

We need to ask a gardener to apply an insecticide to a cherry tree. Neighbours have complained about the tree being infested by insects.

For reasons I cannot go into, there is no regular access to the tree. So we want to ask someone to come once and apply some kind of insecticide.

We want it to be organic – so no adverse effects on other wildlife and humans. What would be a sensible option in this scenario, I.e. what should we ask the gardener to do/apply?

Many thanks.

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applestar
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Hmmm... My reaction if aphids is the issue -- aphid population will attract beneficial predatory insects as well as birds. If you spray or apply some kind of systemic, then the predators will be killed or injured/weakened and more aggressive aphid and other pest issues will follow.

Furthermore, if you spray while the cherry (and other trees and flowers) are blooming, this will most probably kill honeybees and other native bees.

What exactly are your neighbors complaining about? What is their concern?

I have trouble with black oily aphids on my cherry trees. I'm wondering if that is the target pest in this instance.

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rainbowgardener
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By one-off, you mean do it once and never again? Sorry, no such thing. You can by various chemical or organic means get rid of all the aphids on your tree. You can't get rid of all the aphids in the world, so eventually they will come back.

Not sure what the neighbors are complaining about. If it is your tree, why do they care if it has lots of aphids? Not like your tree is the only source of aphids to come in to their yard.

I agree with applestar. There are always going to be aphids. When there is a major infestation of aphids, enough to significantly damage a tree, it is because things are out of balance. When the system is in balance, there are aphids and there are ladybugs and lacewings and praying mantis and grasshoppers and hoverfly larvae and chickadees and titmice and warblers and frogs and toads. All those other things eat aphids. If there are enough of the other things, there will always be some aphids, but there will never be major infestation.

While you are working to create a system that is in balance, with habitat to attract some of all those other things, some of them like ladybugs and praying mantis can be imported in to your yard, you can buy them on line.

imafan26
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Agree, especially if you want to be "organic", none of the organic chemicals have a long lasting effect and systemics will work, but they are not organic. Eventually, even they will wear off and the bugs will be back and in the meantime you will also be harming the beneficial insects.

If they are aphids or scales and you have sooty mold on the trees. Take care of the ants by putting out ant bait. Ants will protect the aphids and no beneficials want to get into a fight with them even if there are a lot of aphids to eat. Killing the ants you see does not solve the problem so you really have to go after the queen and the boric acid baits are weak enough not to kill the ants outright and the worker ants will live long enough to feed it the queen(s) and kill her.

You can hose off the tree with a strong jet of water. If the tree is too big to do that, take care of the ants and use the organic methods to take care of the aphids which may have to be applied every week until you get control

Prune the tree but do it right or the shape will be ruined forever. It is expensive to have it professionally trimmed but if the tree is big, it is probably safer and make it part of the contract, that they haul off the trash. And make sure they are licensed and have insurance. If you hire a professional arborist, he may also ask him if the trees location may become an issue and he will also know what to look for if the tree is sick. Bag and burn (trash) the remains. Unhealthy plant residue should really not be composted especially if your pile does not get hot enough. A smaller canopy might be easier to treat.

Healthy plants make poor targets. Feed and water the tree. This is the one time when I truly believer in compost tea and adding organic matter to the soil to promote a healthy soil environment. Cherry roots are shallow so you could apply the compost as a mulch.

If the tree is near a property line, the neighbors concern may be really more about invasive roots and rubbish that falls into their yard. Trees that have shallow roots and grow fast are more likely to cause problems than slow growing deep rooted trees, but if they are not planted far enough away from houses and water/sewer lines they can still cause problems.



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