Willow & plum trees and aphids

cruizinat91k

Hi all, I'm a long time lurker but 1st time posting.
Living in Co. Cork, we're trying to do some rewilding in the garden and help the bees & insects.


However... one of our plum trees and a willow (not sure what type but not a weeping willow) have been completely infested with what looks like a small black aphids.

The infestations are only on the new tender growth but it's very dense infestation - every square mm of shoot & leaves are occupied by these aphid lookalikes. Pics attached.



Plus on the willow the leaves have some weird pale green bumps which I've never seen before. Is that related?


Anyhow, we removed the new growth tips from the plum tree a couple of weeks ago and that seems to have been successful. Reluctant to do the same for the willow 'cos it'll mean pruning more-or-less right back to the trunk 'cos these guys are on the tip of *every* new shoot.


We have apple trees which do get greenfly (99% eliminated with neem oil), but these guys are smaller and blacker.


Anyone seen this before and have targeted suggestions?


Thanks for any help.

macraignil

The photo of the shoot tip does look like a bad infestation of aphids and I have read about cutting off the infested tips on plants like beans but have not tried this on other plants myself. The green bulges in the other photo are not clear enough to make a positive identification for me but I would suspect a type of scale insect. There are also types of gall wasp that are not damaging to trees but will make unusual growths on them that they can live in. The scale insect can usually be brushed off if they have become a problem. I am more inclined to leave nature take its course with trees and shrubs. It is possible to hose off aphids or squash them or as mentioned scrub off scale insects but these are also food for life forms that would provide a natural biological control in the garden and with strong plants I will often leave some pests to attract the types of life that will use them as food. There are some people that recommend a dilute solution of washing up liquid for aphids but I prefer to use them as a way to feed solitary wasps, hover flies, lacewings and ladybirds.
Happy gardening.

tromtipp

I have a lot of black aphids on some (not all) stems of wild knapweeds growing both in meadow grass and in a flower border. They're making me a bit twitchy as I have a vegetable plot not far away, but I'm hoping (a) that they are acting as a decoy keeping the aphids away from more delicate plants and (b) that as soon as it gets warm the hoverflies, ladybirds and all the rest will start to predate them and get the numbers down.

cruizinat91k

okay, I'll leave them for the moment then and see how things develop.
If they start spreading though¸ I think I'll not wait long before cutting the willow right back.

@macraignil, the bulge in the leaf is actually *in* the leaf - not on top nor on the bottom. So not something that can be brushed off. I dissected one of the lumps but didn't find anything of note inside.

Thanks both.

Jim_Hodge

Most times it's best not to panic and rush in with removing aphids. Often, nature will take care of the issue. Gardens World, many years back, showed rose bushes covered in aphids one week which were clear the following week thanks to birds and other predators. I have little bother with them as the garden is very much nature focused and keeps the balance nicely.

macraignil

cruizinat91k wrote: »

okay, I'll leave them for the moment then and see how things develop.
If they start spreading though¸ I think I'll not wait long before cutting the willow right back.

@macraignil, the bulge in the leaf is actually *in* the leaf - not on top nor on the bottom. So not something that can be brushed off. I dissected one of the lumps but didn't find anything of note inside.

Thanks both.

If they are not scale insect that are possible to brush off then my other suggestion was some sort of gall forming wasp and this information page claims a type of saw fly can cause leaf galls in willow and removing the leaves effected can be done if you feel it helps but is not necessary.