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Major yarrow aphid infestation

bac2aribac2ari Posts: 9
in Problem solving
Hi there,

I planted groups of ‘Lilac Beauty’ achillea in my perennial bed last year a bit late in the season for them to flower so was looking forward to seeing the blooms this year. 

However, since spring I’ve been fighting a battle with yarrow aphids (distinctive with their jet black legs), and I’ve definitely lost! They have colonised in huge numbers and I can’t get on top of it. Pesticides are not an option and squashing them isn’t practical there are too many! Amazingly the flowers have come through but I’ve had to resort to snipping off many buds daily to get the numbers down. There are not many predators around that I can see, we had plenty of soldier beetles earlier in summer, no sign of ladybirds and I’d need an army of them! Ants are starting to appear, I read they come after the aphid sap. 

Anyway, looking for advice as to whether I keep them or get rid of them at the end of the season? Will the same problem be repeated next year if they over winter. They haven’t spread to any other plants presumably they love achillea only! But they might spread diseases? Shame as I really needed that umbellifier shape to finish the bed :/

Many thanks 


Posts

  • nick615nick615 Posts: 1,487
    Some people have an aversion to this but, as you're not dealing with a food crop, it may suit you.  Boil some rhubarb leaves, drain of the liquid when cool and, using a household spray bottle, spray the aphids with it.
  • bédébédé Posts: 3,095
    bac2ari said:
    squashing them isn’t practical there are too many

    Squashing may be your only option.  Keep at it.  Daily, twice daily +++
     location: Surrey Hills, England, ex-woodland acidic sand.
    "Have nothing in your garden that you don't know to be useful, or believe to be beautiful."
  • FairygirlFairygirl Posts: 55,117
    A strong jet from a hose, or a squirty bottle, or wipe with your hands.
    Not something I've ever encountered - and I do grow yarrows, and always have. Any bog standard aphids are eaten by the birds in my garden so they're rarely, if ever,  a problem.
    Whereabouts are you @bac2ari? Perhaps it's a common problem where you live, or you don't have the necessary predators to pick them off for you.  :)
    It's a place where beautiful isn't enough of a word....



    I live in west central Scotland - not where that photo is...
  • bac2aribac2ari Posts: 9
    Thanks for the advice everyone. Rhubarb sounds interesting will give it a go. I have tried neem oil blasting but they still came back when I was on holiday. I’m in Edinburgh. I’d never seen these kind of aphids before either - had to Google them. Maybe I can leave the achillea in til next year but be majorly vigilant in the early spring and see how it goes. Hard when you’re out at work most of the week! 
  • FairygirlFairygirl Posts: 55,117
    Interesting @bac2ari. Not something I'm aware of, but our climate here is considerably different from the east side, so perhaps that's the reason. Much drier in the east.
    Do you have problems with aphids generally?
    Wiping them off early in the season is the best solution if you don't have small birds in your garden, although they are the best solution of all, so it's worth having some hanging feeders near any susceptible plants.  Blue tits, in particular, are very keen on them, and when they have their youngsters to feed, they hoover up loads of them   :)
    It's a place where beautiful isn't enough of a word....



    I live in west central Scotland - not where that photo is...
  • LynLyn Posts: 23,190
    Try a spot of fairy liquid in a spray bottle. 
    Gardening on the wild, windy west side of Dartmoor. 

  • bac2aribac2ari Posts: 9
    Thanks @Fairygirl I’ve never had a significant problem with regular aphids before. There bird feeders is a great idea - there are virtually no small birds in that section of the garden (two wood pigeons probably keeping them away). 
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