I have an ongoing problem with black aphids in my garden. They lay waste to my spring onions, garlic chives, normal chives, garlic (when I grow it) and pretty much anything else I plant in the allium family.
Black aphids thrive in moist conditions and particularly enjoy weaker plants. Because my garden gets less than full sun I think my plants are particular susceptible.
Here are some attacking a baby garlic chive plant:
I have tried squishing them. I have tried spraying them off with the hose (a technique I find effective with normal aphids). I have tried chilli and garlic sprays. No success. The only thing I can find that gets rid of them is pyrethrum.
Hence the question – should I use it? I know it’s generally considered a ‘safe’ pesticide, but not necessarily by everyone. I also know it can kill beneficial insects if they come into contact with it.
So should I use it? Do you use an insecticide? Or another method for containing the bugs?
Have you tried insecticidal soap, that works in the short run for me. The best long term strategy I have is to keep plenty of flowering plants in the garden to lure in adult beneficial insects whose offspring will feast on aphids. Sweet alyssum, coriander, fennel, dill or any other umbelifera in bloom will attract parasitizing wasps or hover flies or other good bugs. It takes some patience but once you establish a population of good bugs it is amazing how much help they can be.
Yet another good reason to keep trying to grow coriander in summer. I’ve been struggling with the dill this year – doesn’t seem to want to take. Funny given that you guys call it ‘weed’.
Definately try the soap cure. I had massive numbers on my new plum tree sapling – so thick that the tree looked black. It was made worse by the ants shepherding them so that the natural predators couldn’t help. If it wasn’t for Yates Naturasoap I would no longer have a plum sapling.
Ants shepherd the green type aphids on my tamarillo – I’ve always found it an absolutely fascinating thing. Thanks for the advice re:Naturasoap
I definitely agree with Michell regarding beneficial bugs. I struggled with recurring aphid plagues in my small courtyard garden for over a year. The cycle was finally broken by importing lacewing larvae. They were integral to returning the balance of good/bad bugs. I also companion planted with good bug attracting plants such as Michelle mentioned. Now when there is the occasional aphid population flare up I use either Eco-oil or neem oil ASAP! Both are very effective & don’t harm good bugs.
Hope this is useful.
I haven’t tried Eco-oil but think I should. I do like the companion planting idea – I just need to do a bit of research re: what eats the black aphids – not sure if it is ladybird like the standard aphids – I have never seen any on the affected plants.
I do use pyrethrum for several pesky bugs I get, including squash bugs and flea beetles. Aphids are not usually a big problem for me, and I use neem oil or insecticidal soap for them when they do appear.
I don’t what it is about these black aphids – they are particularly virulent.
I try not to use anything on the bad bugs where possible, as it doesn’t take long for the good bugs and their babies to move in and decimate them. It sometimes takes a couple of weeks for this to happen though, so if the bad bugs are voraciously devouring something that I can’t bear to lose, and I can’t see evidence of any good bugs I’ll reach for the Yates Naturasoap.
I’ll have to have a look for Naturasoap, sounds interesting.
Neem oil is good. I have occasionally used pyrethrum in the past which worked with aphids however now I have a bee hive, it’s a big no no.
The bees would complicate things, thanks for the tip – I will try neem oil.