Onion aphids :(


I love alliums, and grow lots of different kinds to eat throughout the year. Over the years I’ve had leek moth and onion fly, but never before onion aphids. At first I thought they must be something else as they are shiny; this, as well as their colour (black), is probably why neither I nor my husband, who is much better with a camera than I am, have been able to take photos of them. Still, having googled extensively, I see that this is what they are.

Has anyone else in the UK had these? I see they are unusual here. My bed of everlasting onions (Allium cepa perutile) is smothered in them, and since none of my other alliums seem to have been affected as yet, I’m tempted to dig up and destroy the whole bed.

What do you think?


Poor you Rachel - and poor alliums.

I’ve been lucky enough to never have onion aphids. But this year I have had a bad attack of rust on one of my chive plants. I cut it right back (removing all the leaves), and moved it to the other side of the house, as far away from the other chives as I could. So far so good… The new leaves are growing without rust and it doesn’t seem to have spread to the other chives… yet. Fingers crossed.

Do you have the option to dig up the infected plants and move them somewhere away from the other alliums?

PS Any thoughts on why they became susceptible? I read that alliums are more susceptible to rust if there is too much nitrogen - and I think this was probably why mine became infected. I wonder if it is the same with aphids…


Hi Mark

I have some onions (of the same kind) that aren’t affected…in the fridge! They grow in clumps, so I dig up one clump at a time and replant one or two onions from the clump. I then use what I want to as spring onions, and put the rest in the fridge to keep until I next need them. So, yes, I will plant them elsewhere - maybe on the allotment. I think I may dig up and destroy the rest. :frowning: . These particular onions are much less bothered by pests than my other alliums, so I think the aphids might like the other ones even better! :frowning: Apparently these aphids are relatively new in this country.

As for your rust, I often seem to get it on my garlic at the end of their growing period - which isn’t too much of a problem - but have also had it on leeks at a time that has really affected their growing. I haven’t had it on chives at all - yet. The advice I’ve found that helps for this - as a preventative - is to add potash in the autumn, which I did by using comfrey fertiliser on them. I think the spores are always around, though, so probably not worth destroying everything to eradicate.