Three simple steps to prevent black aphids

As we move into December, aphids are having a festive celebration of their own – at the expense of our plants! If you live in an area of high humidity, this is even more true.

The black spots or bugs you see on your onions, chives and garlic are black aphids. They are merrily multiplying and sucking the life out of your plants!

Look closely and you will observe that some appear bigger than others – these are the ‘mothers’, which have wings. Interestingly, these ‘mother’ aphids do not produce eggs, but simply drop hungry young aphids straight on to your plants to feed.

You will often find them in a long line, as every couple of days more young are laid, and they can produce up to five every couple of days. The fascinating thing is that all their babies are girls!

Where did my infestation come from?

The adults overwinter in the warmest spot they can find in your garden to protect themselves from the cold and frost so, if like me, you have no frosts or snow, your aphid population is likely to be much, much higher than somewhere that enjoys a strong winter chill.

Black aphids really like to overwinter in the thin skins of garlic or shallots and, for the life of me, I have never been able to see them! Yet as soon as the leaves start to sprout, the mother gets ready to lay on the small vulnerable leaves. From here, they pierce the young leaves, full of sweet carbohydrates, and start to suck.

Slow at first, while the temperatures are cool, but as soon as the sun comes out, it is ‘yeehaaa!’ This is it can seem you have an infestation overnight!

How do I control black aphids without harsh chemicals?

When my first leaves appear on my garlic and onions, I spray with Naturally Neem and then use EnSpray 99 oil in the following weeks. I have found that Naturally Neem is the best Neem product you can buy, as many Neem products are not refined enough for edible application. Remember Neem must be sprayed in the cool of the day only.

If you have a large infestation, my advice would be to pull the plants out carefully and submerge them in water to prevent any of them re-infesting elsewhere.

You can still eat the produce, it just may not be as juicy…

As ever in organic gardening, prevention is key. Here’s my advice on how to prevent black aphids in three simple steps:

1. Keeping your plants healthy from day one can really help deter an infestation and I use regular spraying of Liquid Kelp, which keeps the plants strong. Kelp strengthens the cell wall of the plants, making them less attractive to the aphids, who are after the easy prey of weaker plants.

2. If you are buying chives, onions or leek plants at a garden nursery, I also recommend checking the leaves carefully, even in between each leaf, as they can be hiding in there.

3. Beneficial insects can be your friends too – encourage ladybirds into your garden as they will eat aphids and take care of the problem for you! Check out my earlier blog here to find out how.

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Happy gardening and wishing you all a very merry Christmas!

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