What is on my brassica's?

[Heidi]

We went to the allotment yesterday to build a large clouch over the brassica bed. Up until now we've had 3 mini clouch tunnels over the 3 rows (2 rows of purple sprouting broccoli and one row of brussels).

When we took these off, on a few of the broccoli there was some sort of bug in the centre leaves, and also a sort of grey ash-like substance.

Any ideas?

The bugs looked a bit like aphids - are these wooly aphids? And what is the grey substance?

Haven't got any photos as we forgot to take the camera!

[Flummery]

Without seeing it it could be whitefly. They have this greyish fluffy appearance on curly kale when I grow it. You can spray with a drop of washing up liquid on water in a hand held sprayer and wash them off. If you get a bad infestation and don't tackle it you can get distortion on the leaves, but the crop is still edible if you wash the things off - just doesn't look so pretty at this stage.
Give 'em a wash!

[Cutecumber]

I think it's mealy cabbage aphid.

The aphids are covered in a waterproof coating which is grey and sort of waxy.

They are very problematic when they get into the heart of brassicas - they're in my savoy cabbages at the moment. They are a total pig to get on curly Kale too, because the leaves hide them so well.

I pick off and squash what I can, get water sprayed into where they are hiding, and keep going back and checking. You can use some soft soap, too. Be careful using any physical or chemical pest control on the growing tips inside brassicas - they are very sensitive. Leaves are tougher.

There's a photo of them on this page


http://www.pestspotter.co.uk/pests/pests.htm

[Flummery]

Urgh - that page makes me feel itchy! Thanks for the link though, Cutecumber. That's what I've had on kale too. The whitefly shift in clouds if you tap the leaves but these things stay put unless washed away. Soap or detergent breaks down the wax to make it easier to move them.

[Heidi]

Many thanks!

Yes i think you're right - they're Mealy Cabbage Aphids.

Hmm well i gave them a good soaking yesterday of water, but will have to try a soap solution too then. At least they're just on the leaves at present, as there are no flowers/buds yet on either the broccoli or brussels.

Thanks for the advice - i did wonder if they were some sort of aphid, so i found a lady bird on another part of the plot and dropped it on the broccoli, so hopefully she's making short work of them too.