Coccinella

The ladybirds arrived in tact. It was raining so in an effort to avoid them all dieing in the rain they were kept inside and fed on aphids overnight. Next day 10 were released, 5 on the brussel sprouts, 5 on the cauliflowers. The remainder were kept two more days until the weather cleared up a bit and released. It's now a few days later and no sign of any ladybirds anywhere!

I have noticed that the aphids are not spreading very quickly. It is as if one plant is weak and the aphids prefer that one - leaving the others relatively unaffected. Alternatively, the wasps are doing their job. Its a sunny day today and there's a few hoverflys around too. They, apparently, eat the aphids too. It's reasonable to assume the spiders in the cauliflowers are doing likewise.

Undecimpunctata

Zonda can supply 25 of the 11-spotted ladybird (Coccinella undecimpunctata) to chomp on my brassica aphids for $12.50 (+GST +shipping = $25.31 total). Time for another habitat experiment in the vege patch. This time, with the right species, there's some chance the aphids will be someone else's supper and the brassica mine.

Ladybirds not Wasps

Zonda kindly replied to my email with the information that only one wasp has been recorded attacking Brevicoryne brassicae. I'll bet it isn't Aphidius colemani because there appears to be no appreciable difference in aphid numbers.

Zonda told me that the 11-spotted ladybird likes to eat my aphids. Anyone got a supplier?

Wasps

There are only two suppliers of wasp in the country, BioForce and Zonda. Neither can supply Diaeretiella rapae. Zonda tell me Diaeretiella rapae is, itself, parasitized.

No commercial suppliers of the wasp leaves two possibilities, either domestic supplies or source a different preditor.


Wasp mummies in an oragami basket put out in the hope they will attack the aphids.

Aphids

Aphids
The seemingly never-ending hunt for the cure for aphids has lead to a new experiment, but first aphids.

According to the Wikipedia article on aphids there are over 4,000 different species. There are even native New Zealand aphids. There's tons of good words associated with aphids - look these up: parthenogenetic, ovoviviparous. Pretty nasty hu?

Of course any nasty insectaside will kill these beasts, but I don't want to do that. One of the reasons for growing vegies in the garden is to avoid toxins. The alternative "naturals" include Yates "Natures Way Insect Spray" which you have to keep applying every week. I don't want to do this either, for the same reason.

According to this article - planting flowering plants to attract the hover flies doesn't work.

Removing and insinerating plants is hardly control - so I'm not doing that. The other often cited control method is to rub then off by hand (no thanks).

Aphid Control
Take a look at the photo, I think these are grey cabbage aphids. Actually, they aren't grey they are green but covered with a grey waxy substance. Species Brevicoryne brassicae. Populations peak in October-December and March-April.

They are seen in the vegetable patch on brassicas including: cauliflower, brussel sprouts, and sweed. They no-doubt also attack: turnips, cabbage, broccoli and others in the family.

There's a natural parasitic wasp Diaeretiella rapae that lays it eggs in this beast and will keep aphid populations under control.

Aphidius colemani vs. Brevicoryne brassicae
The experiment is this: I can't find a supplier of Diaeretiella rapae, but BioForce Ltd. supplies Aphidius colemani, a tiny 2-3mm parasitic wasp that attacks several species of aphid (hopefully including mine). 100 wasps for 10 bucks. With some luck they'll attack my aphids and the problem will be a thing of the past. BioForce doesn't have a web presence. I ordered 100 wasps, they come as mummues (aphids with the lavae in it) and I've released then in half a dozen places in the garden a couple of days ago.