Saint Ambrose

Saint Ambrose
Photo: Journey Worker Productions, CC SA 3.0 (C)

Wednesday, 14 January 2015

Aphid Attacks

This is part one of several posts about aphid infestation eating kale plants.

I had several pots containing several kale plants in early 2014. Mostly Melbourne green kale, but some Toscana too. The toscana variety I have found to sprout well and grow tallish initially (to 4-6inches), but is irresistable to bugs, so I have more or less left it as a sacrificial plant for the grubs, while everything else in the same pot flourishes (especially the Mustards).

Recently (summer 2013-2014) we have had an infestation here of two particular pests -  cabbage moths and horrible horrible grey aphids.

Grey aphids - pictured - are so horrible. They sit on the new growth of the plant, sucking out the sap and slowly draining the energy and life from the plant, barely moving at all as they do so, in clusters that grow and grow. They love brassicas. When you crush them between your fingers, they have a horrible light-acrid insectish smell.

I am surprised we dont use them as a metaphor for the growth of bureaucracy.


Up till now my idea of pest control was to plant something else, overload planting (putting about a dozen things in one pot, instead of the orthodox advice about one plant per squatre foot or whatever), and killing snails, slugs and cabbage moths manually.

(I will write something on fast ways to kill cabbage moths at some point)

So I wanted to kill the grey aphids and set up a little experiment. Of the kale buckets, there are the following:

Bucket 1: two large 2ft kales, both post-seed (kales are biennials you might know, these planted in april 2013. So still flourishing). Badly infested with G-A.
Bucket 2: 1 large 1.5 ft kale and three smaller 6inch ones still growing but clipped back for salads regularly. No serious G-A.
Bucket 3: one 1ft kale, very healthy, and a few smaller ones in development. Quite bad G-A.
Bucket 4: three very large (3ft) kales, really flourishing. Of these, two have bad bad G-A infestations, one is moderately infested.
All have bad cabbage moth infections.

So I made the following organic control recipe to spray on them:
2 onions, 2 lengths of leek, several garlic pieces, some cut up solanum nigrum leaves. And some flaxseed oil to make it oily and syruppy. I boiled this into a sort of soupy-sludge, strained it, and then added some portugese piri-piri sauce (this stuff is a portugese version of tobasco sauce basically).

It smells horrible, like italian cooking extruding through a dead person's skin. Horrible.

I sprayed this once it cooled on Bucket 1, Bucket 3 and two of the three kales of bucket 4 on saturday.

It hasnt rained since and the stuff has stuck on.

It sort of worked. The grey aphids seem to have gone quiescent and not died (Id like to think - I have no idea actually what the effect has been); the cabbage moth-caterpillars are still going strong so Ive been picking them off the leaves. BUT - I have noticed that the multitude of white cabbage moths (as many as 6 at a time hovering around previously) now avoid these kales altogether, indeed, they are trying out landing on nearby parsnips rather than landing on the kales. Thats pretty desperate!

That means this syrup is a quasi success as a repulsive-repellant agent, but not as a poison.

I just took the spray and manually sprayed off all the aphids from bucket 3. This means it no longer has so much spray on the leaves either. We will see whether it becomes attractive to the cabbage moths again...

My plan next: depending on how spraying down the aphids on bucket 3 goes, I think I will do the following:

use the jet spray to hose off the aphids as best as possible (probably in another area than the garden).
Wait till they dry.
(next day)  Prepare a fresh solution of bug-killer-spray, this time without the solanum leaves, but adding an organic detergent to dissolve the waxy coating on the aphids and the caterpillars.
Respray & leave.

Then see how long it takes till the pests come back...

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