Chris Hogg wrote:

Would some kind person admit me to the mysteries of using soft soap as
a mild insecticide?

What constitutes soft soap in this context? I presume washing-up
liquid isn't appropriate. Do I have to cut a chunk of a piece of
'Knight's Castile' or 'Imperial Leather'? Is soap for washing clothes
the right stuff such as Persil or Lux?

How much soap should I add to how much water (grams/litre,
ounces/gallon or whatever)?

How does it work? I've seen one suggestion that it clogs the breathing
tubes of the insects as it dries. Another explanation is that it
simply lowers the surface tension of the water and this then fills the
breathing tubes, so they effectively drown.

All advice gratefully received.


Its traditional 'soap' ie fat and potash mixture which is I remember
correctly is mildly caustic.. It stings the little swines something
terrible.. This is the primary effect of soft soap IIRC. There may also
be a blocking element to aphids breathing tubes, when you're that small
a large squirt of soap makes it hard to breathe!-)
You can effectivly make it out of ashes (to produce 'lye') and fat and
a few other things.. You will find recipes for it in old gardening
books and a description in the 'Ingalls Wilder' series 'Farmer Boy' of
it being made in the around the turn of the century (or before).

The stuff that clogs dries that you are thinking of is made from
Rapeseed oil though I suspect it may contain a soapy element as an
adjuvant.

The 'normal' washing up soap is a detergent and is not quite the same
thing.

http://www.chempak.co.uk/ are my normal suppliers for this product.
They do mail order and stock to some shops.
I find 1 tub lasts several years ususally and its much cheaper than
'Safers' or 'Bio' or any of the other ready diluted, overpackaged
products.
//
Jim