Should we be using aspirin as a pesticide?

Organic gardeners, like myself, must try to remember that everything is made out of chemicals including ourselves and the vegetables we eat.  Some chemicals are more dangerous than others.  This includes “natural” chemicals like belladonna (atropine) and digitalis.  A great number of medicines started their lives as plant extracts like these.   Salicylic acid has been found in most plants and was first extracted from the bark of a willow.  Aspirin (acetylsalicylic acid) is made from salicylic acid. 

Some scientists asked the question why do plants produce this chemical and it turns out to be part of the plants immune system; the way that it combats disease and pests.  There is a lot more information here:

  http://www.news.cornell.edu/releases/Dec03/take_two_aspirin.hrs.html

This is not the only immune system that has been discovered in plants; however it is the one that amateur gardeners could use to help them in their garden or allotment. 

http://www.sciencedaily.com/releases/2007/10/071004143125.htm

What about trying aspirin? I have tried it on virtually all my allotment vegetables, however it seems to be more effective when sprayed on seedlings.  

Now that Derris and Pyrethrum have been proscribed in the UK, there is little for the amateur gardener to use against pests and diseases.  Picking off pests might be alright for gardens and allotments but whether this is viable for farms I would question.  Maybe aspirin might be a way of preventing pest damage to crops that is a little gentler to the Earth than artificial, petrochemical pesticides. 

There is much that is unknown about the use of aspirin and there may be unforeseen damage to insects other than those attacking vegetables.  Yet, I have been spraying with aspirin since March 2008 and I have seen lots of ladybirds on my vegetables.
The most noticeable affect that I have seen is the reduction of whitefly on my winter brassicas. It almost encourages me to start to grow kale again.

The two unknowns about aspirin application to plants are the dosage and the timing. I have used 2 tablets in 10 litres (2 gallons) of water. I only sprayed seedlings once but the veg. about once a month.   I have used dissolvable aspirin in these experiments.  I know that other people are using willow water made by marinating fresh cut willow branches in water.  As some organic gardeners object to the use of synthetic aspirin, willow, a good source of salicylic acid, water could be used instead.  So we could argue that spraying with aspirin is similar to spraying with nettle or comfrey extract as a pesticide.
A more effective way of extracting salicylic acid from willow bark is to make it into a tea using boiling water. 

Rather than using the organic label, I would rather the: "natural" label. Maybe that is just as difficult to define, but I mean by it that I am using nematodes, fungi and bacteria to combat diseases and pests. And I use a barrier rather than chemicals that are not usually found in nature. Aspirin, as I said at the beginning, is found in most plants.  I would suggest that it may be one of the more benign of the chemicals that plants produce and therefore a chemical that we can use to advantage on the allotment.