I was only thinking of natural insecticides produced by the plants themselves.

It’s pretty hard, for example, for an aphid to become resistant to a lady bug.

GREAT solutions !!!!!

Second, most pesticides don’t actually harm the plants – they usually (nowadays in developed countries at least) are very target-specific. This isn’t to say they aren’t bad for the environment – they are – but not usually for the plants.

Finally, while intercropping and other uses of >1 plant to reduce pest pressure have some effect on pest densities (usually because its harder for a pest to see a row of its host than a vast field), there is actually relatively little support that this increases the effectivity of beneficial insects.

Thus, I think your analysis is a bit simplistic, if a good intro for laymen. But importantly, you also don’t give any good solutions. Where is the discussion about biological control? About breeding resistant crops? About, dare I say it, the potential of transgenic crops to reduce pesticide use (sure it has its problems, but it can certainly reduce pesticide application)?

All this aside, good post. I’m glad to see this kind of thinking in blogs, with at least some science behind it.

Check out http://www.weedinfo.com.au/bk_weedsosea.html Check out the list of 2,000 species of so-called “weeds” where you will find scores of edible and otherwise useful plant species tarnished with the label of weed, ironically Brassica x napus (canola) but also ginger (Zingiber officinalis), coriander (Coriandrum sativum) and garlic (Allium sativum), 3 of my favourite foods. I was amazed to open the sample page (p.241) and see pumpkin, another one of my favourites. Why is pumpkin classified as a weed? Because it is “occasionally found naturalised in rubbish dumps or along roadsides”. I think the most amusing “weed” I found on the list though is Acacia pycnantha, the floral emblem of Australia.