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From: miw@uqcspe.OZ (Mark Williams)
Newsgroups: sci.bio
Subject: Re: pesticides
Message-ID: <1543@uqcspe.OZ>
Date: Fri, 21-Aug-87 03:32:24 EDT
Article-I.D.: uqcspe.1543
Posted: Fri Aug 21 03:32:24 1987
Date-Received: Sat, 22-Aug-87 20:01:15 EDT
References: <4960@ihlpa.ATT.COM> <1039@faline.bellcore.com> <8997@tekecs.TEK.COM>
Reply-To: ccwilliams@wombat.decnet.uq.oz (Mark Williams)
Organization: Prentice Computer Centre, University of Queensland
Lines: 29

In article <8997@tekecs.TEK.COM> andrew@lemming.gwd.tek.com (Andrew Klossner) writes:

>	"So now he's back on the family farm without chemicals, still
>	producing as much per acre as his neighbors, but making more money..."
>
>An analogous situation from epidemiology suggests itself.  With regard
>to vaccinations, most of which have a small but non-zero chance of
>doing you harm, the ideal for you is for everyone else in the world
>except you to be vaccinated.
>
>Weeds come from weed seeds; insects come from other insects.  Perhaps
>this farmer's chemically soaked neighbors formed a weed-free,
>insect-free buffer around his farm which kept the invaders at bay.

	Good point, but this actually doesn't work in practice. Weeds and
bugs reproduce very quickly, and are never wholly eradicated. Pesticides and
weed-killers are also often ineffective against eggs and seeds. One weed can
easily produce enough seeds to infect tens of hectares of land. It is not
want of reproductive capacity, but want of 'lebensraum' that stops bugs and
weeds from taking over the earth.
 
                              Mark Williams
ccwilliams%wombat.decnet.uq.oz@seismo.css.gov

-- 
The views expressed above are not necessarily those of my employer. In a
couple of hours they may not even be my own.

"Convictions are more dangerous foes of truth than lies"  ----Nietzsche