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GM crops benefit non-GM crops nearby

Do you remember how, back in the days when genetically modified
crops were as vilifed as climate sceptics were until recently, one
of the arguments deployed against them was that they would
`contaminate’ neighbouring farms with their genetically modified
pollen? This was one justification for a total ban, as there still
is in Britain, rather than a policy of live and let live.

Now comes evidence of a different kind of collateral
contamination by GM crops. Turns out GM maize contaminates
neighbouring farms with extra profits. The fact that farmers are
growing insect-resistant GM crops raises yields for those who are
growing conventional maize, because it reduces the number of pests
that are about.


By comparing
actual insect damage against estimates of what damage would have
occurred – derived from historical data and other measures of borer
abundance – the researchers calculated that over the 14 years of
their study, use of Bt varieties improved farmers’ profits by about
$3.2bn in Illinois, Minnesota and Wisconsin.

But most of this benefit – $2.4bn – was
accrued in non-Bt fields.

This `area-wide suppression’ effect is presumably true of
chemical pesticides, too. An organic farmer with weedy,
pest-infested fields is contaminating his neighbours’ fields with
weeds and pests, or to put it another way his neighbours are
contaminating him with crop protection. Who’s the free rider?

But the brilliant thing about Bt crops, of course, is that
because the toxin is made inside the plant, you can only encounter
it if you eat the plant, so the general insect fauna is unaffected.
It can therefore thrive, unsprayed.

Higher profits for farmers means lower costs for consumers
(think about it: competition can drive prices lower and effectively
pass on the extra profits as savings). So GM crops are leading to
higher yields which means ploughing less land, cheaper food and
more insect life, which means more bird life.

Will somebody please remind me why my government still cravenly
accepts a total ban on the growing of these crops in my country at
the behest of so-called `green’ groups? It is a disgrace.

I now walk out of restaurants if they say they do not serve GM
food and I tell them why.


By Matt Ridley | Tagged:  rational-optimist