Invasion of the Superweeds – The Agricultural Arms Race –

Blake Hurst farms in northwestern Missouri with his family, raising corn, soybeans and greenhouse crops.

We used to control weeds by cultivating. Three triangular shovels ran between each row of crops, rooting out weeds. We were left with weeds that had tap roots and tough stalks, which slid around the shovels. Sort of a forerunner of herbicide-resistant weeds, when you think about it. We’d cut the escapes with a hoe, which was my summer job.

We used to control weeds the old-fashioned way — with hoes.

Then, we had an outbreak of shattercane, a grass closely related to grain sorghum, which seemed to thrive on the crop protection chemicals we had at the time. Shattercane seeded so profusely that the cultivator was ineffective, and would grow back from below the ground after we cut it with a hoe. A plant that was hoe resistant.

Then, we had Roundup, which ended the threat from shattercane. But some of those wily weeds have evolved to defeat Roundup, and the war between man and weed goes on. No different than it has since the beginning of time.

We haven’t noticed a large problem with Roundup-resistant weeds on our farm because we only use Roundup every other year, and we use crop protection chemicals with different modes of action to lessen the chance of resistant weeds. We will no doubt see an increase in resistant weeds, and we’ll perhaps have to lengthen the time between applications of Roundup to maintain its effectiveness.

None of this is surprising. Of course weeds evolve, and certainly some farmers have overused a wonderful tool, just as doctors have over prescribed antibiotics. Being a technological optimist, I assume that weed scientists and crop geneticists are working overtime to solve the problem. Martial metaphors are disturbing to those who imagine farming as a pastoral stroll with Gaia, but we’re in an arms race with weeds, and thus has it always been.

Invasion of the Superweeds – Room for Debate Blog –

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