One of the cool things about agricultural technology is that
it gets both more effective and safer over time.
Agricultural chemical manufacturers are developing products
that have much shorter lives—that break down far more quickly and don’t persist
in the environment nearly as long as earlier products.
“Contrary to the one-dimensional view of pesticides as
broad-spectrum and persistent, recently developed insecticides are highly
selective for insect pests,” write the authors of a report on potential pesticides.
I chatted with a South Illinois corn and soy farmer last
week. His 1,500-acre family farm has virtually stopped using insecticides—which
were extensively used a generation ago.
He said the use of insect-killing chemicals on his farm has
been made unnecessary by stacked traits that put varieties of the Bacillus thuringiensis into the seed—so the
plant itself prevents insect attack and chemical sprays are unnecessary.
It has the additional benefit of impacting only those
insects actually feeding on the crop. Other insects in the environment are not
impacted.
He still uses herbicide, but generally in just two
applications annually. His farm has gone to no-till agriculture, and he applies
glyphosate herbicide once to kill off the spring growth, and most years one
second application later in the year is all that is necessary. Sometimes the
second application is avoided.
He said that when he started farming half a century ago, the
chemicals were heavily used and were dramatically toxic or caustic. His overall
use of chemical additives is down dramatically, and his soil is healthier than
it was, he said.
This farmer said he’s a believer in technology. It made his
farm profitable, and something his two adult sons are interested in taking
over.
One of the interesting features about some new insecticides
is that they’re patterned after natural products. Bacillus thuringiensis is a natural soil-born bacterium. By
inserting the effective sections of Bt’s genome into agricultural plants, the
plants are provided with the ability to protect themselves.
Some researchers are now looking at another natural product,
tarantula venom, as a potential agent for pesticides.
Here is the original paper on that.
Here is the Science Daily report on the research.
It turns out tarantula venom isn’t only scary to humans, but
very effective against the cotton bollworm and other insects. And they don’t
have to be stung; they can be killed from eating it.
There are cautions here, though. since some of these
biopesticides or “botanicals” may actually be more toxic in the environment
than their synthetic cousins.
“Synthetic pesticide use has been the dominant form of pest
control since the 1940s. However, biopesticides are emerging as sustainable
pest control alternatives, with prevailing use in organic agricultural
production systems,” write the authors of the paper, “Bioinsecticide-Predator
Interactions: Azadirachtin Behavioral and Reproductive Impairment of the
Coconut Mite Predator Neoseiulus baraki.”
They warn that while natural and approved for organic
farming, azadirachtin has certain toxicity issues. The authors note that 70 percent of synthetic
insecticides have natural analogs, but that the natural ones are not always
safer.
Azadirachtin, which is approved for organic farming, is
derived from the seeds of the neem tree. One concern is that its use as an
insecticide can screw up the natural relationship between problem insects and their
natural predators—since the predators are also impacted by the insecticide.
The used of the product “may lead the predators to leave the
area, compromising the biological control,” and ultimately making farmers more
reliant on chemicals.”
Clearly, this stuff is complicated, but it’s heartening that
as more study occurs, we’re understanding relationships better and developing better agricultural controls.
© Jan TenBruggencate 2015
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