An upfront story of November's American Agriculturist (now on the press) tackled three top crop production issues – herbicide-resistant weeds, insecticide-resistant bugs, and – for some farmers – GMO contamination. They were hot topics of the recent GMO 101 research tour hosted by Penn State University's College of Ag Sciences. Here's a quick look at what'll be covered in the magazine feature:

Good news…bad news
Bt hybrids helped solve developing European corn borer resistance problems with soil insecticides. "They've worked so well that corn borer populations were driven down to almost an endangered species," says Entomologist John Tooker.

RESISTANCE CHEWED DOWN: Penn State's John Tooker shows the evidence of severe western corn rootworm damage on Bt corn found in Pennsylvania this year.

Soil insecticide use was greatly reduced. Other crops, tomatoes, for instance also benefited from the ECB decline.

Bt toxins also helped reduce Western corn rootworm populations. The transgenic trait allowed expansion of continuous corn. While it boosted grower flexibility, it was at the expense of crop rotation and Integrated Pest Management.

Then rootworm resistance to Bt hybrids targeting ECBs began developing due to weak gene expression. This year, damaging populations of rootworms suspected to be resistant to some Bt strains turned up in three Pennsylvania counties and threaten farmers growing continuous corn.

To complicate the situation, he contends Bt hybrids targeting below ground pests indirectly increased use of neonicotinoid insecticide-treated seed. Evidence is growing that non-target influence of neonicotinoids and residue build-up in soils are contributing to the decline of pollinators.

Seed treatments also kill other beneficials, including brown beetles that control slugs – Pennsylvania's biggest insect problem in corn and soybeans in conservation tillage, adds the entomologist. "This isn't a GMO problem," stresses Tooker. "It's a product management problem."

The herbicide resistance dilemma
Weeds evolved and naturally mutated on their own long before crop tolerance was

genetically engineered into corn and soybeans. Concern over triazine- and ALS-resistant weeds predated glyphosate and GMO crops, points out Dwight Lingenfelter.

How herbicides are used "cause weeds to evolve," explains the Penn State weed specialist. "Economics and convenience drive farmer decisions and led to the demise of integrated weed management."

Most of today's herbicides are 20 years old. Most new products are simply reformulations or premixes of existing active ingredients.

"That's why we strongly recommend integrated weed management strategies in addition to using herbicides with at least two modes of action," adds the weed specialist. "We need new modes of action. But today, if a company comes up with one, it takes many millions of dollars and at least 10 years to get it to market."

How farmers use GMO technology is the problem – not the technology itself, insists Lingenfelter. Because of the growing weed resistance problem to herbicides, he says there's already industry talk of mandating management resistance via seed technology use agreements.