Even before Bollgard II varieties first came on the market in 2003, North Carolina State entomologist tested these plants for efficacy and found that all did an excellent job of producing internal toxins, and ultimately protecting cotton plants from bollworms. Now, the evidence is not so clear.

Over a number of tests, in several locations in the early 2000s, North Carolina researchers consistently found less than four percent yield loss in plots planted in Bollgard II varieties, compared to plots with no bollworm protection. “We put Bollgard II under heavy insect pressure in the early years, and it held up well,” says North Carolina State University Entomologist J.R. Bradley.

In recent years, he says, a number of new players have entered the ring, resulting in a number of different Bollgard IIs. Adding the Bollgard II genes to new varieties has produced some inconsistent yield losses. For example, Bradley says in tests last year, Stoneville 6611 had 10 percent boll loss at one site and only five percent loss at a different location. In some tests there have been zero yield loss and in others over 10 percent, he says.

“There is a lot of difference in how these Bollgard II varieties protect themselves. It's not like an insecticide you get out of a can or bottle, which gives you consistent results, if application is timed right and other label instructions are met.

Bollgard II is a living organism that produces its own internal toxins, and some have shown to be more efficient than others,” Bradley explains.

These plants are producing proteins and some are more efficient than others. “If you look at a broad spectrum of people, it's the same concept — some of us are more efficient than others at producing proteins that become toxins and help us fight off various threats to our health, according to Bradley.

Bollgard II is the second-generation of insect-protected cotton developed by Monsanto. This technology contains two different insect-control genes, compared to the single insect-control gene in its predecessor Bollgard.

“Bollgard II cotton is expected to provide the grower with additional benefits including a broader spectrum of insect-control, and increased defense against insect-resistance, as well as similar agronomic advantages as its predecessor, Bollgard cotton — including increased yield and lint potential, improved insect control, reduction in input costs, savings in time, and reduced pesticide sprayings,” according to Robb Fraley, chief technology officer for Monsanto, manufacturers of Bollguard II.

“Growers should add some additional consideration for the cotton varieties they plant. Certainly, they should consider the adaptability to their farm and land and the yield and quality potential is critical. But don't ignore the difference in susceptibility to insects that is inherent in Bollgard II varieties because these are not the same,” Bradley stresses.