Washington, November 24 A new study that analyzes insect resistance data from five continents has determined that existing theories and strategies can be used to predict, monitor, and manage insect resistance to Bt crops.

According to lead author Dr. Bruce E. Tabashnik, "Resistance is not something to be afraid of, but something that we expect and can manage if we understand it."

"Dozens of studies monitoring how pests have responded to Bt crops have created a treasure trove of data showing that resistance has emerged in a few pest populations, but not in most others," he said.

"By systematically analyzing the extensive data, we can learn what accelerates resistance and what delays it. With this knowledge, we can more effectively predict and thwart pest resistance," he added.

The researchers concluded that the refuge strategy (growing non-Bt crops near the Bt crops) can slow the evolution of insect resistance by increasing the chances of resistant insects mating with non-resistant ones, resulting in non-resistant offspring.

They added that crops that are "pyramided" to incorporate two or more Bt toxins are more effective at controlling insect resistance when they are used independently from crops that contain only one Bt toxin.

The researchers also said that resistance monitoring can be especially effective when insects collected from the field include survivors from Bt crops.

They concluded that DNA screening can complement traditional methods for monitoring resistance, such as exposing insects to toxins in the lab.

Despite a few documented cases of field-evolved resistance to the Bt toxins in transgenic crops, most insect pest populations are still susceptible, they added.

With Bt crop acreage increasing worldwide, incorporating enhanced understanding of observed patterns of field-evolved resistance into future resistance management strategies can help to minimize the drawbacks and maximize the benefits of current and future generations of transgenic crops. (ANI)