Resistance Management


rows 2Integrated Pest Management, or IPM, is a crop protection strategy directed towards preserving beneficial insects and having minimal impact on the environment. Bt insecticides such as DiPel or Xentari, are ideal tools for growers intent on carrying out effective and efficient IPM.

Entomologists and IPM specialists cite the following benefits of Bt insecticides:
• Very low impact on beneficial insects.
• Avoidance of secondary pest problems.
• Not toxic to mammals, bees or beneficial predatory mites.
• No preharvest interval required after application.
• No restrictions on use.
• Resistance to Bts slower to develop than resistance to chemicals – new or traditional.

Bts aren’t intended to replace traditional chemicals, however. Both traditional chemicals and Bts have a place in the grower’s pest control toolbox. Bts can control pests just as traditional chemicals, but also provide added benefits such as resistance management and maintaining beneficial insects. Indeed, Bts can revive the life cycle of a traditional chemical by preventing over-use.

Perhaps the best way to think of Bts is as a valuable piece to the puzzle. Just as using a single traditional chemical wouldn’t make any sense, Bts are best used as one element of a comprehensive program that accounts for the many variables they are able to manipulate. In fact, the best time to use Bts may be when a new chemical is made available. Combining the two makes for a sustainable program – sustainable both environmentally and economically – and will manage resistance, keeping all products working effectively through many years of profitable production.

Pest control experts point to insect resistance as one of the biggest problems today’s growers face. Whether an insect, weed or pest population, many more of the older, traditional products aren’t working as well as they used to. And new ones must be managed wisely to retain their efficacy through time.

Because of their unique modes of action, Bt insecticides have long been the cornerstone of pesticide resistance management programs around the world. Rotating chemicals helps avoid resistance problems, but an even better approach is applying Bt insecticides at strategic points in the crop season. This can alleviate the need to rely on traditional chemicals and oftentimes improve their efficacy later on.

Bts have much more complex modes of action than their traditional counterparts, which means it is somewhat more difficult for insects and plant pathogens to develop resistance. This is especially true when used in an IPM program. It’s a win-win, because not only do you suffer fewer resistance problems, but you reap specific benefits such as reduced crop protection costs.

application timing

For example, a grower should use a Bt early in the season. It not only costs less than the chemical, but offers a high kill rate early in the season while infestation levels are low, and also helps maintain beneficial populations. In mid-season, traditional chemicals maintain a clean field and increase the spectrum of activity. A Bt application prior to harvest will then bring the benefit of clean crops at packout, the lowest possible preharvest interval, minimized chemical residue, and diverse modes of action to maximize the product life cycle.