Resistance Management:
An important characteristic of the pest program represented in Fig. 5 is that NO insecticide is used against the same pest in two consecutive generations. Why is this important? Because it represents a sound resistance management approach designed to conserve the efficacy of new insecticides against our key pests. By not using an insecticide in successive generations of a pest, the selection pressure for resistance is reduced. Also note that we do not use Assail in one CM generation and Calypso in the next. These products are in the same class and have the same mode-of-action. If we used Assail in first CM generation and Calypso in the following generation, selection pressure for resistance to the entire class would be exerted against both generations, thus increasing the chances of resistance development.
How should you treat insecticides that have activity against multiple pests? The principle to remember is to NOT use a product for control of one pest at one time of year and then against a different pest later in the growing season if the first pest will also be exposed to the product. For example, we use Rimon against CM in the spring as an ovicide treatment (petal fall) we area also controlling LR. We could consider using Rimon again against LR in the summer but this would mean the same product was used against the same pest on two consecutive generations. Instead, we switched to the use of Intrepid in the second CM generation and got the added bonus of LR suppression. The best resistance management tactic is to use an insecticide against a pest as few times as possible. For this reason, the use of MD is a very good resistance management tool because it typically reduces the use of insecticides for CM control.