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General Resistance Management Strategies


The greater the selection pressure on a pest population is, the more pressing the need for resistance management. However, even with low selection pressure, strategies should be put in place to reduce the chance of resistance developing. Depending on the selection pressure, resistance management strategies can range from simple, general practices to very specific multi-product/multi-crop guidelines that consider such factors as product usage, pests, mechanism(s) of resistance, alternative products, and fit with IPM and ICM programs. In either case, some combination of general resistance management strategies often form the backbone of the evolving strategy:
  • Build proven preventive practices into an Integrated Pest Management System.


  • Use pesticides only when necessary (based on economic thresholds).


  • Rotate to a pesticide with a different mode of action (MOA). This may be necessary with sequential applications to the same crop, or when spraying a rotational crop. Some products with the same mode(s) of action can be applied sequentially in the same crop or the rotational crop without development of resistance while others should not be applied sequentially unless other effective control practices are also included.


  • Apply pesticides which are effective on the potentially resistant species in tank-mix, prepacks or sequential applications which include multiple modes of action. Avoid use of pesticides which are ineffective on resistant target species in tank-mix or prepacks.


  • Combine as many resistance management strategies as possible when applying maximum label rates of pesticides because high rates enhance the selection pressure for resistance. Conversely, do not apply rates lower than those recommended for a particular pest species because this favors survival of the stronger individuals in the pest population. Adhere to label rates for the specific pest, crop, conditions, and location - each registered rate is carefully determined based on field trials.
    • Insect


  • Use preventative control where resistance is known to be occurring. Preventative control is the use of a pesticide(s) which prevents the pest from developing, as opposed to curative control which is not used until the pest or evidence of its presence (such as plant symptoms) has been observed.


  • Follow label directions for optimum timing relative to the growth stage of the target pest. Application to pest populations that are beyond the optimum timing (e.g. large weeds, late instar insect larvae or disease in the epidemic phase) can speed the development of resistance.


  • Follow label directions for proper application method (carrier type, volume, use of adjuvant, etc.) Ensure that application equipment is properly calibrated and maintained.


  • Where practical, use spot treatments, barrier treatments or banded treatments to better target pest populations or the zone where pest control is required.


  • Combine pesticides with cultural practices - these include:

    • Plant pest-resistant crop varieties
    • Maintain optimum crop growth through proper fertilization, irrigation, etc. - a healthy crop is more competitive with weeds and often less susceptible to disease and insect attack
    • Rotate crops, particularly those with different pest problems
    • Use tillage at times for weed control (where erosion is not a problem)
    • Use biocontrol if available
    • Control alternate hosts of insects and diseases
    • Clean tillage and harvest equipment before moving from fields infested with resistant species
    • Scout fields regularly to respond quickly to changes in pest populations and, in the case of insects, to monitor the presence of natural enemies.