Why is it discouraged to tank mix insecticides with different modes of action (MOAs)?

Tank mixing insecticides with different modes of action (MOAs) is discouraged primarily because it can contribute to the development of insecticide resistance. When insects are repeatedly exposed to the same type of active ingredient, or to different insecticides that affect them in similar ways, they can develop a resistance to those products over time. This reduced susceptibility can lead to the ineffectiveness of current insecticide options and may ultimately necessitate the use of more toxic products or increased dosages to achieve the desired control, which can have negative implications for pest management and environmental health.

Using products with different MOAs can potentially provide better control of a broader spectrum of pests, but if done indiscriminately, it can accelerate the resistance phenomenon. Integrated pest management strategies often emphasize rotating modes of action to help delay resistance development. Thus, proper management practices are critical to maintain the efficacy of insecticides over time.