What term describes two or more pesticides that cannot be effectively mixed together?

The term that describes two or more pesticides that cannot be effectively mixed together is "incompatible." Incompatibility can arise due to various chemical reactions that prevent the pesticides from forming a stable solution. This can lead to separation, precipitation, or degradation of the active ingredients, reducing their efficacy and potentially posing risks when applied. Understanding pesticide compatibility is crucial for applicators to ensure they achieve the desired effectiveness without adverse reactions that could harm crops, beneficial organisms, or soil health.

In contrast, "synergistic" refers to a situation where two substances work together to produce an effect greater than the sum of their individual effects, which does not apply to incompatible mixtures. "Compatible" indicates that the pesticides can be mixed successfully without issues, directly opposing the concept of incompatibility. Lastly, "neutral" does not pertain to the mixing properties of pesticides and is not a relevant term in this context.