What term describes the effect of two or more pesticides applied together that is greater than the sum of their individual effects?

The term that describes the effect of two or more pesticides applied together that is greater than the sum of their individual effects is known as synergism. In the context of pesticide application, synergism occurs when the combined action of the pesticides enhances their effectiveness, leading to a more potent result than if the pesticides were applied separately. This phenomenon can be particularly beneficial in pest management, as it may allow for lower dosages of each pesticide to be used while still achieving the desired level of control.

In contrast to synergism, antagonism refers to when the combined effect of the pesticides results in a lesser effect than what would be expected from their individual actions. Additivity describes a situation where the effects of the combined pesticides equal the sum of their individual effects, rather than amplifying or diminishing it. The term "combination" is more general and does not specifically imply the enhanced effectiveness seen in synergism. Therefore, synergism is the most accurate term for describing the enhanced efficacy when multiple pesticides are used together.