What is a disadvantage of both EC and ULV formulations?

The correct answer highlights a significant concern associated with both emulsifiable concentrate (EC) and ultra-low volume (ULV) formulations. These types of pesticides often use solvents that can be chemically aggressive. As a result, they have the potential to cause deterioration of materials such as rubber or plastics, which are commonly used in hoses, gaskets, and parts of spraying equipment. This deterioration can lead to leaks, equipment failure, and increased maintenance costs, which poses risks during operation and impacts the efficacy of pesticide application.

Understanding that solvents are integral to the formulation of EC and ULV products helps in recognizing that while the efficacy of these formulations may be high, the durability of the applicator's equipment can be compromised if proper materials aren't used or if regular maintenance isn't conducted. This understanding reinforces the importance of selecting appropriate materials when working with these formulations to ensure safe and effective pesticide application.

In comparison, the other options discuss challenges that may not be universally applicable to both formulations or are specific to certain conditions. While agitation requirements and handling difficulties can vary based on specific products and circumstances, the chemical interactions highlighted in the correct answer represent a more consistent issue across both EC and ULV types.