What might indicate a pesticide is outdated or ineffective?

A pesticide that changes color or settles at the bottom of its container is a strong indication that it may be outdated or ineffective. This suggests that the chemical composition of the pesticide has deteriorated or that it has begun to break down. The efficacy of pesticides relies on their chemical stability; if the formulation is altered, it may not perform as intended when applied.

In contrast, the other characteristics mentioned do not necessarily indicate a pesticide's effectiveness or status. For example, gel-based formulations are commonly used and do not imply obsolescence. Bright labels may be a marketing choice rather than an indicator of the product's efficacy. Additionally, a long shelf life in stores is generally a sign of good product stability and does not inherently mean the pesticide is outdated. Thus, observing changes in appearance or settling of the product is a more reliable sign of potential ineffectiveness.