Why are dust formulations usually NOT used outdoors on a large scale?

Dust formulations are typically not used outdoors on a large scale primarily because they may drift away from the target area. When applied, dust can become airborne due to wind or other environmental factors, making it challenging to ensure that the product remains concentrated in the intended application zone. This drifting not only reduces the effectiveness of the treatment on the target pest but also raises concerns about potential non-target exposure and environmental impact.

In contrast, other options do not accurately describe the primary concern with outdoor dust applications. For example, measurement accuracy is manageable with proper techniques and tools, and effectiveness can vary based on conditions rather than the formulation itself. Additionally, while dusts may attract some non-target species, this is not the principal reason for limiting their outdoor use on a broader scale. The significant risk of drift and inappropriate application is the main factor that guides the decision to avoid large-scale outdoor use of dust formulations.