What is the consequence of incorrectly calibrating a spreader?

Incorrectly calibrating a spreader can lead to several significant consequences. When a spreader is not properly calibrated, the amount of pesticide applied can vary considerably from the intended dosage. This inconsistency can result in reduced pesticide effectiveness, as too little product may not adequately control the targeted pests, while too much can lead to ineffective treatments and potential resistance.

In addition, improper calibration can increase material costs because the user may end up using more product than necessary to achieve the desired level of control or, conversely, may need to apply multiple treatments to compensate for ineffective initial applications.

Furthermore, there's an environmental impact to consider. Over-application can lead to runoff and the potential contamination of nearby water sources, harming aquatic ecosystems. Conversely, under-application might not only fail to control invasive species but could also allow for their spread, further affecting the environment.

Thus, the collective consequences of not calibrating a spreader correctly encompass reduced effectiveness, increased costs, and environmental concerns, making "All of the above" the most comprehensive and accurate answer.