Why should heavy rain forecasts be avoided during pesticide application?

Heavy rain forecasts should be avoided during pesticide application primarily because of the increased risk of runoff. When heavy rain occurs shortly after pesticides have been applied, it can lead to a significant wash-off of the chemicals before they have had a chance to effectively enter the target plants or soil. This runoff can carry the pesticides into nearby water bodies, potentially contaminating them and harming non-target organisms, including aquatic life and beneficial insects.

Additionally, runoff can reduce the efficacy of the pesticide treatment, resulting in less effective pest control. Since proper application is crucial for both effectiveness and environmental safety, avoiding pesticide application during periods of heavy rain forecast mitigates these risks and helps ensure that the pesticides perform as intended while protecting the surrounding ecosystem.