When should protective chemicals be reapplied?

Protective chemicals should be reapplied regularly, depending on weathering, because their effectiveness can diminish over time due to environmental factors such as rain, wind, and UV light exposure. Weathering can wash away or break down these chemicals, reducing their pest control efficacy. Therefore, assessing conditions such as rainfall, temperature, and how long it has been since the last application is crucial for determining when to reapply. Consistent evaluations of these factors ensure that the protection remains effective throughout the growing season.

In contrast, reapplying after every rainfall could lead to over-application and environmental harm, while treating them whenever pests are present might not take into account the reduction in effectiveness from previous applications. Lastly, only applying once a season could leave crops vulnerable if pests arise or if the protective chemicals wear off before the end of the season.