# pest\_perc This parameter controls the amount of pesticide removed from the surface layer in runoff and lateral flow relative to the amount removed via percolation. This parameter is only important if pesticide transport is simulated. {% hint style="info" %} The lower *pest\_perc*, the lower the concentration of the pesticide in runoff. If *pest\_perc* = 1.0, the surface runoff will have the same pesticide concentration as the percolate. {% endhint %} --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://swatplus.gitbook.io/io-docs/introduction-1/basin-1/parameters.bsn/pest_perc.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.