Aerial view of field with biosolarization tarps

What are pesticides and how are they used in agriculture?

Pesticides are an essential part of farming and are defined as any substance or mixture of substances intended for preventing, destroying, repelling, or mitigating any pest that can be harmful to cultivated plants or to animals.

When are pesticides harmful?

Many conventional pesticides pose a health risk for humans. Soil fumigants are one type of pesticide used to protect crops in Western agriculture that have been broadly identified as being toxic and/or carcinogenic. Despite mandated protective equipment, application methods, and access restrictions, exposure risks remain for agricultural workers and communities near fumigation sites.

How is WCAHS addressing these issues? 

WCAHS investigators are evaluating biosolarization as an alternative to traditional soil fumigation. Instead of toxic conventional pesticides, biosolarization uses solar heating and microbial activity to create soil conditions that are lethal to many pests but safe for humans. Field research is being conducted in California almond orchards, which account for nearly all of the nation’s almond production.

When almond processing residues, such as hulls and shells, were amended into the soil to trigger microbial activity, various organic acids accumulated in the biosolarized orchard soils, which were shown to inactivate plant parasitic nematodes. These acids are generally far less toxic than conventional fumigants, which benefits orchard workers, neighboring communities, and the environment.