Biochemical Biopesticides: Minerals/Other
Minerals play a key role in a wide range of biopesticide applications that can be divided into three categories:
- those that create barriers that keep pests from plant tissues and/or impact pathogen water supply
- those that deliver physical impacts such as smothering or abrasion
- those that act as an inert carrier for companion biopesticides.
Kaolin clay is a good example of a biopesticide that creates a physical barrier between insects and plant tissues. Kaolin acts as a repellent that coats the plant surface and makes it unsuitable for insect feeding and/or egg laying. Kaolin also breaks off in small particles that attach to insects, agitating and repelling them.
Potassium silicate is another example of this type of biopesticide, which also serves as a dessicant to soft bodies insects and mites.
Diatomaceous earth (DE) is an example of a mineral biopesticide that combats insect infestations through abrasion. DE contains fossilized microscopic plants, giving the compound a sharp surface that cuts through insects’ exoskeletons, a process that leads to dessication of the insect.
Mineral oils are used to smother insect pests in nesting stages.
Minerals are also used as inert carriers for companion biopesticides. In these applications, minerals are included in formulations to deliver or enhance pest control agents, but the mineral itself is considered an inert ingredient. Examples of these mineral types include montmorillonite, attapulgite, kaolin, and talc, all of which have physical structures that allow biopesticides to be carried on them, often in powder or granular formats.