Kaolin acts as a very effective carrier

Kaolin acts as a barrier that irritates insects and disguises the host plant by coating it with a ghostly white film. Insects are apparently unable to recognize plants treated with kaolin. It is most commonly used against a wide variety of pests on apple and pear trees. Also, kaolin can be used to control Japanese beetles, tarnished plant bugs, thrips, leafhoppers, cucumber beetles and Colorado potato beetles on vegetable crops. Kaolin must be applied as a preventative to be effective and cannot control a pest that is already established. It is non-toxic and can be applied up to the day of harvest. It can also be used as an anti-caking agent in the production of fertilisers. Kaolin is also used as an inert ingredient in many pesticide formulations.