Effects of kaolin clay on flea beetles and other pests and non-target insects on tatsoi

Kaolin is a natural aluminium silicate clay material of interest for insect pest management. We conducted field and laboratory experiments to assess effects of kaolin (Surround WP ® ) on pest and beneficial insects. In a field experiment with tatsoi greens ( Brassica rapa subsp. narinosa), kaolin applications, particularly at high rate (50 g AI L −1 ) reduced shot hole damage, as well as captures of crucifer flea beetles, striped flea beetles, aphids, and leafhoppers on sticky cards to levels comparable to an insecticide industry standard, while maintaining plant vigour. In the same field experiment, some kaolin treatments reduced captures of carabid beetles on some dates, but parasitic wasp captures on sticky cards were unaffected. In laboratory experiments, kaolin treatments did not cause mortality of two-spotted spider mite, green peach aphid, or diamondback moth larvae, but diamondback moth larvae avoided and consumed less cabbage foliage treated with kaolin. Our results suggest that kaolin can reduce crucifer and striped flea beetle damage on Brassicaceae crops like tatsoi and may provide similar protection against diamondback moth on Brassicaceae crops, while posing low hazard to non-target beneficial insects.