Effect of Kaolin on Fitness and Behavior of <I>Choristoneura rosaceana</I> (Lepidoptera: Tortricidae) Larvae

Abstract

The mechanisms by which kaolin, a clay particle film formulation, affects the fitness and behavior of larvae of obliquebanded leafroller, Choristoneura rosaceana (Harris), were investigated. Feeding experiments tested kaolin as a physical barrier versus a physiological toxin for larvae that consumed kaolin applied either to apple (Malus spp.) leaves or mixed in artificial diet. Behavioral experiments tested the effects of kaolin applied to apple leaves on neonate dispersal and leaf rolling by third and fourth instars. When larvae fed on apple leaves sprayed with kaolin, mortality and time to pupation of larvae increased significantly, whereas pupal mass significantly decreased. When larvae consumed kaolin mixed into an artificial diet, however, the effects on mortality, pupation time, and pupal mass were negligible. There may be minor physiological effects from consumption because male time to pupation was delayed for larvae fed diets containing the highest concentration of kaolin. In behavioral experiments, neonate larvae dispersed more quickly off plants covered with kaolin than control plants, and kaolin delayed the construction of leaf shelters by third and fourth instars. We showed that the effects of kaolin on C. rosaceana larvae are primarily physical, causing changes in dispersal and rolling behaviors and as a physical barrier to feeding.

The potency of minerals to reduce oriental fruit fly infestation in chili fruits

“…A previous study on using kaolin against a fruit fly found that it can operate as a tactile deterrent, lowering the time female Rhagoletis pomonella (Welsh) spends on treated fruits ( Leskey et al, 2010 ). Another study discovered that the leafroller Choristoneura rosaceana (Harris) neonate larvae dispersed more quickly from plants treated with kaolin ( Sackett, Buddle & Vincent, 2005 ).…”