Capillaries as controlled release devices for insect pheromones and other volatile substances-A reevaluation : Part II. Predicting release rates from Celcon and Teflon capillaries.

A predictive model developed for the release rates of volatile materials from glass capillaries was invalid when tested with Celcon fibers used commercially in pheromone-based insect control strategies. Several factors which might explain the differences between the predicted and observed rates are discussed, and it is hypothesized that the topography of the fiber lumen is the major factor causing the observed rates to deviate from the predicted values and the large variation in rate from fiber to fiber. This hypothesis was tested using Teflon capillary fibers with both smooth and rough lumen walls and shown to be valid. This indicates that commercial hollow-fiber pheromone formulations can be improved both in efficiency and cost by careful selection of fiber material, improvement in fiber manufacturing, and the use of a predictive model in formulation design.