Capillaries as controlled release devices for insect pheromones and other volatile substances?A reevaluation

Abstract

Controlled release formulations are required for the dissemination of behavior-modifying chemicals in insect control strategies. Among the types of formulations that have been used for some time are glass and plastic capillaries. Erratic release rates on field use of such capillaries prompted us to reexamine the release of volatile materials with regard to (1) kinetics of the release, (2) the effect of the vapor-air column above the liquid, and (3) developing a predictive model. Results indicate that the release is not zero order, and that the length of the vapor-air column is a critical factor of the system; a predictive model has been developed that will allow better design of capillary controlled-release formulations.

Efficacy and mode of action of female‐equivalent dispensers of pheromone for mating disruption of codling moth

“…Isomate C Plus dispensers are known to both attract male codling moths (Barrett, 1995; Knight et al , 1999; Stelinski et al , 2004, 2005) and brief exposure within metres of such dispensers strongly habituates the males’ central nervous system (Stelinski et al , 2006a). Given their release rate of approximately 0.1 μg/h (Weatherston et al , 1985), fibres probably disrupt male orientation by competitive attraction without associated habituation (Stelinski et al , 2006a) and, thus, the efficacy of this formulation will be highly dependent on codling moth density. Future improvements to female‐equivalent technologies that may improve efficacy include: (i) improving mechanical application so a greater proportion of applied formulation adheres to tree canopies; (ii) increasing attractiveness of individual dispensers; and (iii) increasing release rate per dispenser (which may require decreasing point source density per area of crop) to increase the likelihood of sensory habituation.…”

Parasitic Wasps Learn and Report Diverse Chemicals with Unique Conditionable Behaviors

“…Cyclohexanone and diisopropyl aminoethanol, which are highly volatile, were formulated in capillaries (0.7 mm i.d. ), and the length of the vapor column above the meniscus controlled release rate (Weatherston et al, 1985). Both 2,4-and 3,4-DNT, which have low volatility, were dispensed from filter paper, and 3-octanone and octanal were dispensed from membrane formulations (Heath et al, 1996).…”

Controlled-Release Dispenser and Dry Trap Developments for Drosophila suzukii Detection

“…The most common semiochemical release devices typically do not maintain a constant release rate, and instead it usually decreases during the season exhibiting first-order kinetics (Weatherston et al, 1985;McDonough et al, 1992;Bradley et al, 1995;Mayer and Mitchell, 1998;Heuskin et al, 2011). From an insect pest management standpoint, it is desirable to have a device that could release the semiochemical at a constant rate (Zhang, 2005).…”

“…From an insect pest management standpoint, it is desirable to have a device that could release the semiochemical at a constant rate (Zhang, 2005). Such constant release devices with zero-order kinetics based on glass capillaries (Weatherston et al, 1985), wax-based formulations (Atterholt et al, 1999), and polyethylene vials/sachets (Pajares et al, 2010) have been tested in the laboratory and/or applied in the field for some insect pest control. Therefore, a dispenser, that is capable of sustainably releasing D. suzukii volatile attractive compounds to the surrounding area, at a constant rate, and over a long period of time needs to be developed in a SWD integrated pest management program.…”