Selection of devices: release devices are selected for evaluation based upon customer input. Please contact us if you would like us to evaluate a particular device or if you have data you would like to share via this webpage.
Deployment and measurement: Measurements can be labor-intensive, so evaluations have been made in the three locations at which we are stationed: Missoula, MT, Pineville, LA, and Susanville, CA. These locations also provide us with a wide range of environmental conditions under which releaser performance can be measured. We attempt to evaluate all devices in Pineville and then again at the location nearest to their expected field deployment. We also attempt to evaluate devices during the period of their expected deployment, but other considerations (personnel availability, head-to-head testing of devices, extended deployment schedules, etc.) also play a role. So far, only gravimetric measurements have been made to estimate releaser performance. Semiochemicals for which this is insufficient (e.g., Ips pheromones which gain weight over time) have not been evaluated. Typically we measure device weight every day during the first week of deployment, as passive devices usually release more chemical during this period. Later in their deployment, we typically measure devices every week.
We usually evaluate devices both in full-sun and full-shade. Exceptions are devices that leak rainwater into their chemical reservoir; these are only deployed where they can be protected from rainfall. Full-sun evaluations in Pineville and Susanville also include full exposure to rainfall, which sometimes causes devices to gain weight. This can be caused by water intruding into the device or water gathering on the outside in folds, etc. When an individual releaser gains weight at a particular measurement time, that datum is deleted from the dataset. If the weight gain was the result of water accumulating on the outside of the releaser (i.e., the next dry weighing period appears normal), then we continue to use the individual releaser. If the releaser’s semiochemical load has been compromised, it is discontinued from the evaluation. In Missoula, a canopy was deployed so that devices could receive full-sun for most of the daylight hours while also protecting devices from most rainfall.
Meteorology: Weather stations were placed at our Pineville and Missoula sites. In Susanville, we relied upon weather data gathered by the USDA-FS at the same site. Temperature is provided as a mean for each period between releaser weighings (14:00 to Noon).
Units: data are gathered as weight lost and reported on a per day basis (g or mg lost per day) regardless of the number of days between measurements. Temperature is reported in degrees Fahrenheit.
Data Summaries: provided to quickly give information on each device. They may or may not be useful for a particular deployment scenario and, as shown by the charts, are not useful in many cases due to the pattern of semiochemical release. Mean elution rates (weight losses) are provided for time periods thought to be relevant for field deployment (e.g., 30 d) and for the duration of time over which the device may be considered to perform reasonably (determined by eye from the chart). It is noted, however, that release patterns over time are not amenable to simple averages as a satisfactory indicator of releaser performance. We provide a mean daily weight loss that was determined from the simple, mathematical average daily weight loss. This average has not been weighted and may overestimate the total load of a device.
Charts: provided as line graphs for direct viewing and included in summary sheets on the webpage. They show results for the duration of the experiment and are based upon their accompanying data file (*.xls format). These are meant to provide the observed pattern of device performance on a mean weight loss per day basis. Simpler evaluations (e.g., mean weight loss for the duration of the deployment) are crude, as shown by the dynamic patterns observable in the charts.
Summary Sheets: Summary sheets are provided as pdf’s and are meant only as a quick guide. Our contact information and files (*.xls) containing the weight/temperature data are provided for evaluations by those interested in this additional information.