Measurement of semiochemical release rates with a dedicated environmental control system

Authors: Zhu, Heping; THISTLE, HAROLD - Us Forest Service (FS); Ranger, Christopher; ZHOU, HONGPING - Nanjing Forestry University; STROM, BRIAN - Us Forest Service (FS)

Submitted to: Biosystems Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/29/2014
Publication Date: 1/1/2015
Publication URL: http://handle.nal.usda.gov/10113/61295
Citation: Zhu, H., Thistle, H.W., Ranger, C.M., Zhou, H., Strom, B.L. 2015. Measurement of semiochemical release rates with a dedicated environmental control system. Biosystems Engineering. 129:277-287.

Interpretive Summary: Applications of semiochemicals to attract or repel insects in specific areas or to disrupt their mating have increased rapidly as a pest management strategy. Because of their safer and have minimal non-target impacts, they have been integrated with other disciplines to provide reliable and eco-friendly pest management tools for effective pest control. It is a goal of pest management programs to optimize performance of semiochemical release devices, thereby promoting predictable and efficient use of semiochemicals with minimally adequate release rate for controlling a specific insect population and activity over a specified time frame. However, predictions of their longevity are currently hampered due to a lack of sophisticated methods to accurately monitor how the primary variables affect the semiochemical release rate. A controlled environmental system that was able to independently control the air temperature and relative humidity was developed to accurately measure semiochemical release rates. Test results verified that measurements of release rates of three semiochemicals in the controlled environmental system were more precise, consistent and repeatable than measurements under field conditions. Consequently, precise quantification of semiochemical release rates for different temperatures and relative humidities with the new system will provide baselines for modelling semiochemical longevity under field conditions, for deployment of semiochemicals, and for optimization of design of semiochemical release devices.

Technical Abstract: nsect semiochemical dispensers are commonly deployed under variable environmental conditions over a specified time frame; however, predictions of their longevity are hampered by a lack of methods to accurately monitor and predict how the primary variables affect the semiochemical release rate. Herein a system was constructed to precisely determine semiochemical release rates under environmentally-controlled conditions. Three dissimilar types of solid matrix, passive emission semiochemical dispensers (P339 Sirex, Beetleblock-MCH, W230 terpinolene) were selected to verify the system capabilities. The rate of weight loss for each semiochemical was measured inside a 0.11 m3 air sealed reservoir. Each product was tested at five ambient temperatures and three relative humidities. The system maintained temperatures at their set points within ±1.0°C and relative humidities within ±0.4%. Weight losses for the relatively large P339 Sirex dispensers were linear over the test period exposure to the air; weight losses for the smaller Beetleblock-MCH and W230 terpinolene dispensers fell sharply during the first 10 hours of exposure and then were linear with exposure time. Test results demonstrated that release rates of the three semiochemicals at the linear stage increased exponentially as ambient temperature increased, and those rates were not apparently affected by relative humidity. Compared to release rates measured under field conditions, determination of semiochemical release rates was more precise and consistent in this dedicated, controlled environmental system. Semiochemical release rates measured with this system will provide a baseline for predicting performance and useful lifetime of semiochemical devices deployed for pest management in agriculture and forestry.