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United States Department of Agriculture

Agricultural Research Service

Research Project: BIOLOGICAL CONTROL OF SWALLOW-WORTS, INVASIVE WEEDS OF THE NORTHEASTERN UNITED STATES

Location: Biological Integrated Pest Management Unit

Title: Swallowwort dispersal: seed tracking under field conditions

Authors
item Stokes, Courtney -
item Ditommaso, Antonio -
item Milbrath, Lindsey
item Mohler, Charles -
item Whitlow, Thomas -

Submitted to: Proceedings of Northeastern Weed Science Society
Publication Type: Abstract Only
Publication Acceptance Date: December 16, 2013
Publication Date: January 6, 2014
Citation: Stokes, C.A., Ditommaso, A., Milbrath, L.R., Mohler, C.L., Whitlow, T. 2014. Swallowwort dispersal: seed tracking under field conditions. Proceedings of Northeastern Weed Science Society. p. 59.

Technical Abstract: Vincetoxicum rossicum (pale swallowwort) and V. nigrum (black swallowwort) are invasive, perennial vines found in natural areas of the northeastern United States and southeastern Canada. Seeds of both species are primarily wind-dispersed in the form of achenes with an attached coma. For this study, “seed” will refer to the complete achene-coma unit. To better characterize the dispersal of these species by wind, a tracking study was initiated in October 2013. Research took place in hay fields near Aurora and Ithaca, NY. Seeds were placed individually in a clothespin attached to the end of a 1.27-cm-diameter PVC pole. A string was attached to the clothespin and used to allow researchers to open the clothespin while crouched down approximately 2 m from the pole, in an effort to minimize wind disturbance. Release heights of 0.75 and 2 m were used. Wind speed was recorded at the moment of release for each seed using a hand-held anemometer, and distance traveled was measured using a tape affixed to the base of the PVC pole. Seeds were recovered and returned to the lab, where seed weight and settling rate were recorded. Settling rate was obtained by dropping individual seeds down an 8-cm-diameter clear plastic tube 1.22 m long. Falling time in seconds was converted to settling velocity in meters per second. Tracking studies took place a minimum of three times at each location, and seed shadows were generated for each release event. Not all seeds were recovered; 4% of the total seeds released were observed traveling too high or far for researchers to follow. Of the recovered seeds, distance traveled ranged from 0.14 to 86.73 m. It is expected that release height, wind speed, settling rate and seed weight will affect distance traveled; data are being analyzed to test this hypothesis. Additionally, models will be tested for fit. Potential models could include exponential, inverse power, or Clark’s 2Dt functions.

Last Modified: 10/1/2014
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