PARENT SESSION
Friday, August 11, 8:00-11:30 am
COS 104 - Invasive species VII: prevention, control, and models
Ballroom E, Ballroom Level, Cook Convention Center
Presiders: T Langkilde
Feasibility of ultrasonic control on water chestnut.
Wu, Mei-Yin1, Wu, Jun-Ru2, 1 State University of New York at Plattsburgh, Plattsburgh, NY2 University of Vermont, Burlington, VT
ABSTRACT- Water chestnut (Trapa natans L.) is an annual aquatic plant with floating leaves around a central stem and feathery, adventitious submerged structures. T. natans is native to Southern Europe, tropical Africa and Asia and was first introduced into North America in 1874. Since then, wild populations have quickly become established in many locations within Northeastern United States. T. natans is referred to as a noxious aquatic weed since its aggressive growth nature usually results in a complete coverage of water surface with floating rosettes of leaves. Dense surface mats suppress native submerged and floating plants by shading, successfully colonizing and ultimately monopolizing aquatic habitats. Ultrasound has been documented to effectively damage plant cells and tissues without causing any contamination; this study examined the potential of ultrasound application for Water Chestnut management. Various frequencies and amplitudes of ultrasound waves generated by submerged transducers were applied directly to water chestnut plants. Substantial damages on water chestnut plant cells as well as penetrated petioles were found at the following tested frequencies of ultrasound, 20 kHz, 187 kHz, 469 kHz, 519 kHz, and 2.34 MHz. Among them, 20 kHz ultrasound demonstrated the most significant damages after 10 seconds of ultrasound exposure. A laboratory-scale, effectiveness of ultrasound experiment was conducted under a controlled greenhouse environment. An ultrasound transducer was submerged in water and aimed directly at target plants from underneath. Plant mortality, leave density and seed production were investigated daily as well as water temperature and pH. The mortality rate of water chestnut plants treated with 20 kHz ultrasound was greater than 90%. No seed was produced by the treated plants. This study also examined the impact of ultrasonic control on two fish species, Northern redbelly dace ()Phoxinus eos) and fathead minnow (Pimephales promelas). No significant impact of 20 kHz ultrasound on fish was identified. The results of this study suggested that ultrasonic control has a great potential to successfully eradicate invasive water chestnuts.
Key words: water chestnut (Trapa natans L.), ultrasound, invasive plant