Impact of Electrocution on Shoot and Tuber Vitality of Yellow Nutsedge (<i>Cyperus esculentus</i>)

Abstract

Cyperus esculentus is an invasive perennial sedge that can cause huge losses in arable crops. Current control strategies are based on combinations of cultural, mechanical, and chemical measures, repeated over years. Recent commercial releases of safe innovative electric weeders, offer promising alternative opportunities for controlling perennial weeds with high energy/high frequency electricity. To evaluate the effect of a single electrocution application on the efficacy of C. esculentus control, field experiments were performed in two locations in Belgium. Two electric weeding devices were evaluated: Zasso XP300, delivering a high-frequency, phased direct current (maximum voltage of 7000 V and maximum power output of 2000 W per square meter of green biomass, driving speeds between 1.1 and 3.0 km·h−1), and Rootwave Pro, delivering high-frequency alternating current (maximum voltage of 5000 V and power output between 7.5 and 10 kVA, treatment duration of 2 s). The impact of various technical (driving speed and voltage), biotic (clone and growth stage), and abiotic parameters on electrocution efficacy was evaluated. Plant responses to electrocution were evaluated by examining the vitality of treated C. esculentus mother tubers and shoots. Both devices were ineffective at mother tuber control, regardless of their burial depth (−5 cm to −15 cm), but were highly effective against aboveground shoots with reductions of vitality of up to 91% and 100% after a single pass with Zasso XP300 and Rootwave Pro, respectively. Maximum reductions were obtained when electricity was delivered at low speed (1.1 to 1.5 km·h−1) and on 5-leaf shoots without heat or water stress. Remarkably, the lowest efficacies were found on water-stressed soils at the time of application. Voltage had no effect on the degree of C. esculentus control. The efficacy of electricity was not affected by clone, irrespective of electric weeding device. Electrocution is a useful and effective control method within any integrated control strategy for controlling emerged shoots. However, as C. esculentus mother tubers are not affected by a single treatment, season-long repeated treatments are needed to exhaust the mother tubers.

Keywords

• mother tuber
• prevention
• thermal weeding
• electrophysical weeding
• voltage
• driving speed