Updated April 27, 2021:
This project involves evaluating the effectiveness of the Weed Zapper™ on common weeds in Missouri soybean production systems. The Weed Zapper™ is a Missouri-made product that consists of a front-mounted electrocution
boom and rear-mounted PTO-powered generator. The boom must contact the plant for electrocution to occur, and up to 15 kV of electricity can be translocated through contacted plants.
In 2020, our Mizzou Weed Science team evaluated the efficacy of weed electrocution on marestail (horseweed), common and giant ragweed, waterhemp, and a mix of common weedy grasses like giant and yellow foxtail and barnyardgrass. Soybean injury and yield response were evaluated following contact with the electrocution boom.
Preliminary findings include:
• Better weed control was obtained when weeds were higher above the soybean canopy.
• Waterhemp control was greater than 80% if electrocution occurred at R5 or R6 soybean growth stages.
• Electrocution was effective on marestail (horseweed) and common and giant ragweed, with general trend that the taller the plants, the more effective the control.
• Control of grassy weeds was less effective than broadleaf weeds. The growing point of grasses is below the boom, and these species tended to produce new growth after electrocution.
• Weed electrocution at the R1 or R2 soybean growth stage may not be an effective timing as in most cases, few escaped weeds have emerged above the soybean canopy at that time of the season.
In a deliberate, “worst case scenario” where the electrocution boom maintained constant contact with the upper 2 to 3 inches of the soybean canopy, up to 17% visual soybean injury was observed. In some instances, this injury resulted in soybean yield loss when compared to the controls.
These results indicate the importance of having a height differential between the weed escapes that are being electrocuted and the soybean canopy, and in keeping the boom as high as possible with this implement.