While effective herbicide options to control the most challenging weeds dwindle, industry is increasing efforts to discover new technologies to better control weeds. While a new herbicide such as glyphosate to control waterhemp is unlikely, we have other options coming along in both the chemical and mechanical realms. This article will review two of the new options on the market for managing weeds: targeted spray solutions and weed electrocution devices.

Targeted spraying

Several companies are marketing targeted spray solutions that turn nozzles on to treat emerged weeds as sprayer cameras detect them. The primary interest with these is to target emerged weeds for burndown or postemergence applications, reducing chemical use and — ideally — costs.

In addition, a reduction in chemical application should also benefit the environment, due to reduced risk of runoff or off-target exposure. Research with these systems frequently shows substantial reductions in pesticide use while maintaining sufficient control of weeds. These systems fit best in fields with low weed pressure following effective preemergence herbicide treatments.

While targeted spray operations offer some benefit, they come at a cost and some risk. They are more expensive than standard sprayer setups, and some require a per-acre subscription fee when the targeted spray option is turned on. Targeted spray applications generally have lower maximum application speeds compared to traditional sprayers.

Risk is primarily associated with efficacy of herbicide treatments. What is the applicator’s personal risk balance between applying more product vs. potentially missing weeds?

Finally, any spray application is only as effective as the herbicides are against the target weed species. The value of this technology depends on the availability of effective herbicides, which resistance is threatening.

Weed electrocution

This weed management strategy is generally more of a weed “cleanup” or “rescue” strategy. Weed electrocution is most effective on annual broadleaf weeds such as waterhemp but can be effective on some weedy grasses as well. The weed electrocution devices on the market target large weeds extending above the crop canopy and that are far off-label for herbicide applications.

The tool’s objective is to control the plants present — and reduce production of viable weed seed. This presents a huge opportunity to make strides toward the goal to minimize weed seed production in crop fields. This can simplify future weed management and slow herbicide resistance development. It is ideal for use in fields with scattered weeds above the crop canopy, as populations that are too dense will reduce plant contact with the toolbar.

Like other non-chemical strategies, electrocution comes at a cost and presents some challenges. The equipment can be expensive, dangerous to operate, and it runs slowly.

Farmers also need to allow weeds to grow quite large before this equipment is most useful. This allows for better efficacy on the weeds themselves and a greater differential between the crop and the toolbar. Accidental contact with the crop may result in injury that affects yield. Electrocution is more of a “rescue” operation used on fields where weeds got the upper hand on management tactics used earlier in the season, rather than something planned on at the start of the growing season.

I have confidence that technology will continue to develop new, innovative solutions to manage herbicide-resistant weeds. I don’t believe anything will ever be as simple as the one- or two-pass glyphosate applications of the late ’90s and early 2000s. However, the challenges associated with different weed management strategies are necessary to stay ahead of the weeds and continue to produce high crop yields. Each farmer will have to determine which new strategies work best for them and their farming operation, but the first step to improving weed management is knowing the options available. You can learn more about new weed management strategies here.

Anderson is an Iowa State University Extension field agronomist.