March 20, 2023

New system sprays weeds on sight

TREMONT, Ill. — A vision-based targeted spraying system that’s under development was featured at Precision Planting’s recent winter conference.

The Symphony Targeted Spraying System will be in its second year of in-field testing this spring.

The vision-based spraying system uses camera technologies and artificial intelligence to vary spray rate based on weed size and pressure, or to spray herbicide only where weeds are present, saving chemicals. This system can be retrofit onto a farmer’s existing sprayer.

“When we flat-rate apply based on an entire field level decision-making, we’re trading off costs for weed control and we’re deciding both rate and chemistry and that’s ultimately based on a budget. In many cases, we do that sometimes four months ahead and we prepay,” said Jason Stoller, Precision Planting product manager.

“We’re deciding based on what we believe is going to be a right budget that’s going to do a good enough job for whatever we experience four months from now.”

The goal to optimize weed management is to select chemistry that provides the best chance of control. The problem is those chemistries are expensive, especially when two or three modes of action are needed.

“So, the goal with optimization is have our cake and eat it, too, to be able to select the best chemistries, multiple modes of action, but do that in a way to some way minimizes the cost to make the return on investment make sense,” Stoller said.

“We’ve come to the conclusion that the only way to address the compromise between weed control and costs is with technology to intelligently apply the right rate of herbicide and only where it’s needed.

“The game totally changes when you give the sprayer the ability itself to see or detect weeds in your field and then vary the rate based on what is actually detected.”

Weed Detector

With the Symphony Target Sprayer in spot spray mode, when weeds are detected, the nozzles are on and when it doesn’t detect weeds the nozzles are off.

“We also have a mode that we’re designing and developing called auto rate. You set your minimum rate and your maximum rate on your 20/20 and then the system automatically varies the rate based on two categories — weed density and weed size,” Stoller said.

“It now gives us the ability to do exactly what the label is driving us towards for best control, but we can do it in a way that our costs are at a manageable level.

“The system we’re designing also has the capability of dual product independent control. With our vision system, those vision modules are applying a contact herbicide based on what the system detects.

“The system is designed where you can also flat rate applying or blanket applying a residual. This gives you the ability when you’re pre-applying to contact targeted application though the vision system and also blanket apply residuals.”

Field Trial Results

Data was collected from several initial field trials last spring with a prototype. In a field test with the Symphony targeted sprayer across 215 acres, 970 gallons were used to control weeds. A conventional sprayer would have used 4,300 gallons on that same field.

“That’s a 77% reduction in herbicide use for this application. Not only that, but we refilled on time in what would have been six fills,” Stoller noted.

In a 70-acre field, only 225 gallons were applied pre-plant for full weed control compared to 1,394 gallons that would have been used across those same acres with a conventional sprayer — an 84% reduction in herbicide usage.

In a third field, applying 32 ounces of Enlist and 40 ounces of Liberty post-plant in a soybean field with the targeted spray system there was an 81% reduction in herbicide use.

“If I had blanket-applied this field it would have been $36 an acre and it actually cost us $7 an acre using the targeted spray system. That was one field. If this was 2,000 acres we would have saved $58,000 in once year in one pass,” Stoller said.


Vision Scout is an additional feature included with the Symphony Targeted Spraying System.

Vision Scouting is maps and reports that the 20/20 is automatically generating based on the Vision system while spraying. An example is a weed density map indicating where weed pressure is low and high that can be used for future reference.

Tom Doran

Tom Doran

Field Editor