SpotOn to roll out thermal tool to measure inversions

FARGO, N.D. -- They call it the SpotOn Inversion Tester, and a North Dakota State University Extension Service pesticide specialist says it could be helpful for farmers applying volatile herbicides -- especially dicamba -- on sensitive crops like...

Andrew Thostenson, an NDSU Extension Service pesticide specialist, demonstrates the SpotOn Inversion Tester -- a tool designed to collect and calculate temperature inversions at the farm level that can lead to spray drift and off-target crop damage from herbicides such as dicamba. Photo taken Nov. 29, 2017, in Fargo, N.D. (Forum News Service/Agweek/Mikkel Pates)

FARGO, N.D. - They call it the SpotOn Inversion Tester, and a North Dakota State University Extension Service pesticide specialist says it could be helpful for farmers applying volatile herbicides - especially dicamba - on sensitive crops like soybeans.

The device made by Innoquest, Inc., of Woodstock, Ill., will be marketed starting in mid-March at various dealers in Minnesota, North Dakota, South Dakota and Montana. The list price is $375, which includes a carrying case.

The tool is designed to help farmers who want to comply with label requirements on temperature inversions, a phenomena that affects spray drift. It also is helpful for recording temperatures at boom height.

Andrew Thostenson, an NDSU Extension Service pesticide specialist, has had a prototype since November 2017 and has been talking about it in farm meetings this winter. Thostenson says it offers promise for measuring temperature inversions at the field level - a complement to area-wide automated inversion stations at various North Dakota Agricultural Weather Network locations.

"It's really quite accurate, it's quite sensitive, and I expect that it won't be terribly expensive," Thostenson told an audience this winter. "We've used these sorts of things at NDSU and we're using a similar system on these towers, but they're not terribly portable."



Bill Hughes, Innoquest's founder, president and owner, hopes he'll be selling "thousands" of the devices. He's in the process of rolling out the device and has developed it with the consultation of several university officials, including Thostenson. Hughes is an agricultural engineer, trained at the University of Illinois, and he started the company in 1993.

Innoquest has 20 employees. It manufactures and markets test instruments for agriculture - both for researchers and farmers. Hughes says that the company initially made products that were marketed under other company names.

In 2008, Innoquest launched its own brand name - "SpotOn" - started making an electronic, semi-automatic sprayer nozzle calibrator. The company sells thousands of the calibrators all over the world, including Minnesota, the Dakotas and Montana, Hughes says.

After the dicamba-soybean problems arose in the South in 2016, Hughes heard from Bob Wolf, owner and president of Wolf Consulting & Research LLC at Mahomet, Ill. Wolf had been talking with Thostenson and various university specialists, asking about tools for testing temperature inversions.

Hughes told Wolf he didn't knew of any testing devices that farmers could use to indicate temperature inversions but that he could invent one. Temperature inversions are conditions where the temperatures above a farm field are warmer than the temperatures at the plant level. The condition can allow herbicides or other sprays to drift off-target as a kind of fog - sometimes for miles.

Essentially, the device is a collapsible pole that measures 1 meter long.

One end has is a temperature sensor, surrounded by "shades" that protect it from direct sunlight or other sources of heat radiation. The operator holds it at two levels - one meter from the ground and three meters. They "wave or stir" it gently for about 20 seconds to get an accurate temperature reading.


At the other end is an electronic display. If the temperature is higher at 3 meters than at 1 meter, there is an inversion and spraying is typically not recommended, Hughes says.


To keep production cost down, the device doesn't have GPS or a way to upload the data to a computer. Hughes says the user simply uses a smartphone to photograph the readings and record the time, date and even location.

"It's part of the metadata for the photo," he says.

The device's temperature accuracy is developed and verified to the specifications of the National Institute of Standards and Technology.

Thostenson says farmers should consider acquiring one of the device, but also should pay attention to NDAWN readings, as well as time of day. He says the technology could be placed on spray rigs, but it has to be properly shielded.

He says even a difference of a half a degree or degree may be a significant inversion.

"I would think anything with a half a degree or more (difference) would make me feel uncomfortable" spraying, he says. "We have observed 4- or 5-degree separations on a really intense day, and I guarantee it doesn't matter what you put into the atmosphere, it's not going to go where you want it to go. Only the big spray droplets will get there."


Volatile pesticide gases create a "constant source of pesticide being emitted into the atmosphere," and the cloud can move laterally until the inversion breaks. "It volatilizes over a three or four-day period and can be impacted by multiple inversion events."

Hughes says people with questions should contact There is a listing of dealers at , where inventories are not not yet n place. The company phone is 800-637-1623.

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