Farmers in the USA are cutting back on their usage of common weedkillers, looking for substitutes for popular fungicides and changing their planting plans due to ongoing shortages of agricultural chemicals, according to a Reuters report.

Reducing herbicide usage and turning to less-effective fungicides increase the risk of weeds and diseases, which could hit crop production at a time when global grain supplies are already tight as a result of the ongoing conflict in Ukraine affecting exports from the country, the 27 June report said.

Interviews with more than a dozen chemical dealers, manufacturers, farmers and weed specialists had shown that shortages disrupted US growers’ production strategies and had raised their costs, Reuters wrote.

Shawn Inman, owner of distributor Spinner Ag Incorporated in Zionsville, Indiana, said supplies were at their tightest level in his 24-year career.

“This is off the charts,” Inman said. "Everything was delayed, delayed, delayed."

Shortages further reduced options for farmers battling weeds that had developed resistance to glyphosate, the key ingredient in the commonly used Roundup herbicide, after decades of overuse in the USA, the report said.

Prices for glyphosate and glufosinate, another widely used herbicide sold under the brand Liberty, have increased more than 50% compared to last year, according to dealers.

The US Agriculture Department has said it had heard from farmers and food companies concerned about whether agribusinesses were increasing prices for goods like chemicals, seeds and fertiliser to boost profit, not simply due to supply and demand factors. The agency has launched an enquiry into competition in the sector, and some watchdog groups have said it is moving too slowly.

Agrichemical companies, meanwhile, say the shortages are due to the COVID-19 pandemic, transportation delays, a lack of workers and extreme weather. Fertiliser and some seeds are also in short supply globally.

German chemical and biotech giant BASF told Reuters that it did not expect the supply situation to improve significantly next year.

“It's going to take more time than what our customers, farmers and retailers would have thought,” Scott Kay, BASF vice president of US crops Scott Kay said.