WASHINGTON D.C.: Due to persistent shortages of agricultural chemicals that threaten yields, U.S. farmers have cut back on using common weedkillers, looking for substitutes to popular fungicides, and changing their planting schedules.

Amidst already tight global grain supplies caused by the Ukraine war, which is reducing the country's exports, spraying herbicides and using less-effective fungicides increase the risk for weeds and diseases to affect crop production.

Chemical dealers, manufacturers, farmers and weed specialists said shortages disrupted their production strategies and raised their costs.

Shawn Inman, owner of distributor Spinner Ag Incorporated in Zionsville, Indiana said supplies are the tightest in his 24-year career, stating, "This is off the charts. Everything was delayed, delayed, delayed," he said, as quoted by Reuters

Shortages further reduce options for farmers battling weeds resistant to glyphosate, the key ingredient in the commonly used herbicide Roundup, which has been used for decades in the U.S.

Prices for glyphosate and glufosinate, another widely used herbicide sold under the brand Liberty, jumped more than 50 percent from last year, dealers said, increasing the profits of companies such as Bayer, BASF and Corteva.

According to the U.S. Agriculture Department, farmers and food companies are concerned about agribusinesses hiking prices for chemicals, seeds and fertilizers to boost their profits, rather than just due to supply and demand factors.

The agency has launched an inquiry into competition in the sector, but some watchdog groups said it is moving too slowly.

The COVID-19 pandemic, transportation delays, a lack of workers and extreme weather have been blamed for shortages by agrichemical companies, adding that fertilizers and some seeds are also in short supply globally.

BASF, which manufactures glufosinate, told Reuters that supply issues will continue into next year.

Scott Kay, vice president of U.S. crops for BASF, said, "It is going to take more time than what our customers, farmers and retailers would have thought," as reported by Reuters.

Tennessee farmer Jason Birdsong said that after waiting months to receive the herbicide Liberty he ordered from Nutrien Ag Solutions, he abandoned plans to plant soybeans on 100 acres, as he received less than half his order for 125 gallons, adding that he planted corn, instead.

Nutrien said numerous factors have shut the supply chain during the COVID-19 pandemic, and is providing alternative solutions to customers.

Meanwhile, dealers said the rising popularity of a Corteva soybean variety, Enlist, is further adding to glufosinate demand.

Iowa corn and soy grower Brent Swart said due to short supplies, he is using less glyphosate in the mix of chemicals he sprays, but he does not expect this to reduce yields.

"There is definitely a different feel to this year. We have never seen as many supply issues," he stressed, according to Reuters.