Shares of Tractor Supply fell more than 16 percent on Thursday, their worst day since April 28, 2000, when the stock lost 17.24 percent.
The retailer cut full-year revenue and earnings forecasts, and also gave third-quarter earnings-per-share guidance of between 65 cents and 67 cents, below previous expectations of 72 cents.
"With our customers generally being fiscally conservative, we believe many of them have responded to the economic uncertainty by reducing their purchasing patterns in some of our key geographic regions," said CEO Greg Sandfort in a press release.
Wedbush Securities downgraded Tractor Supply to "neutral" from "outperform" on Thursday.
"Weakness in agricultural communities is apparent due to three consecutive years of declining farm income to the lowest level since 2009," said analyst Seth Basham. Tractor Supply sells everything from hardware and tool products to recreational clothing and footwear, serving a largely rural customer base.
Meanwhile, Guggenheim Securities maintained its "buy" rating on the stock, though analyst Steven Forbes lowered his price target to $90 per share.
"We believe the company's recent headwinds pertain more to macro-related issues (than micro) and fully expect operating momentum to reaccelerate into 2017," he said.
Tractor Supply has been trading below its 200-day moving average since August 4.