Coupland, 48, of Crieff, made two false VAT repayment claims between March 2011 and November 2012.
He claimed his computer had crashed and he had lost vital information which meant his VAT returns ended up being for the wrong amounts.
But the jury found him guilty on two charges of being "knowingly concerned in the fraudulent evasion of Value Added Tax".
Coupland was found guilty of submitting false repayment claims for £124,172 between 1 March 2011 and 6 June 2012.
He was also found guilty of submitting a false claim for £37,056 between 1 June and 30 November 2012.
Cancelled meetings
A trial heard that Coupland, sole director of WDR Coupland (Produce) Ltd, aroused suspicion because of the large sums he claimed to have made in net value sales.
HMRC compliance officer Chrystal Symons told the court that she became suspicious about the company when Coupland claimed to have sold over £2m worth of potatoes in two months.
She told the trial: "You would need to have a large company to be doing that amount of business."
A raid on Coupland's home and business was carried out to search for the company's records, but he repeatedly avoided meeting investigators.
The court was told that Coupland had cancelled a number of interviews at the last minute as the investigation was carried out.
Coupland told that court that on one occasion he was unable to meet the tax inspectors because he had been stranded on a business trip to sell seed potatoes in Nigeria.
Sheriff William Wood deferred sentence for the preparation of reports.
