Caroline McChesney, 49, denies being the person responsible for the spate of incidents between June and September last year that began months after her husband, David, had died.
Glasgow Sheriff Court heard doctor John Maclean's cars were damaged with repeated flat tyres, abuse scratched on his car, and abuse daubed on his garage door and garden gate. He told the jury he was sent cards with messages including "How are you at putting out house fires".
Dr Maclean, 38, from Hyndland, Glasgow, was one of David McChesney's doctors up until the patient died in October, 2012.
He gave evidence at the trial of McChesney, of Lennoxtown in East Dunbartonshire, who was also a patient at the Turret Medical Practice in Kirkintilloch where Dr Maclean is a partner.
She is accused of causing Dr Maclean and his wife Rebecca fear or alarm between June 10 and October 26, 2013.
The court was told of a number of incidents last year, including Dr Maclean's tyres being let down and an obscenity scratched on the bonnet of his car.
Dr Maclean said that, after another incident, his car was so badly damaged it had to be scrapped. His wife's car was also scratched, its Mercedes badge ripped off and the tyres slashed. The doctor said his mother-in-law's car was also targeted when his wife borrowed it for a few days.
Dr Maclean told the jury that on June 22 last year a card arrived that said: "Going on holiday contact you wene [sic] back p.s your a dab hand with a pump lol".
Procurator fiscal depute Richard Hannay asked: "What did you think when you saw this card?" The doctor replied: "I was angry, I was frightened. I realised that this appeared to be a concerted campaign. We were very concerned as to who might be doing this and what their motive might be."
Dr Maclean said he installed CCTV and began parking his Mercedes 10 minutes away from his house but that the tyres were "violently slashed" once again.
The court heard that another card was received by the doctor that said: "Thinking of spiceing [sic] things up a little. How are you at putting out house fires??? (better than hiding cars ha ha)".
The witness said he was "very upset" and reported the matter to police, who recommended the fire brigade doing a risk-assessment.
The jury were also told that further obscenities were sprayed on Maclean's garage door, back gate and neighbour's bins.
Some instances of the car being vandalised by a hooded person was caught on CCTV, clips of which were shown to the jury.
Dr Maclean said that in September last year, he saw someone passing his house with a hood up whom he thought was the person responsible and followed them.
He said he watched someone he believed was a female getting in to a car and speeding off and was later told that the car belonged to McChesney.
Mr Hannay asked Dr Maclean how he felt when the police told him who owned the car, and he replied: "Devastated."
Dr Maclean told the jury he had been one of the doctors involved with Mr McChesney before he passed away, and saw the accused after her husband's death as she frequently came to the surgery.
He said he had no knowledge of any complaint from the family about Mr McChesney's care.
The doctor said Mr McChesney was diagnosed with cancer before he started working at the practice in 2009.
He said: "I remember visiting him in the later stages of his illness at his home and I remember seeing him in the final days of his life as a routine visit."
The trial before sheriff Martin Jones, QC, continues.