The Stihl equipment was taken from Millburn Place in Dumfries between 9.30 am and 10.15 am last Friday.
Constable Ross Jack at Dumfries said: “This appears to have been an opportunist theft which happened whilst the worker left the machine to carry out another task. The blower is valued at around £500.
“We want to hear from anyone who may have been in the Millburn Place area on Friday and who may have seen anyone making off with this machine.”
Police at Dumfries can be contacted through 101.