Police in Lincolnshire are warning farmers to be vigilant after a number of thefts of tractors in the south of the county.
They are also appealing for the public to ring in any suspicious activity like tractors being on the roads in the evening.
Three machines have been stolen in the South Holland area in recent weeks.
A JCB fast track, registration AE08LMF, worth about £90,000 was taken from a farm in Crowland between Friday 9 April and Monday 12 April. It also had a fertiliser spreader worth about £15,000 with it.
A John Deere tractor, registration FX08LJC, worth about £65,000 was taken from a farm at Shepeau Stow, Whaplode Drove, overnight on 25/26 March.
Another John Deere tractor, registration FX06 EZW, was taken from a farm off Bidder Road, Donington, overnight on 21/22 March.
Head of Spalding Vehicle Crime Unit Dave Sargent said: "This is a real emerging trend and we need farmers and the public to be vigilant to prevent more thefts and to help us catch these criminals.
“If anyone sees tractors on the road in the evenings, possibly in convoy with another vehicle, then please call the police with the registration details.
“It doesn't matter if it hasn't been stolen, you won't be wasting our time, we'd rather check and if we start getting calls like this we have a much better chance of getting out there and making an arrest. These types of crimes are a huge blow to farmers and the local rural economy as a whole and we need to work together to tackle the problem.”