The fires have been on farmland in areas around Newton Abbot, Teignmouth, Paignton and Dawlish.
All the incidents involved a number of fire crews attending the scenes for long periods of time.
Safety advice has now been issued to farmers on how to reduce the risk of arson, including preventing easy access and installing security.
Dawlish cliffs could collapse at any time
Newton Abbot MP says action needed
Two murders in Cornwall
They're not linked
Councillor owes more than £3,000 in council tax
They are paying it back at £130 a month
Vape causes extensive damage to Exeter bin lorry
Pleas for residents to watch whats going in bins
‘Torbay first’ plea in council shake-up consultation
'We need to ensure that what we submit is right for Torbay'
Police appeal following Yelverton burglaries
Keys and a digital camera taken
