Speaking yesterday at an open day where different bracken controls methods were demonstrated, he said the incentive for farmers dealing with the plant now came from the effect on single farm payments and how it reduced potentially productive acreage.
There is also the possibility of getting a Scottish Rural Development Programme grant of up to 200 per hectare for bracken destruction.
"Controlling bracken is an ongoing problem for land managers," said Campbell. "It reduces the area of grass available. It causes problems at gathering when sheep can be hidden and can be a haven for ticks.
"It can so easily take over if farmers sit back. In addition to the loss of grazing and the disease risk, farmers should also think about the legal side of things," said referring to possible penalties under EU rules on keeping land in good agricultural and environmental condition in claiming for bracken infested land.
Asulox, the main chemical used in treating bracken is currently enjoying a short reprieve from a European Union threat to remove it from the market because of the risk involved in using it.
Politicians will return to the issue in the Autumn but Campbell said he hoped it would continue to be allowed to be used as it played an important role in keeping bracken at bay.