South Australia’s growing mouse plague is threatening crops across the state during the critical seeding season.

It’s led to farmers lobbying to change laws for greater access to stronger baits.

As the number of vermin continues to rise on land crops, many farmers are concerned they will lose a large portion of income this season if the population is not controlled.

Fifth-generation farmer Kalvin Tiller said he was spending an extra $25,000 on baiting alone.

“Because there’s an increase in mouse numbers we’ve been baiting everything, in the past we haven’t necessarily done that,” Mr Tiller said.

“In the past you might bait 500 to 1000ha of land every year but this year we will do the whole 3000.”

Growing a mixture of crop including wheat and lentils, the 43-year-old said he would be in favour of farmers having access to stronger bait.

“We’re crossing our fingers and hoping the 25mg bait is going to do a good enough job controlling the mouse population and hopefully we don’t have to re-sow,” he said.

“The 50mg strength bait does a better job at controlling the mice population from my observation.

“We should be pushing for 50mg to become usable.”

Agriculture consultant Leighton Wilksch, 48, said he saw “1000 mice” through a thermal camera in his neighbour’s paddock while fox hunting last week.

“I was aware there were elevated numbers of mice,” Mr Wilksch said.

“But after looking at the heat produced by the animals in the paddock I was blown away by the number of mice there were.”

South Australian Researching and Development Institute entomologists are currently travelling across the state undertaking several research projects, after recently observing adult rodents moving into previously sown paddocks.

Zinc phosphide is the only rodent-specific pest control chemical that is approved for use in general cropping in Australia.