For many business owners, getting the most out of staff is a perennial problem. In the case of fruit farmers, perhaps perennial is the wrong word: workers show up only for the summer harvest. In a couple of weeks they will be heading home, usually to a university course somewhere in eastern Europe.

Tough work for the fruit pickers, the business is also a headache for the owner, who must offer a pay scheme that both satisfies minimum wage laws and motivates workers in an industry in which slacking is an understandable temptation.