Recent figures from pesticides watchdog BASIS revealed 5,920 staff in agriculture had undergone formal training while 4,292 had done continuing professional development since 2001. The figures for amenity were 143 and 321 respectively.
"We need to up our game, not necessarily to have thousands of people qualified but more than we have now to take the standards, expertise and knowledge gained from training into our businesses," said Singleton.
"You could say, with all the pressures with budgets and bad weather, why bother with training? But the businesses that have gone forward are those that carry out best practice, training and qualifications," he added.
"They are using training and certification to give themselves a competitive advantage. Staff feel more empowered because they are knowledgeable and can give clients better service."
Singleton said the industry is "greatly disappointed" the Sustainable Use Directive did not spell out the need for compulsory training and standards. BALI technical director Neil Huck added that nobody takes any notice of voluntary initiatives.
Environment Agency senior adviser Jo Kennedy said the government was deregulatory in ethos, so if compulsory measures were wanted, the Amenity Forum would probably have to take a "quasi-regulatory" role.
Weedfree contracts manager Richard Stow favoured compulsory professional registration for all users but suggested the Amenity Forum should focus more on urging clients to demand best practice from their contractors.
JSD Rail managing director Danny Hayward said: "Herbicides are so cheap there’s no incentive to use them carefully. Glyphosate used to cost £78 per five litres but a typical wage was £25. Raising prices would be a good, but unpopular, driver."