Speaking at the Centre of Excellence for UK Farming conference in Warwickshire, Dyer urged EU policy-makers to back a science-based approach to approval or risk damaging food production.
"The cost and bureaucracy involved in bringing a new crop protection product to market in Europe are becoming prohibitive," he said.
Researching, developing and registering each new active ingredient takes at least nine years, involving up to 200 scientific studies into health and environmental impact, at a cost of some EUR300m, he added.
"Continued innovation in plant science and crop protection is vital to meet food security imperatives. But no research-based sector of industry can operate effectively, or make long-term investment decisions, in the face of spiralling development costs and continuing uncertainty over the EU registration process."
Chemicals Regulation Directorate senior herbicide specialist Ingrid den Hoed told the British Crop Protection Council Annual Weed Review last month: "There are fewer active substances leading to increased pressure on remainder, which will themselves be subject to restriction. Grass and broad-leaved weed control in break crops will be increasingly difficult."
She urged "a more whole farm approach" to crop production, improved rotations, and the breeding of more competitive cultivars and herbicide-resistant crops.
Active substances already removed from the market, through not having being submitted for registration under EU directive 91/414 - 67%
More than one food item in 40 registers above the Maximum Residue Level, although the rate is falling, according to European Food Standards Agency.
It tested for 834 pesticides in nearly 68,000 samples across the EU. The rate was found to be significantly higher in foods originating outside the European Economic Area - 6.9 per cent, compared with 1.5 per cent of foods from within it.