Wight Salads uses biopesticides for tomatoes under 30ha of glass in Havant. Pests include whitefly, aphid and spider mite as well as a range of fungal and bacterial diseases.
Dr Phil Morley, a technical agronomist for Wight Salads, said: "Our experience of biopesticides has been quite varied. Some work well, others not so well.
"What works well in a laboratory may not work so well in real life and it's difficult to get optimum conditions in a glasshouse. You have to think of the whole holistic picture with biopesticides. They are not a single-hit solution but need to be used with a great deal of thought. If we want to make sure these are successful we will need to pay close attention to grower education and hand holding, at least initially."
Morley said growers often thought of biopesticides in the same way as pesticides. The sector needed a collective "mind shift" to take the issue into a new "paradigm", he added.
But growers would have to pay for advice or learn from their experience on the nursery - there was no Govern-ment guidance and there were no "freebies".
"The only problem with Horticultural Development Company-funded research, which we've nevertheless benefited from, is it's not specific to your problem. You have to work out the cost benefits of employing advisers and it's much harder for smaller growers with limited time and resources."
Roger White, whose Westhorpe Flowers & Plants in Boston is half organic, warned growers not to expect "silver bullet" solutions with biopesticides on vegetables. He said: "Biologicals are totally different from conventional chemicals and won't offer the silver bullet. Controls vary and you seldom provide 100 per cent control. We believe the potential lies in using a combination of controls or a combination of predators."