Maintaining healthy pollinator populations is in growers' own interests, a panel of experts told last month's Fruit Focus exhibition.
Better pollination could increase the market value of Gala apples alone by more than £5m a year, University of Reading research fellow Dr Michael Garratt claimed. This would put the value of insect pollination to the UK fruit industry at more than £430m a year.
"The quality of some apple varieties, as well as of strawberries, is affected by the way they are pollinated, but there is a decline in abundance and diversity of pollinators," he said.
Garratt's research has shown that Braeburn apples, in common with strawberries, are largely pollinated by bumblebees, whereas the main pollinators of Cox, Bramley and Gala are solitary bees.
And while fruit set in both Cox and Gala drops by up to two-thirds when pollinators are excluded, this also negatively affects the size of Gala, though not of Cox, he said.
Grower Oliver Doubleday, chairing the discussion, pointed out: "The quality and quantity of pollen deposition also affects the size and quality of cherries."
Centre for Ecology & Hydrology researcher Dr Richard Pywell said measures such as bee strips "have a more beneficial effect on simple landscapes where there is little in the way of species-rich ancient grassland". But he added that such measures are not the sole answer to pollinator decline, because the "rarer bees tend to be specialists on ancient grassland, which needs protecting".
On the vexed question of neonicotinoid insecticides and their impact on pollinators, Pywell said: "There is no conclusive evidence either way. It needs proper monitoring in the field and that isn't happening. We need a good non-neonic control before we decide they have no role in agriculture, but everyone is using neonics (in oilseed rape)."
East Malling Research entomologist Dr Michelle Fountain advised growers: "Think of what pollinators need, such as nesting sites, forage and over-wintering. Don't be too tidy, and think about what you are spraying and when."
Pollinator impact Cider apple orchards
Richer, more diverse pollinator communities are at the edge of fields, resulting in higher fruit set on adjacent trees, Lancaster University PhD student Alistair Campbell has concluded from monitoring pollination in Herefordshire cider apple orchards.
Campbell found significantly lower fruit set when pollinators were excluded.
Speaking at last month's Bulmer's growers day, he said: "Solitary bees are responsible for 60 per cent of visits, but they need food sources before trees come into flower, for which wild flowers, particularly dandelions, are important."