Managed pollination trials reveal additional benefits

Of the more than 16,000 bee species across the world, only a handful are capable of utilisation as managed crop pollinators.  Commercial pollinators include both social species (like bumble and honey-bees) and solitary bees including Alkali Mining Bees and a variety of Leafcutter Bees.  With the recent concerns regarding the decline of honeybee numbers, Norman Collett Ltd and Mid Kent Growers members felt they needed to investigate potential alternatives.  The Red Mason Bee, Osmia rufa, was one of the stronger candidates, being a native of mainland Europe and the UK as well as having been used in semi-managed pollination programmes in the former Eastern Block. 

The Osmia family have also been used with great success in Japan and in the horizon-to-horizon Almond orchards of Southern California.  The pedigree of this small solitary bee is impressive as work in Serbia, Germany, Belgium and now England has shown.  Teaming up with CJ Wildlife (CJW) who is the only UK facility to supply Red Mason Bees for commercial pollination, Nigel Jenner, Norman Collett’s Technical Director, ran a small trial on privately owned Gala orchards in Kent.  As well as expecting the normal things that go along with enhanced pollination delivery, there was a surprise in store for us.  In the trial orchard, as we approached harvest time, the effects of the Osmia bees were quite apparent.  The trees had fruit with fantastic consistency of set, wonderful colour and ripening synchronicity, but the best was yet to be discovered.  Testing the Streif Index, we discovered a couple of anomalies.  The trial orchard was slightly retarded against the control in spite of better colour on the fruit, but the real talking point was the difference in firmness of the fruit.  Our trial orchard was 1.6kg of pressure above the control.  Such a large variance was wholly unexpected, and we felt the need to check against another set of figures in case the large variance was due to poor performance of the control orchard.  We used the averages from 12 other orchards, and still found we were 1.1kg above the mean.  These figures tally with research work done in New Zealand showing a correlation between good pollination and long-term storage potential. 

CJW have spent the last 4 years developing viable propagation systems for Osmia rufa, and can now with confidence say that the technical issues have been cracked.  This means that these gentle, hardworking bees will be available as an orchard management tool for the UK top fruit industry, without the pitfalls of using an imported bumblebee species.  Even without the hassle factor, the statistics are rather impressive.  In trial orchards growing the variety ‘Fuji’, and using Osmia spp., setting rate of the fruit cluster was 74% and that of central fruit was 64.5%, whereas in the control orchards, the figures were 29.8% and 22.9% respectively. Malformed fruit rate was 15.8% in orchards using Osmias, and was lower than that of control orchards at 26.4%. After final fruit thinning, setting rate of the central fruit of the terminal bud was 2.8 times higher than that of the control orchard.  The rate of fruit having seeds over 9 was 33.2-46.0% and was significantly higher than that of control orchards.  Granted, increased thinning means higher labour costs early in the production process, but the potential of cost savings in storage, and the higher production figures are likely to offset this by a considerable margin.