Managing Bees for Delivering Biological Control Agents and Improved Pollination in Berry and Fruit Cultivations.

Targeted precision biocontrol and improved pollination has been studied Europe-wide in the ongoing BICOPOLL-project in a case study aiming at the control of strawberry grey mould Botrytis cinerea, with the biocontrol fungus Gliocladium catenulatum, vectored by honey bees or bumble bees. The joint trial targets strawberry cultivations in the open field, and ideally includes four treatments: untreated control, chemical fungicide, entomovectored biocontrol, and chemical + biocontrol combined. In organic fields, no pesticide treatments are included. The proportion of mouldy berries, and/or the marketable yield of healthy berries is recorded from each treatment, along with other parameters of local interest.  In 2012 such joint field trials were carried out in Estonia, Italy and in the UK – besides Finland, where large areas commercially already use entomovectoring. In 2013 the experiments were expanded to Slovenia and Turkey, and have been continued in 2014. A conservative estimate for Finland is that over 500 ha of strawberry cultivation is using the technique (15% of strawberry growing area). Control results have been excellent throughout the field studies, which started in 2006. For example, field results in summer 2012 in Italy showed – despite extremely difficult weather conditions – significant reduction over untreated control (mean 39% mould) by biocontrol alone (13%), and by the combined treatment (11%), while chemical control (26%) did not differ significantly from the untreated control. In the UK trial entomovectoring by bumble bees resulted in control of the grey mould, which was as good as by the chemical control. In Estonia, field studies at very low pathogen pressure nevertheless showed significantly less grey mould, and higher marketable berry yields in plots entomovectored either by honey bees, or by bumble bees (separate field studies). In 2013 similar results were obtained also from Slovenia and from Turkey. So far, all field tests using entomovectoring and Gliocladium catenulatum (Prestop Mix) on strawberries have shown excellent control results, under all weather conditions and over a wide geographical spread (from Finland to Turkey). Entomovectoring has been additionally explored, usually with excellent results, also on other crops (e.g., pear, apple, cherry, blueberry, grapewine, sunflower, alfalfa, rapeseed, etc) and against several different plant diseases and insect pests. The concept is spreading, and extensive trials are conducted not only in Europe, but also recently in Australia, South-Africa, North America, and South America. Usually honey bee colonies are employed for entomovectoring, but also commercially available bumble bees, and occasionally solitary bees, depending on the target crop.