Effect of bumble bee (Hymenoptera : Apidae) pollination intensity on the quality of greenhouse tomatoes

Laboratory studies were conducted to assess tomato, Lycopersicon esculentum Mill. (Solanaceae), quality in relation to the level of buzz-pollination b y bumble bees. Studies were conducted in commercial tomato greenhouses in t he Leamington. Ontario, area to categorize bruising of tomato anther cones by bumble bees into five levels of bruising. The number of pollen grains pe r stigma was determined for each bruising level, and the bruising level was found to be a good predictor of stigmatic pollen lend. Experimental flower s were pollinated by bumble bee and assigned to bruising levels based on th e degree of anther cone discoloration. Fruit set, tomato weight, minimum di ameter, the number of days until ripe roundness, weigh, percentage sugars, and number of seeds were assessed and compared among bruising level. Fruit set in flowers receiving no pollination visits was 30.2%, whereas, 83.3, 84 .4, 81.2, and 100% of the flowers set fruit in bruising levels 1, 2, 3, and 4, respectively, minimum diameter, number of seeds, and tomato weight all increased from no bruising to different levels of bruising. There was no in crease in weight or. diameter above a bruising level of 1, and no increase in the number of seeds per fruit after a bruising level of 2. We found that pollination of tomato flowers greater than a bruising level of 2 (correspo nding to approximately one to two bee visits) did not result in a significa nt increase in quality.