Currently over 99,000 acres of tomatoes are grown worldwide within greenhouse enclosures and pollinated by bumble bees. In the US, approximately 37% of tomatoes sold in grocery stores are grown in greenhouses and this percentage is continuing to rise. Commercially produced colonies of Bombus impatiens are almost exclusively used in the US as the sole pollinator of greenhouse tomatoes. Colonies typically last 8 to 12 weeks in the greenhouse before pollination levels drop and colonies are replaced. Currently, growers visually examine flowers for scarring caused by the bumble bees to assess pollination activity. However, this technique is both inaccurate and labor intensive. The accuracy of this information is critical in determining the colony placement within the greenhouse and when to replace colonies. The objective is to develop a more effective tool to monitor pollination activity of greenhouse tomatoes. Sentinel plants were equipped with detectors sensitive to vibrations being telegraphed through the plant stem by bumble bees as they forage for pollen. This behavior, termed 'buzz pollination' is then quantified to monitor bumble bee visits and pollination activity. This signal, then, is recorded and transformed into a visual wave form which can be easily and accurately quantified. This technique, adopted by a grower, could assist in the maintenance of optimal pollinator / plant interaction. This tool will increase both accuracy and efficiency of monitoring pollination activity by bumble bees.