A comparative study of the efficiency of bumble bees and an electric bee in pollinating unheated greenhouse tomatoes

SummaryThe efficiency of an electric bee in pollinating tomatoes grown in an unheated greenhouse was compared with that of bumble bees. Two years of experiments show that under the moderate climatic conditions of autumn and early winter, the two methods had similar effects on fruit set, seed number, fruit size and yield. Under more severe winter conditions, however, bumble bees were more efficient than the common agricultural practice of using the electric bee 2–3 times a week. Even in the presence of relatively low amounts of pollen grains per flower, a high percentage of fruit set was obtained by the bees. Under these adverse climatic conditions, flower vibration with the electric bee and with bumble bees achieved equal degrees of fruit set, only when the electric bee was operated every day. It may be concluded, therefore, that bumble bees are efficient pollinators as long as the flower organs are functional and a minimum number of pollen grains is available. For achieving similar pollination efficacy w...