The ICAR-Indian Institute of Horticultural Research (ICAR-IIHR), Bengaluru has developed a protocol for using two native bee species, the Indian honeybee (Apis cerana) and the stingless bee (Tetragonula iridipennis), to pollinate cucurbit vegetables like muskmelon, ridge gourd, and cucumber in polyhouses. This technology helps to overcome the pollination problem of cross-pollinated vegetables under polyhouse without the need for laborious and time-consuming hand pollination. In Eurpose and other temperate countries, bumblebees are used for polyhouse pollination. But these species are not present in India and a biodiversity point of view, import of exotic species is not desirable.
The technology involves placing a honeybee hive or two hives of stingless bees at the border of the polyhouse, with the main entrance facing inside the polyhouse and other exits provided for the bees to move in either direction. The hives are placed when the crops are about to flower. The native bee species forage efficiently on the flowers of the cucurbit vegetables, visiting both male and female flowers and effecting pollen transfer to the stigma, resulting in a high fruit set and yield. The fruit weight and quality parameters obtained through bee pollination were found to be at par with those resulting from hand pollination.
Using these two native species, the ICAR-IIHR has successfully demonstrated growing muskmelon, cucumber, and ridge gourd under polyhouse without hand pollination, resulting in superior yields and fruit quality compared to open field cultivation. For instance, the yield of muskmelon (Arka Siri) was 50 tonnes per hectare (92% fruit-set), and the estimated yield of cucumber was 80 t/ha, which is 2.5 times more than open field cultivation. The technology also provides avenues for existing beekeepers to rent out beehives for pollination purposes and for farmers to save on labour costs while getting returns through honey from the hives. The initial cost of investment in this technology is about Rs. 24,000/- for six hives of stingless bees per acre, the returns are approximately eight times the cost incurred for honey bees. Additionally, it is an environmentally friendly approach he that avoids importing exotic species and promotes biodiversity conservation.
Video on honeybee pollination in a polyhouse: https://youtu.be/ne0hGmuQ43M
Source: Dr. P. Venkata Rami Reddy, Principal Scientist, ICAR-IIHR