Both in open ground and greenhouses pollination with bumblebees (Bombus terrestris) is gaining popularity. Bumblebees have a range of advantages over bees. Thus in some cases it is more efficient solution to choose bumblebees pollination.
Advantages of bumblebees as pollinators:
Tomato and some other crops do not accumulate nectar, therefore bees do not pollinate them. For natural pollination of such crops in industrial greenhouses you cannot go without bumblebees. It should be noted that due to effective pollination, bumblebees are able to increase the yield of tomatoes by 25-30%. In film greenhouses, bumblebees can be more effective than bees and on cucumber, as they continue to pollinate even in conditions of insufficient illumination and sharper temperature changes.
Pollen becomes sterile at temperature of 10 °C. Elevated temperature also does not have the best effect on pollination of tomatoes. Pollen of cucumber and tomato loses viability at temperatures above 30 °C. Sterile pollen will not lead to the fruit setting, regardless of the method of pollination.
Air humidity above 70% leads to sticking of pollen and sets are not formed. At too low humidity (40%), pollination also does not occur, as the pollen dries.
Pollinated tomato flowers have external differences: the petals are directed back, and on the flower itself you can see the traces of the bumblebee jaw - darkened points or stripes. The flower remains open for 1-3 days and must be pollinated before closing. The effectiveness of pollination by bumblebees is checked every two days, checking open and already closed flowers. On open flowers, which are more than one day, there must be one to five bites. If the number of bites is reduced to 1-2, then it is necessary to put another hive in the greenhouse. All closed flowers should be bitten.
There is a problem of disorientation of insects-pollinators when they are applied in greenhouses with supplementary lighting and in film greenhouses. This is due to the fact that bumblebees use a blue spectrum of light to orient themselves, and when illuminated it lacks. In film greenhouses, the light of the blue spectrum also does not pass enough. In order bumblebees could get well from the hive to the plants and back, you can install additional blue LED strips or hang blue glue traps. It is important that the blue traps or LED strips would not be located in another place with time.