Bombus terrestris: The Outstanding Pollinator

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Bombus terrestris for Natural Pollination

The BioBee company at Kibbutz Sde Eliyahu mass produces the earth bumblebee, Bombus terrestris, for natural pollination of various crops. Greenhouse tomato is the major crop, and added to this are sweet pepper, eggplant, strawberry, melon and courgette. Outdoor fruit crops such as cherry, plum, blueberry and avocado are also successfully pollinated by bumblebees.

Bumbus Terrestris

Why bumblebee and not honeybee?

The bumblebee, a large insect (2-4 cm in length), covered with black hair, with two wide yellow horizontal stripes and a white abdomen tip, has three distinctive advantages which make it superior to other pollinators including the honeybee:
1) Unlike the honeybee, the bumblebee is capable of vibrating the flower using the unique “buzz pollination” mechanism at which it specializes. The greenhouse tomato flower needs this vibration and is thus pollinated in the optimal way by the bumblebee. The vibration mechanism by the bumblebee is superior to any other manual alternative, such as: “electric bee”, pulsed air and hormones. In other words, nature pollinates better than any artificial means.
2) The bumblebee is less affected by adverse weather conditions as compared to the honeybee. Thus under conditions of rain, increased cloudiness or at temperatures below 10ºC, the honeybee stays inside the hive, whereas the activity of the bumblebee is not affected.
3) Unlike the honeybee, the bumblebee is better adapted to perform under confined greenhouse conditions. The bumblebee is less inclined to look for alternative sources of pollen and nectar outside the greenhouse. Therefore, it will stay in the greenhouse even if the latter is opened for ventilation purposes.

The bumblebee is an ideal pollinator for greenhouse conditions, and for outdoor crops during marginal seasons!
Pollination Services

Pollination services in the greenhouse are provided by bumblebee hives. When it leaves the factory, the standard hive contains a single queen and a few dozen workers, larvae and eggs. In a tomato greenhouse, the hive effectively pollinates an area of 2000-2500 m2 for 5 – 10
weeks. The first hive in the greenhouse establishes the “base population”, and later on additional hives are introduced to add new ones and/or replace old hives.

What does Bumblebee Activity Look Like on the Flower?

In greenhouse tomatoes it is easy to see the results of the bumblebee visit on the flower within a few hours. On the flower’s cone there appears a rust-brown spot. This sign is visible to the eye and leaves no doubt regarding the excellent quality of tomato that this flower will yield. In the pepper flower, the absence of pollen from the stamen is a distinctive sign of visitation by the bumblebee. In strawberry, eggplant, courgette and other crops there is no distinctive visitation mark on the flower and the result is therefore observed in the newly-set fruit.

Sugarwater

Sugarwater solution is supplied to the hive as a substitute for nectar which is missing from the tomato flower, or as a supplement to the existing, but insufficient nectar in the flowers of sweet pepper and strawberry. The sugarwater unit, located at the bottom of the hive, supplies sugarwater continuously throughout the entire period of time that the hive stays in the greenhouse. This system is maintenance-free, and requires no special care or replacement.

Placement of the Hive in the Greenhouse

Upon receiving the hive, the following steps should be taken:
1) Place the hive in a prominent location in the greenhouse, sufficiently ventilated (both in winter and summer) and shaded (during the hot season). It is important that under any condition, the hive is not exposed to direct sunlight.
2) The hive is placed on a supporting stand which was developed specifically for this purpose. In the lower third of the base, smear a line of insect-trapping glue in order to prevent access of ants to the hive.
3) Check that the area in the immediate vicinity of the hive remains clear of any vegetation. To ensure this during the entire growing season, trellis the plants adjacent to the hive. If possible, allow the foliage to shade the hive.
4) After placing the hive, let the colony inside “settle down”. After a few minutes, carefully open the flight-hole by lifting the shutter which blocks it. The bees will leave the hive immediately and begin their “orientation flight” which will later enable them to find their way back to the hive without difficulty. If the hive is placed at dusk, open it the following morning.
5) In any case, do not change the original position of the hive without first consulting your field advisor.
6) During the first three days, until the hive is fully active, back up the pollination using either an “electric bee”, pulsed air, or hormones. Manual pollination should be ceased only after the hive is fully functional and upon consultation with your field advisor.
7) Regarding specific instructions before every season, please consult your field advisor and read any other information which may be distributed for this purpose.
Bumblebees and Pesticides

Natural enemies for biological pest control do not harm the bumblebees whatsoever. Therefore, they can be combined with the bumblebees without limitation.

As a rule, all pesticides that are forbidden for use in the presence of honeybees, are not recommended for use in combination with bumblebees.

In case of using chemical pesticides in the greenhouse, it is important to follow these rules:

1) Do not place the hive adjacent to where pesticides are stored.
2) The use of chemical pesticides prior to introduction of the bumblebees requires consultation with our technical advisory service regarding the suitable timing of placement of the hive.
3) During the first week following placement of the hive, avoid any chemical pesticides.
4) In any case, try to avoid non-selective pesticides or those with a long residual effect. Only under special circumstances is it possible to use compounds with a short residual effect. Then it is necessary to remove the hive from the greenhouse using the “BeeHome” system and return it after a certain period of time (see specific instructions).
5) Dustable compounds (e.g. sulphur) might especially harm the bumblebees because during their flight, they adsorb the pesticide and bring it back to the hive where it is transferred, one way or another, to the brood.
6) When working with a fogger, remove the hives during spraying, even when using permissible pesticides.
7) Even if a certain pesticide apparently does not affect the bumblebees, its frequent application might cause cumulative damage.
8) Any combined use of compounds requires consultation with our field advisory service since often it has a cumulative or even a synergistic effect on the bumblebees.
9) Remember that even a drift of a harmful and residual pesticide which is sprayed in a neighbouring plot could be detrimental to the bumblebees.
10) Make sure to remove the sprayer and any empty pesticide containers from the area of the greenhouse.

Removal and Return of the Hive Following Pesticide Application

1) Return the bees to the hive using the BeeHome system.
2) Remove the hive from the greenhouse and store it at a temperature of 20 – 28ºC. Avoid storing it in the vicinity of pesticides.
3) At the end of the suitable time period following pesticide application, transfer the hive back to its original location in the greenhouse. The flight-hole may be opened after approximately half an hour.

Try to prevent moving and transferring the hive as much as possible. This kind of action has a cumulative deleterious effect on the bees’ activity.
In Case You are Stung…

Bumblebees are usually very docile and sting infrequently. In any case it is best to avoid blue or dark purple clothing, aftershave and various cosmetics, which are known to attract the bees. It is also recommended that whoever is not needed to work in the greenhouse (e.g. children) should not walk around there unnecessarily.

In general, the sting of the bumblebee causes local irritation accompanied by a slight swelling around the point of the sting. Apply ice to ease the reaction which should disappear within a short time (minutes to a few hours). However, as rare as it may be, there are individuals who may develop a hypersensitive reaction to the bumblebee sting, manifested as generalized itching, not necessarily at the site of the sting, irritation of the mucous membranes of the eyes and nose, sneezing and shortness of breath. In this event, seek immediate medical care.