Home ​​​​>​​​​ Knowledge Center​​​​

The zucchini has both male and female flowers on the same plant. Both flowers produce nectar. In addition, the male flower also produces pollen. Each zucchini flower only blooms for one day. The flower is only open in the morning for a short period of time and can be closed already after 10 am. During this time pollination must take place. You can check the whim of the bumblebees by looking at:

• the presence of pollen grains on the stigma in the female flower
• whether the stamens in the male flower have been partially or completely stripped of pollen grains.

During dark and rainy periods, sometimes not enough bumblebees fly out and pollination does not go well. Do you fear that pollination is not going well? Then pollinate by hand.

For the best effect of using bumblebees in zucchini cultivation, the following aspects are important:

1. Upon receipt, check the product for discrepancies and report any complaints or comments within 24 hours. Place the bumblebee hives in the desired location within one hour after receipt and open the flight opening after +/- one hour. Open the bumblebee hive until 2 hours before sunset at the latest.
2. Place the bumblebee hive horizontally, also during transport. Avoid insects such as ants by placing the bumblebee hive at least one meter above the ground. These can disturb the development of the bumblebees. When the bumblebee hive is held at an angle or placed at an angle, sugar water can spill out.
3. Store the bumblebee colonies under the right conditions. If storage is required, store the bumblebee hive at a temperature of 18-20°C for up to 24 hours in a ventilated area. 
4. Provide enough bumblebees by deploying five to eight bumblebee colonies per hectare on a weekly basis. 
5. Place the bumblebees in a dry spot in the shade. If the bumblebee hive is in the sun, the inside temperature of the hive can rise up to fifteen degrees. High temperatures cause a less good whim, because more bumblebees will stay in the nest to provide cooling. Therefore, try to create shade by attaching a wooden plate on top of the bumblebees.
6. Alternate the flight openings with multiple bumblebee hives. When placing multiple bumblebees on top of each other, it is important to have the flight openings point in the opposite direction. This to avoid confusion for the workers. For example, if the opening of hive one points to the East, hive two points to the West and hive three points to the East again. 
7. Close the sugar wick with a cap. Agrobio bumblebee colonies contain a reservoir with sugar water under the cage of bumblebees. This serves as food during storage, transport and application in, for example, tomato cultivation. Unlike tomato flowers, zucchini flowers contain nectar. This means that the sugar water in the bumblebees during application in a zucchini cultivation is superfluous. In order to prevent bumblebees from using sugar water instead of nectar, it is wise to close the sugar wick with a cap before application. This ensures that bumblebees are more stimulated to collect nectar and thus visit the flowers. 
8. Always check the effect of a chemical correction on bumblebees. If you want to apply a chemical correction, check beforehand what effect it has on bumblebee colonies. Always consult the Royal Brinkman spray advice cards for this. When the chemical correction affects bumblebees, the bumblebee colonies should be removed from the greenhouse. It is important that they are placed in a place where the conditions are approximately the same as in the greenhouse (18°C to 20°C). In preparation for moving the bumblebees, it is necessary to convert the flight opening to the one-way position (fly-only position) a few hours in advance. 
9. Be careful with air heating systems in the greenhouse.
   The CO2 that comes from the air heating installation is used by the plants during the growing process. Bumblebees can be sensitive to this. Therefore make sure that you do not place the bumblebees under these systems where the CO¬2 levels are highest (more than 2500 ppm). 
10. Prevent bumblebees from looking for pollen outside the greenhouse.
    As mentioned earlier, the flowers of the zucchini are open to a limited extent in the morning. This can prevent bumblebees from being tempted to look for pollen elsewhere outside the greenhouse. However, there is a good chance that the bumblebee will not find its way back in that case. To prevent this, you can put the bumblebee hive on the fly-only position just after noon. Bumblebees that return to the hive will not be able to fly out during the rest of the day. In that case, make sure that the bumblebees are opened again before the next morning, so that they can fly out when the flowers are open.

Note: zucchini colonies are not available. Order them on time!

Can't find your answer? Fill out the contact form and our specialist Kevin van Kester will get back to you. On weekdays, even within 24 hours.