Using bumblebees as an additional or alternative pollination strategy can enhance kiwifruit yield and quality. It can also deliver an attractive return on investment (ROI).
Traditionally, kiwi growers rely on multiple techniques to pollinate their crops. Some growers hire in honeybee hives or carry out mechanical pollination, while others simply rely on natural pollinators. According to our research, bumblebees can add value for the grower in all these pollination strategies.
What are the pollination challenges in kiwis?
As a dioecious crop, kiwis require cross-pollination between male and female plants for successful fruit set. Because the crop has a high pollen demand, poor pollination directly impacts yields and fruit quality. Most kiwi varieties have a very short flowering period, typically lasting only 10-14 days. During this critical window, unsettled weather can prove costly, as most pollinators are reluctant to fly in wet, cool or windy conditions.
Why use bumblebees in kiwis?
“Bumblebees are more reliable pollinators,” says Spiros Kavouras, Global Technical Specialist at Biobest. “Compared to honeybees, bumblebees fly more frequently between the crop rows and deposit more pollen per flower due to their larger, hairier bodies. Bumblebees are also more resilient pollinators, remaining active and effective in unsettled weather conditions. These characteristics can improve pollination levels in crops with a narrow pollination window.”
Bumblebee pollination in kiwi crops
Recent trials in kiwi crops in Greece compared the performance of Biobest bumblebee Multi Hives with existing pollination techniques. Nets erected between the trial plots kept the different insect pollinators apart.
Plots pollinated by bumblebees recorded yield improvements of 7-16% compared with plots relying on honeybees or natural pollinators. Fruit size, shape and sugar content were comparable or improved. All these improvements led to an increase in revenue 6-7 times higher than the cost of the bumblebee hives.
How do bumblebees compare to mechanical pollination in kiwi crops?
Mechanical pollination in kiwi crops was developed to overcome the inefficiencies of traditional insect pollination. However, these techniques are often highly labour intensive. They also require large amounts of costly pollen.
An additional trial tested whether bumblebees could improve pollination in mechanically pollinated kiwi crops. The trial compared standard mechanical pollination with a combined approach integrating bumblebees. The plot with Biobest bumblebee Multi Hives recorded a higher yield and larger fruit size, while reducing unmarketable fruit from 14.5% to 8.0% (a 45% reduction). This resulted in a revenue increase of 12% and an ROI of 7%.
“This trial shows that Biobest bumblebee Multi Hives can also improve yield and fruit quality in kiwi crops where mechanical pollination is used,” concludes Spiros.
For more information, contact your local Biobest advisor.