Using bumblebees has been shown to significantly boost melon size, sweetness and market value of the crop.
Reliable pollination for brief flowering period in melons
Timing is everything when pollinating melon crops to maximise returns for growers. With separate male and female flowers on the same plant, each melon flower opens once for a short period early in the day. Prompt efficient pollen transfer is essential to optimise fruit set.
“Pollen release levels peak early in the day, when the female flowers are most receptive,” explain Ella Tuyttens, pollination researcher at Biobest. “If the flowers are not pollinated the day they open, there is no second chance.
“Traditionally, melon growers rely on honeybees and natural pollinators. With a very narrow pollination window, unsettled weather can prove costly. Honeybees are more sensitive and unwilling to fly in cool, windy or wet conditions.”
Why use bumblebees in melons?
“Bumblebees start foraging earlier in the day and fly better in less- than-ideal conditions,” explains Ella. “With larger, hairier bodies, they collect and deposit more pollen per flower visit. This further boosts pollination rates and efficiency.
“In tunnel or glasshouse grown crops, diffuse light can negatively impact honeybee performance. However, this has been shown to have little impact on bumblebee flying behaviour and hence pollination efficiency. With the pollination timing constraints, it is crucial pollinators are highly reliable and efficient.”
Bumblebee pollination in melons
In 2025, a Biobest trial in Belgium assessed the potential for Biobest bumblebee hives to improve the market value of a commercial melon crop, which is largely dependent on size and sugar content (brix). The trial compared three pollination strategies in a protected crop of Charentais melons; only honeybee hives, only bumblebee hives, and honeybee plus bumblebee hives.
The results showed when Biobest bumblebees were included the crop produced higher percentages of heavier and sweeter fruits. Producing statistically more Class 1 fruits, in the 800-1200g weight range, led to a 40%* revenue increase. Better pollination leads to more seeds, which in turn stimulate the production of growth hormones, resulting in larger, sweeter melons with fewer deformities.
Graphs show increased weight and brix value when bumblebees are used.
“The highest sugar content was recorded in the crop pollinated with both honeybees and bumblebees,” says Ella. “From our research we conclude the combination of bumblebees and honeybees is best for overall melon quality, yield and market value.”[LV1.1][Jv1.2]
*This figure can vary between different markets.