Cucurbit pollination: the most effective pollinators

Our study showed that honeybees and buff-tailed bumblebees are the most effective pollinators of courgettes. Whether adding managed colonies of bees would increase courgette yields was also tested.

Most horticultural crops need high levels of pollination to produce reliable yields. Making your land more attractive to bees will ensure you get the pollination levels you need over time.

Our tests showed that honeybees (Apis mellifera) and buff-tailed bumblebees (Bombus terrestris) were the most effective pollinators of courgettes. Buff-tailed bumblebees carried more loose pollen grains than honeybees – that means they have a higher pollination potential. Buff-tailed bumblebees also had an equal preference for visiting both male and female courgette flowers, which is ideal for transferring pollen.

We tested whether introducing managed bee colonies can increase courgette yields.

We stocked one courgette field (2.58 ha) in Cornwall with six commercially reared colonies of buff-tailed bumblebees. We compared the yield when colonies were open and when colonies were closed. The results showed no significant difference, likely due to the activity of lots of natural pollinators at that site.

In conclusion, growers should concentrate on making their land attractive to existing wild bee populations rather than supplementing with managed colonies.