Cucurbit pollination

This section presents the findings from our research study on pollination in field courgettes. Find out what we learned about the importance of pollination, what the most effective pollinators are and how to attract them.

In AHDB project CP 118, we investigated which native UK species are the most effective pollinators for field-grown courgettes. We also explored whether wildflowers had any impact on increasing pollinator numbers and courgette pollination levels.

We ran three tests on field-grown courgette crops: hand (maximal) pollination, open (natural) pollination and no pollination (pollinator exclusion) at all in field.

Our results showed no significant difference between full (hand) pollination and open (natural) pollination. But full (hand) pollination increased courgette yield by 39% when compared with no pollination at all. Pollination also increased the size and weight of the courgettes.

The findings showed that pollination is important for UK courgette crops and how effective native species are at pollinating them. Interestingly, 56% of the fruit was able to reach marketable size and shape without any pollination. This is due to a process known as parthenocarpy – fruit set in the absence of pollination.

Average fruit set of field-grown courgettes subjected to three different pollination treatments (hand pollination, open pollination and no pollination)

Our research showed that two main insect pollinators were responsible for the most pollen transfer. We carried out a further test to see whether supplementing the pollinator population would increase yields.

Pollinators rely on flowers for food. We examined how bees behaved on three different sites to see whether wildflowers can attract larger bee populations, and therefore increase pollination.

Read about the importance of courgette flowers for attracting bees and encouraging pollination. Learn how adding extra floral resources can support bee populations and boost pollination rates.