VegNET New South Wales Regional Update

Cucurbit production plays an important role in Australia’s horticultural industry, but growers face a range of complex challenges that threaten the long-term sustainability of the sector.

One of the key challenges is pollination, a critical aspect of vegetable cultivation, which typically relies on insects to ensure effective fruit development, high yields and fruit quality. Cucurbits are monoecious plants, producing distinct male and female flowers on the same plant, which makes them particularly reliant on insect visitation for cross pollination.

Research aims to identify alternate pollinators

Since cucurbits are an introduced crop in Australia, they do not have native specialist pollinators, such as the North American squash bees. Instead, they rely primarily on European honeybees (Apis mellifera).

While European honeybees are widely used for pollination, this over-reliance on a single managed pollinator presents a significant risk, particularly with the challenges posed by disruptions in access to honeybee colonies. The incursion of the varroa mite (Varroa destructor) has had a significant impact on honeybee populations in NSW, disrupting both managed and feral colonies. This disruption underscores the need for more diverse pollination strategies to safeguard cucurbit production and ensure crop success.

Research has shown that a diversity of complementary pollinator species – including bees, flies and other insects – can improve pollination outcomes in a range of crops; however, there is limited information on the role of these species in Australian crop production, particularly for cucurbits.

In response to this challenge, UNE’s research aims to identify native insects that visit cucurbit crops and explore their potential as supplementary pollinators. This is a crucial step in ensuring the sustainability and continued success of cucurbit production amid environmental challenges.

Surveys and findings of summer observations

Through close collaboration with industry stakeholders, the UNE team and research partner SeedPurity conducted extensive surveys across 10 farms in the Hunter and Hawkesbury production regions of NSW, and caged pollination efficiency trials using managed flies in Maitland, NSW.

Pollinator survey preliminary results indicate that solitary native bees, ants and other insects visit cucurbit flowers. Further research is needed to explore ways of enhancing their populations. These surveys aim to identify key insect species to promote and develop targeted management strategies for enhancing pollination in cucurbit cropping systems.

“In the pursuit of alternative managed pollinators for cucurbits, we assessed the pollination potential of the drone fly, Eristalis tenax, for pumpkin and zucchini,” says Dr Lena Schmidt.

“Over two summer seasons in the Maitland area of NSW, cage trials indicated that E. tenax infrequently visited pumpkin and zucchini flowers and fruit set was low, hence other alternative insects are being assessed.”

FOR FURTHER INFORMATION
Please contact Dr Lena Schmidt lschmidt@une.edu.au, Romina Rader rrader@une.edu.au and Cameron Spurr cspurr@seedpurity.com, and Sylvia Jelinek on 0427 086 724 or sylvia.jelinek@lls.nsw.gov.au.

VegNET NSW would like to acknowledge Dr Lena Schmidt for contributing to this article.