The potential of wildflower strips to enhance pollination services in sweet cherry orchards grown under polytunnels

Abstract

1. Sweet cherry production benefits from insect pollination, but the extent to which wildflower strips can boost pollinator visitation under polytunnels is unknown. 2. Wildflowers were established in alleyways between tree rows under polytunnels in 10 commercial cherry orchards. Their management involved either a single cut in September (Standard Wildflower Strips (SWS)) or being actively maintained to 20 cm with regular cutting (Actively Managed Wildflower Strips (AMWS)), compared with unsown Control Strips (CS). Flower visitors of cherry and wildflowers were recorded by visual observations for 3 years (2017-2019), while cherry production (quantity and quality) was assessed in 2019.3. In total, 67 visitor species were identified; managed commercial species (Apis mellifera and Bombus terrestris) made up ~74% of all records. During the cherry blossom period (anthesis), AMWS had the highest visitor density to cherry blossoms compared with CS and SWS but no significant difference in harvestable fruit was recorded. After anthesis, greater visitor density, diversity and richness were observed in both wildflower treatments compared with CS, being greatest in SWS, which was consistent with differences in floral communities between treatments. 4. Although visitor density was not correlated with fruit set, pollinating insects were key for fruit yields and quality. Fruit set was ~17% from blossoms exposed to visitors compared with <1% when excluded. Furthermore, hand pollination resulted in ~32% fruit set, indicating greatest pollination deficits in CS (~50%) compared with AMWS (~28%) and SWS (~35%). Synthesis and applications.Sweet cherry is highly dependent on pollinators to underpin commercial yields, and pollination deficits exist under polytunnels.

Fishing for flies: testing the efficacy of “stink stations” for promoting blow flies as pollinators in mango orchards

“…As such, we do not know how the abundance of flies changed with increasing distance from the stink stations in the adjacent rows. Some orchard pollinators, like honey bees, are known to forage by moving primarily along rows of trees (Kobayashi et al 2010;Mateos-Fierro 2020) and make infrequent movements between rows. In contrast, non-bee pollinators are believed to make more frequent movements between rows.…”

“…Flies often forage at different times of day and temperatures to bees (Ssymank et al 2008), being more active in the early morning or during cold or rainy weather, as well as later in the flowering season (Ellis et al 2017). Finally, non-bee pollinators have different patterns of movement within orchards than honey bees (Singh et al unpublished), which tend to forage along linear features (Kobayashi et al 2010;Mateos-Fierro 2020). As such, flies may be more likely to move pollen over greater distances and between adjacent varieties, thereby increasing the likelihood of cross pollination, which is important in many crops (Stern et al 2004;Hudewenz et al 2014;Gaffney et al 2018).…”

Mason bees and honey bees synergistically enhance fruit set in sweet cherry orchards

“…increasing the quality and quantity of floral resources, protecting and restoring semi‐natural habitats) for native pollinators in and around crop fields should be given priority to enhance the diversity of pollinators (Osterman, Aizen, et al, 2021 ). For instance, by providing co‐flowering plants or managing orchards organically, cherry pollinator richness can be enhanced (Gilpin, O'Brien, et al, 2022 ; Mateos‐Fierro et al, 2023 ; Rosas‐Ramos et al, 2020 ). Notably, measures promoting pollinators should be tailored to geographical regions and local conditions, as pollinator communities differ between regions (Dar et al, 2018 ).…”

Location and Creation of Nest Sites for Ground-Nesting Bees in Apple Orchards

“…To maintain abundant populations of functionally important pollinators in agricultural landscapes, provision of both nesting and floral resources is required. While the establishment of additional floral resources in fruit systems has been relatively well-studied [ 17 , 20 , 21 , 22 ], the extent to which orchards and associated habitats support ground-nesting bees is not well known. To support the more sustainable production of apple crops and reduce potential pollination deficits, we need to better understand and potentially promote bees nesting in and around orchards.…”