UC Agriculture and Natural Resources released information on Mar. 10 about the causes of poor pollination in raspberries, highlighting the importance of bee activity for healthy fruit development.
The topic is significant for growers who rely on effective pollination to ensure quality raspberry crops. Poor pollination can lead to misshapen or crumbly fruit, which affects both yield and marketability.
According to the post, while weather, genetics, or viruses can cause problems with raspberry formation, a lack of pollinators such as domestic and wild bees during flowering is most often responsible. The article states that although raspberry flowers are self-pollinating, bee activity accounts for 90-95% of successful pollination. It recommends two strong hives per acre for optimal results. The structure of the raspberry flower requires pollen transfer to each pistil to form mature seeds and druplets; if some druplets are not pollinated, the fruit becomes compromised and may fall apart easily.
The post also advises growers to ensure hive strength by checking for many frames of brood in spring and observing heavy flight activity in fields. It notes that honeybees may be attracted away from raspberries if other flowers are more appealing or if overwatering makes nectar less attractive. Additionally, some pesticides might repel bees even if they are not directly toxic.
UC Agriculture and Natural Resources enhances lives statewide by sharing science-based practices according to its official website. The organization maintains nine Research and Extension Centers as living laboratories across diverse ecosystems according to its official website and operates offices in all 58 California counties according to its official website. Glenda Humiston serves as vice president according to the official website. UC Agriculture and Natural Resources applies University of California expertise through research and outreach initiatives according to its official website, delivering knowledge that supports well-being, economic opportunities, farming practices, environmental conservation, wildfire protection, nutrition programs, food networks, and youth education across California according to its official website.
The article concludes by thanking Dr. Eric Mussen from UC Davis for his contributions on this issue.