The guayule, an unexpected ally against the attack of the fungus that threatens 85% of Spanish beehives

A new study has revealed that the guayule plant, native to North American deserts and cultivated in parts of Spain’s Castilla-La Mancha region, could offer a sustainable solution to combat Nosema ceranae, a fungal parasite threatening up to 85% of bee colonies in Spain. The research, conducted by the IRIAF (Institute for Regional Research and Development in Agriculture, Food and Forestry of Castilla-La Mancha), suggests that extracts from the guayule may have properties capable of targeting this harmful fungus. The discovery comes after years of investigation into the mysterious decline of bee populations. Nosema ceranae was first identified in 2004 and has since become a major concern for beekeepers across Europe. It affects the digestive system of honeybees, leading to colony collapse and massive losses. In Castilla-La Mancha, the disease has been linked to the disappearance of entire colonies, with researchers estimating its presence in nearly all apiaries in the region. Mariano Higes, a leading researcher at IRIAF, has played a key role in studying the impact of Nosema ceranae. He explains that the fungus spreads through contaminated food sources such as pollen and honey, and can persist in the environment due to its resilient spores. These spores can survive in the hive, spreading among bees through direct contact or via the fecal-oral route. Once infected, bees experience weakened immune systems, reduced productivity, and ultimately death. Higes notes that the lack of effective treatments has left beekeepers with limited options. Currently, there are no registered medications available in Europe to treat nosemosis type C, the condition caused by Nosema ceranae. This absence of therapeutic interventions has forced researchers to seek alternative solutions, including exploring natural compounds with antifungal properties. It was the IRIAF team who first detected the presence of Nosema ceranae in honeybee colonies over two decades ago. At the time, they observed unusual patterns of colony loss that did not align with known causes. Their findings led to the identification of a new form of nosemosis, which has since become a focal point for scientific inquiry. Over the years, the institute has developed expertise in understanding how the parasite interacts with bee biology and spreads within hives. The collaboration between IRIAF and the University of Castilla-La Mancha (UCLM) marks a significant step forward in addressing the crisis. Researchers at UCLM noted that certain substances secreted by the guayule plant might possess pharmacological properties, particularly against fungal infections. Given that Nosema ceranae is itself a fungus, these potential benefits make the plant a promising candidate for further exploration. The implications of this research extend beyond the immediate challenge of protecting bee populations. With bees playing a crucial role in pollination and ecosystem health, their decline poses risks to agricultural productivity and biodiversity. The search for sustainable alternatives to synthetic pesticides and fungicides has gained urgency as environmental concerns grow. The study highlights the need for more comprehensive monitoring of bee health and the implementation of preventive measures to curb the spread of Nosema ceranae. As the research progresses, scientists hope to determine whether extracts from the guayule can effectively reduce infection rates and support the recovery of affected colonies. The results of these preliminary studies will likely shape future strategies for managing the disease and preserving beekeeping practices in Spain.