Concerns about declining bee populations and the environmental impact of food production often lead to questions about bee health in avocado farming. This article clarifies the connection between bees and avocado cultivation, detailing pollination practices and factors affecting bee well-being.
The Unique World of Avocado Pollination
Avocado trees display “synchronous dichogamy,” a unique flowering behavior where individual flowers open twice over two days. Each flower first functions as female, receptive to pollen, then closes before reopening as male to shed pollen. This promotes cross-pollination, as male and female phases rarely overlap, making self-fertilization unlikely.
For successful fruit development, pollen must reach a receptive female flower, often on another tree. Avocado cultivars are “A” or “B” types, differing in their daily opening patterns. “A” types are female in the morning and male on the second afternoon, while “B” types are female in the afternoon and male the next morning. Planting both types in an orchard facilitates cross-pollination and improves fruit yield.
Honeybees are the primary commercial pollinators in avocado orchards due to their efficiency and numbers. They transfer the 20+ pollen grains needed for a single avocado fruit to develop. While honeybees are widely used, other insects like native bees, stingless bees, bumblebees, hoverflies, wasps, and beetles also visit avocado flowers and contribute to pollination.
Addressing Bee Mortality Concerns in Avocado Cultivation
Bees do not directly “die for avocados.” However, some avocado cultivation practices affect bee health. Pesticide use is a factor, as chemicals in groves can be toxic. Certain pesticides, like neonicotinoids and fipronil, have been linked to mass bee deaths in areas of expanded avocado cultivation, such as Colombia.
The migratory nature of commercial pollination services stresses bee colonies. Honeybees are frequently transported vast distances from overwintering sites to various agricultural areas, including almond and avocado groves. This movement can weaken colonies and expose them to diseases and other stressors.
Bees can also face nutritional stress in large monocultures lacking diverse foraging options. While avocado flowers offer nectar and pollen, limited floral variety can cause deficiencies, weakening bee immune systems. Honeybees may sometimes prefer other floral sources, requiring strategic hive placement and management for effective avocado pollination.
Wider Threats to Bee Health
Bee health is a complex issue with multiple influencing factors beyond any single crop. Habitat loss and fragmentation impact bee populations by reducing natural foraging and nesting sites. Converting natural landscapes into agricultural or urban areas diminishes the diverse plants bees need for nutrition.
Climate change also poses a threat, altering plant flowering times and distribution. This can mismatch bee emergence with food availability. Rising temperatures and extreme weather events can harm bee populations and disrupt their relationship with blooming plants.
Diseases and pests, like Varroa mites (Varroa destructor) and American foulbrood, contribute to bee decline. Varroa mites weaken bees and transmit viruses, while bacterial and fungal diseases can destroy colonies. Pesticide exposure, including insecticides, fungicides, and herbicides, impairs bee navigation, immunity, and reproduction.
Colony Collapse Disorder (CCD) is the sudden disappearance of adult bees from a hive. No single cause is definitive, but CCD is believed to result from combined stressors: pesticides, pathogens, parasites, malnutrition, and environmental factors.
Promoting Bee Health in Avocado Orchards
To mitigate impacts on bees, sustainable practices are adopted in avocado cultivation. Integrated Pest Management (IPM) strategies reduce reliance on harmful pesticides. IPM involves monitoring pests, using targeted less toxic alternatives, or applying pesticides only when necessary and during minimal bee activity.
Bee-friendly practices include timing pesticide applications to avoid foraging periods and selecting lower-toxicity chemicals. Providing diverse forage within or near orchards, like cover crops or wildflowers, offers bees varied nutritional sources, improving their health and resilience.
Collaboration between avocado farmers and beekeepers ensures managed colony health. This involves discussing pesticide use, optimizing hive placement, and ensuring adequate bee nutrition throughout pollination. Research and development breed more resilient bee strains and explore alternative pollination methods, supporting the sustainability of both avocado production and bee populations.