Varroa destructor is a parasitic mite, which is considered a severe pest for honey bees causing serious losses to beekeeping. Residual hydrolats from steam extraction of hop essential oils, generally considered as a waste product, were tested for their potential use as acaricides on V. destructor. Four hop varieties, namely Cascade, Spalt, Victoria, and Mapuche, showed an interesting performance as feasible products to be used in the beekeeping industry. Some volatile oxidized terpenoids were found in the hydrolats, mainly β-caryophyllene oxide, β-linalool, and isogeraniol. These compounds, together with the presence of polyphenols, flavonoids, and saponins, were probably responsible for the promissory LC₅₀ values obtained for mites after hydrolat exposition. Victoria hydrolat was the most toxic for mites (LC₅₀: 16.1 µL/mL), followed by Mapuche (LC₅₀ value equal to 30.1 µL/mL), Spalt (LC₅₀ value equal to 114.3 µL/mL), and finally Cascade (LC₅₀: 117.9 µL/mL). Likewise, Spalt had the highest larval survival, followed by Victoria and Mapuche. Cascade was the variety with the highest larval mortality. In addition, none of the extracts showed mortality higher than 20% in adult bees. The Victoria hydrolat presented the best results, which makes it a good compound with the prospect of an acaricide treatment against V. destructor.

In the late winter or early spring, beekeepers stimulate the colonies to increase the population of bees using different dietary supplements, principally based on carbohydrates and proteins. Honey bees require multiple sources of nectar and pollen to obtain balanced nutrition, so the formulation of effective supplements requires the identification and testing of candidate components, especially at the colony level. In this study, we evaluated the effectiveness of a nutritional supplement (SUP) composed of two important phytochemicals that have been reported to improve honey bee health (abscisic acid (ABA) and p-coumaric acid (CUM)) combined with fish protein hydrolyzate (FPH), and essential omega fatty acids (Ω3/6) in nuclei colonies. We first evaluated the toxicity of SUP compared with the control (sugar syrup) in laboratory bioassays during 96 hours. Then, we tested the effect on the amount of brood, honey, and pollen in bee hives nuclei supplemented with SUP for thirty days. In addition, we quantified and compared the concentration of total proteins in individual honey bees collected at the beginning and at the end of the experiment. The results obtained show that SUP is palatable, nontoxic to Apis mellifera, and significantly increases the amount of open brood and pollen reserves of bee nuclei compared with nuclei feed with sugar syrup. No significant differences were observed, between nuclei feed with SUP and control nuclei, in the amount of honey reserves and total proteins of individual bees. Here, we show the value of a nutritional supplement that combines essential nutritional components and phytochemicals to improve important parameters associated with colony fitness. We expected this nutritional supplement helps beekeepers to develop their colonies in view of the increase of industrial agriculture and the consequent loss of floral resources.

Kiwifruit (Actinidia deliciosa) is a globally important crop presenting challenges for ensuring cross-pollination. This study aimed to (1) record the entomological fauna visiting flowers; (2) evaluate the visitation frequency of pollinators; and (3) test the use of lavender extract to enhance cross-pollination by honeybees and assess the impacts on fruit quality. Nine species of floral visitors were recorded as pollinators, although the most frequent were the exotic honeybee (Apis mellifera) and the native bees Bombus pauloensis and Xylocopa augusti. Honeybees increased their visitation to flowers when the attractant was used, improving pollination service and fruit quality compared to the control-bagged treatment, resulting in fruits that were 20 g heavier (115.4 g vs. 95.6 g, 95% CI). Similarly, the number of seeds per fruit and the fruit shape index (FSI) increased in treatments exposed to bee visitation when compared to the bagged control. However, differences in bee visitation among treatments suggested a non-linear relationship between bee activity and fruit quality. Nevertheless, achieving high-quality fruit standards across treatments could be explained by the extended floral lifespan, which allowed for a high number of visits and ensured pollination. Finally, we did not observe any bias in honeybee visitation by applying sugar syrup combined with the attractant. Hence, to increase honeybees’ visits to flowers, we recommend applying the scent directly in a water solution.