-The primary food of adult honey bees (Apis mellifera ) is honey prepared by bees from nectar, provided by plants in order to stimulate the bee's pollination service. Nectar consists of carbohydrates, amino acids and water, as well as other minor compounds whose proportion varies among plant species and whose biological implications in the honey bee physiology require intense research. Several environmental stressors are causing the decline of bee colonies, and thereby, we tried to connect the nutritional quality of bee's diet with the strength of the bee's immune system. The phytohormone abscisic acid (ABA) is present in nectar, honey and adult honey bees. It has been demonstrated that ABA stimulates innate immune defences in animal cells. However, the influence of ABA on A. mellifera 's health and fitness is unknown. Here, we show that honey bees fed with an ABA supplement in field experiments resulted in (i) the appearance of ABA in larvae and adult bees, (ii) enhanced haemocyte response to non-self recognition, (iii) improved wound healing and granulocyte and plasmatocyte activation and (iv) maximum adult bee population after the winter and increased pesticide tolerance. The results indicate that the naturally occurring compound ABA has a positive influence in honey bee immunity. ABA emerges as a potent booster of immune defence in A. mellifera and may be useful in addressing the colony losses threatening apiculture and pollination service worldwide.Apis mellifera / abscisic acid / immune aptitude

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-An organic product based on oxalic acid was evaluated for use in Varroa control under spring/summer climatic conditions in Argentina. The formulation consists of four strips made of cellulose impregnated with a solution based on oxalid acid. Forty-eight beehives were used to assess the product efficacy. Residues of the product were also tested in honey, bees, and wax. Each trial had respective control groups without oxalic treatment. At the beginning of the experiment, four strips of the formulation were applied to the colonies belonging to the treated group. Falling mites were counted after 7, 14, 21, 28, 35, and 42 days. After the last count, the strips were removed and colonies received two flumethrin strips for 45 days. Falling mites were counted throughout this period. Average efficacy of the organic product was 93.1 % with low variability. This product is an organic treatment designed for Varroa control during brood presence and represents a good alternative to the synthetic treatments.Varroa destructor / control / oxalic acid / bee brood / Argentina