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• The effects of spinosad insecticide to adults of Apis mellifera, Megachile rotundata and Nomia melanderi (Hymenoptera: Apidae)

  93-97.

  D. F. Mayer

  G. Kovács

  B. L. Brett

  B. L. Bisabri

  Views:

  252

  The toxicity of spinosad to adult female bees tended to be least to the honey bee (Apis mellifera L.) (LD₅₀ = 0.078 pg/bee), intermediate to the alkali bee (Nomia melanderi) (0.065 pg/bee), and greatest to the alfalfa leafcutter bee (Megachile rotundata (F.)) (0.058 pg/bee), both in topical drop tests and in tests involving spinosad residues on alfalfa (Medicago sativa) foliage. For the calculated LD₅₀ pg/g, the honey bee (LD₅₀ = 0.612 pg/g) was the most susceptible followed by the alkali bee (0.773 pg/g) and the leafcutter bee (1.908 pg/g). The honey bee oral LD50 was 0.063 pg/bee and the calculated LD₅₀ 0.492 pg/g. Adding an adjuvant to spinosad sprays did not change the toxicity of spinosad to bees in residue bioassay studies. Spinosad at as high as 500 ppm in feeders containing a sucrose/honey syrup caused no significant reduction in honey bee visitation or total syrup consumed.

   

• Toxicity of fungicides to honey bees (Hymenoptera: Apidae) and their effects on bee foraging behavior, pollen viability and fruit set on blooming apples and pears

  96-98.

  D. R. Mayer

  G. Kovács

  Views:

  175

  Fungicides fosetyl-AL, triadimefon, dodine, mycobutanil and fenarimol were tested for honey bee (Apis mellifera L.) mortality and effect on bee foraging, pollen viability and fruit set in blooming apple and pear. None of the materials were toxic to honey bees or reduced pollen gemination or fruit set.

   

• Comparison of honeybee behaviour in blooming fruit plantations

  147-151.

  P. Benedek

  J. Nyéki

  T. Szabó

  C. Konrád-Németh

  Views:

  191

  Field observations were made on the fl ower visiting behaviour of honeybee foragers in commercial fruit plantations of apricot, Japanese plums, sour cherry, apple and pear. The number of inspected cultivars was 18. The intensity of fl ower visiting by honey bees was markedly different when data of different fruit species are compared. Most intense bee activity was registered on the Japanese plums, somewhat less on apricots, the intensity diminished signifi cantly with apples and pears. Our data presented on the honeybee visitation of Japanese plums can be regarded as new fi nding because no information has been available so far on the relative attractiveness of this fruit species compared to European fruit tree species. Japanese plums were somewhat more attractive to honeybees than apricot and much more attractive than sour cherry, apple and pear. The behaviour of honeybees as visiting the blooming trees displayed specifi c differences according to the fruit species (apricot, sour cherry, pear), which coincide largely with earlier results. It is notable that the fl ower visiting behaviour of honeybees on Japanese plums has been found to be fairly similar to the same on European plums.

• Application of pollen mixing device in front of the hive entrance

  151-152.

  Z. Szalai

  Views:

  123

  The model of a pollen mixing device was tested in sunflower culture in order to detect the effectiveness in helping the out-going honey bees to carry more and different varieties of pollen grains on the body and body hairs. This model is build from line hairs of brushes facing each other that can keep and release pollen grains. The brushes are functioning as pollen receiver-transmitter units. The effectiveness was tested by examining the number and the species of the pollen grains adhered to the bees passing through the entrance. The amount of pollen and the number of pollen species on the hive with the device was significantly higher than on the control hive.

  The data were analysed by variance analysis and significant differences were found according to the number and species of pollen grains between the incoming and outgoing bees.