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Preliminary studies on propagating natural mason bee (mixed Osmia cornuta and O. rufa) populations in artificial nesting media at the site for fruit orchard pollination
95-101.Views:587Preliminary field management studies were made to increase the population density of native early spring Osmia species (O. cornuta, O. rufa) at fruit tree plantations in Hungary. Initial bee activity around artificial nesting media and the population increase during consecutive years were much smaller at large commercial fruit orchards under intense chemical plant protection than in small mixed fruit plantation with moderate or low pesticide usage. Osmias accepted all the four kinds of tested artificial nesting media (reed, bamboo rods, hardwood blocks and light walling blocks with drilled holes). Reed provided the best nesting conditions so it is suggested to be used in the practice. Calculations showed that under favourable conditions more than 50 to 100 thousand incoming flights (arrivals or landings) occurred in a single day around a single bee shelter and this makes enormous number of possible bee visits at fruit tree flowers. For this reason it is strongly recommended to put simple bee shelters filled with artificial nesting media into fruit orchards. Experiences show that the population sizes of Osmias increase during consecutive years without any specific additional maintenance except providing shelters and nesting media.
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Nectar production and pollination in peach
123-126.Views:1467Observations were made at two growing sites, Siófok and Szatymaz, in the years 1998 and 1999, on 16 peach varieties. The production of nectar was measured, the foraging behaviour of bees, fruit set and the effect of exclusion of bee visits for different periods were observed systematically.
Production of nectar confirmed earlier data, 9.09 mg per flower in average. There was large variation due to variety and date of observation. Bee visits were relatively abundant. At favourable weather, 1 to 30 visits/flower/day occurred in the average. Artificial hand pollination increased fruit set, substantially. Open pollination yielded superior fruit set than self pollination, without bees. Supplementary bee pollination can be regarded to be beneficial to peach production as well.
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Effect of intensity of bee visitation and the foraging behaviour of honeybees on the fruit set and yield of apple (Malus domestica Borkh.)
31-39.Views:417Based on the results of our experiments, both the relative and the effective intensity of bee visitation were rather different depending on the cultivars as well as the time of the day. While it varied between relatively extreme values (40-80%) in the morning for the varieties examined, there were much smaller differences between the intensity of bee visitation at the afternoon, because the relative bee visitation attained 70-90% at each cultivar. These results showed that the differences arising from intensity of bee visitation of different cultivars should be taken into consideration more carefully in the morning in orchard planning and in estimating the number of honeybee colonies required.
The results showed that the greatest percentage of fruit set and the highest number of viable seeds per fruit were measured on branches of those cultivars that were most frequently visited by pure pollen gatherer bees as well as by bees collecting both nectar and pollen (mixed behaviour). The effect of pure pollen gatherers and of bees with mixed behaviour was highly significant from the statistical point of view on the fruit set and the number of viable seeds per fruit.
Those bees that were sucking nectar only from apple flowers did not proved to be effective pollinators at all. Relationship between their number and the fruit set as well as the number of viable seed per fruit were not significant because the coefficient of correlation was close to nil.
The ratio of side worker nectar gatherers was negatively correlated with the fruit set and the seed content of fruits of apple cultivars examined at both of our experimental sites, at Mosonmagyaróvár and Feketeerdő as well. The presence of side worker nectar gatherers resulted in higher decrease of fruit set and seed content of fruits at Feketeerd6 than at Mosonmagyaróvár, especially in the morning.
The effect of flower visiting intensity by other pollinating insects was found to be fairly variable according to the time of the day. In the morning they had no effect on the fruit set as well as on the seed content of fruits either at Mosonmagyaróvár or at Feketeerdo. However, at the afternoon, when their intensity was greater, the correlation was a bit stronger.
