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• Honeybee (Apis mellifera L.) visitation at the flowers of quince cultivars (Cydonia oblonga Mill.)

  95-102.

  P. Benedek

  T. Szabó

  J. Nyéki

  Views:

  185

  Studies were made on the bee visitation of 6 quince cultivars and on the foraging behaviour of honeybees at quince flowers for 3 consecutive years. The bee visitation was highly intense because both the plantation and its surrounding was overpopulated by honeybee colonies. Some 5.5 bee visits were counted in average at 50 opening quince flowers in 10 minutes and some 9.7 flowers were visited of the 50 ones observed meanwhile. This equals some 7 bee visits per flower per day per in good weather. Bee visitation, however, was variable and it was greatly different in the three consecutive years with fairly favourable weather. Some cultivars tended to be more and others less visited by honeybees than the others but these differences were not consequent at each occasion. No consequent relationship between the weather and the bee visitation of quince trees could be recognised. It was concluded that .other factors were responsible for the variable nature of the bee activity at quince. Most honeybees tended to collect pollen (51.6% in average for the 3 years) and usually much less gathered for nectar only (19.9%), and the rest of them were mixed behaviour foragers gathering for both (28.5%). There were some slight differences in the foraging behaviour of honeybees at some cultivars but these differences were not always consequent in consecutive years. Also the nectar production of flowers failed to affect the bee visitation and the foraging behaviour of honeybees definitely. For the variable nature of bee visitation and bee behaviour at quince flowers, supplementary pollination is needed to achieve as high set of fruits as high is required to a good crop at quince (at least 20-25% because the flower density is low of this fruit tree species). Since the intensity of bee visitation at the flowers is the only reliable estimate of the necessity of supplementary bee pollination further research is needed to explore the relationship between the number of honeybee visits and the consequent fruit set at quince.

   

• Susceptibility of European pear cultivars to Venturia pirina Aderh. infection at a variety collection in Hungary

  41-47.

  P. Benedek

  T. Szabó

  Z. Szabó

  J. Nyéki

  Views:

  293

  Field sensitivity of 271 European pear genotypes were evaluated in a large variety collection of pear in Hungary during a nine years survey. Substantial differences were detected in the rate of pear scab infection of leaves and fruits. Some 18 per cent of the inspected genotypes remained completely free of infection even in the years with weather favouring to the disease. On the other hand, 78 % of the inspected genotypes were infected in some or more extent. The rate of infection was generally higher on leaves than on fruits. 18.6 % of the genotypes inspected were tolerant to leaf infection and their majority (81.1 %) were tolerant to fruit infection. Some one fi fth of the genotypes (19.7 %) were highly susceptible to leaf infection but only minor rate of them (2.2 %) were highly susceptible to fruit infection. There were 44 genotypes that could be regarded as tolerant to pear scab leaf and fruit infection under fi eld conditions. Some of these genotypes may be suitable to commercial pear growing with highly reduced chemical control against pear but their yield capacity and fruit quality should be evaluated.

• The effect of the fruit set on the mean mass of sour cherry fruits

  17-19.

  P. Benedek

  T. Szabó

  J. Nyéki

  Views:

  279

  Experiments were conducted with four sour cherry cultivars three of that were self-fertile and one was self-sterile. Different levels of fruit set were obtained by limiting, the bee pollination period. The limitation of the duration of the effective bee pollination period definitely affected the fruit set of all the four cvs. The mass of individual fruits seemed to be related to the final set but this relationship has not find to be definitely expressed statistically at that moderate level of maximum fruit sets (10-14 per cent at the maximum) we obtained in the experiments. For this reason, further research is needed to explore that level of fruit set that can notably reduce the fruit size (mass) to an undesirable extent.