Browsing by discipline "Kasvintuotannon biologia (maatalouseläintiede / mehiläistalous)"

Insect pollination increases seed production and improves the quality of the yield of various crop plants. In berry plants, such as strawberry and raspberry, the size and the quality of the fruits increase by successful insect pollination. Strawberry flowers are mainly not attractive to honeybees but raspberry is one of the main yield crops for honeybees. The aim of the study was to find out, how efficiently honeybees visit strawberry and raspberry flowers, concentrating on the honey bee visits on a single flower during one hour. Honey bees can be used as vectors of Gliocladium catenulatum to control Botrytis cinerea in strawberry and raspberry. The success of vector dissemination and its sufficiency to control Botrytis cinerea is evaluated based on flower visits. The data was collected from six farms in Eastern-Finland near to Suonenjoki, in the summer 2007. The flower visits were calculated during the flowering season of strawberry and raspberry in different weather conditions, times of the day and distances from the bee hives. Flowers were chosen randomly and they had to be open to be selected for observation. The observation time varied according to bee activity on the field. In average, honeybees visited on single strawberry flower 1.75 times per hour, and on single raspberry flower 4.27 times per hour. In both plants there were no significant differences in the flower visits according to the stage of the flowering. Time of the day (hour) correlated negatively with flower visits in both plants and temperature correlated positively to flower visits in both plants. Challenging weather conditions restricted the collecting of the data and the summer was rainy. Despite of that, honeybees visited the flowers of the both plants so that the pollination was proper and the control of Botrytis cinerea was sufficient. When planning the vector dissemination, especially in strawberry, the placement and the adequate number of bee hives should be taken into consideration. The need of nutrition should be great in the hives, to maximize the flower visits. Open brood can be inserted to hives or pollen storages can be removed from the hives to stimulate pollen collection. More information is needed on the effect of hive placement, competing plants and attractiveness of different Finnish strawberry cultivars to flower visits. It could be necessary to determine the nectar and pollen secretion of Finnish strawberry and raspberry cultivars.