The effect of spring frosts on the nectar production and the bee visitation of fruit trees

Abstract

Fruit tree species suffered very strong spring frosts in 1997 in Hungary. This caused partial or total damages at buds and flowers depending on site and time of blooming. It was demonstrated at a number of experiments that frost and cold weather also strongly affected the nectar production of surviving flowers. No or very little amount of nectar was measured in flowers first of all of early blooming fruit tree species (apricot) but also of pear and apple in some places. In spite of this fact intensive honeybee visitation was detected in the flowers of fruit trees that suffered partial frost damage only at those sites where honeybee colonies were placed in or at the experimental plantations and the lack of sufficient amount of nectar did not affected bee behaviour seriously on fruit flowers. This means that bad nectar production failed to affect bee visitation of fruit trees definitely. The reason for this was the fact that not only fruit trees but another early bee plants (wild plants, too) suffered frost damage. Accordingly, in lack of forage bees intensively searched for food at blooming fruit trees with some living flowers. Consequently, there was an acceptable yield at those plantations where bud and flower damage was not complete. Accordingly, intensive bee visitation (that is moving additional bee colonies to overpopulate fruit orchards with honeybees) can be an effective tool to decrease or eliminate the detrimental effect of spring frost on the yield of fruit trees where bud or fruit damage is not too high.

Towards an understanding of the mechanisms of tolerance: compensating for herbivore damage by enhancing a mutualism

“…No other known experimental studies have used enhancing pollination as a tool to remedy losses incurred by herbivore damage in agricultural systems. One study of pear orchards suggested anecdotally that placing additional beehives in orchards might be a strategy to compensate for losses due to frost (Benedek, 2000). In agricultural systems, plants are supplied with ample fertiliser and water, and it is expected that indirect pathways could play an important role.…”

Composition of floral nectar and its seasonal variability in sour cherry cultivars

“…Such a proportion corresponds practically to that of honey. Benedek and Nyéki (1997) stated that bee visitation was in strong correlation with the sugar concentration of nectar in the case of flowers of fruit tree cultivars.…”