Susceptibility of raspberry cultivars to the raspberry cane midge (Resseliella theobaldi BARNES)

摘要

During the 2004 growing season, five raspberry cultivars were evaluated in termsudof their susceptibility to the raspberry cane midge (Resseliella theobaldi Barnes). Theudtrial was carried out at Berkenye, Nógrád County, Hungary. The cultivars evaluated were ‘Rubaca’ from Germany, ‘Fertődi Zamatos’ from Hungary, ‘Tulameen’ fromudCanada, and ‘Autumn Bliss’ and ‘Golden Bliss’ from the United Kingdom. Everyudother week, twenty-five split primocanes of each cultivar were randomly collected forudlaboratory examination. Data recorded for each cultivar included the mean number ofudlarvae, the mean split length, and the mean extent of bark peeling per primocane.udPearson’s linear correlation coefficients were calculated for the correlations betweenudthe annual mean number of larvae per primocane on the one hand, and the annualudcumulative mean split length per primocane and annual mean extent of bark peelingudper primocane on the other hand. There was a weak correlation between annual mean number of larvae and annual cumulative mean split length, and a stronger correlation between annual mean number of larvae and annual mean extent of bark peeling. Annual mean number of larvae per primocane and annual mean extent of bark peeling per primocane were both highest in ‘Rubaca’, which means that the number of larvae per cane largely depends on the extent of stem peeling, although longitudinal splitting may also play a role. Therefore, cultivars with hardly any bark peeling and few and small longitudinal splits can be presumed to be less susceptible to infestation by the raspberry cane midge. Using these criteria, the least susceptible of the five cultivars evaluated would be ‘Tulameen’ and ‘Fertődi Zamatos’. Further research is needed to confirm this conclusion and to gather data on other factors which affect cultivar choice for new plantations, including winter hardiness, and susceptibility to cane diseases.