Fieberiella florii (Stal)
Significance: Apple proliferation disease, caused by Candidatus Phytoplasma mali, is a disease of significant economic importance in parts of Europe. The phytoplasma does not occur in North America and plant propagative material of Malus is regulated by the NAPPO countries to prevent its introduction.
In parts of Europe, Candidatus Phytoplasma mali is spread mainly by the feeding of psyllid vectors, such as Cacopsylla melanoneura (Forster) and C. costalis (Flor). These insects mainly occur on apple during the winter and spring months, and then migrate to other hosts during the rest of the year. Information on other potential vectors is lacking, particularly those that might be active in apple orchards during the remainder of the year (i.e. summer and fall).
Recent laboratory studies in Italy have confirmed research by Krczal et al. (1989) that suggested Fieberiella florii (Stal) is able to transmit Candidatus Phytoplasma mali to healthy apple seedlings. This recent study used molecular methods to confirm the earlier findings. This leafhopper is reported in parts of Europe and the current study found the leafhopper during the summer months in apple orchards in Italy, thus it may also have a role in the epidemiology of the Apple proliferation phytoplasma.
In North America, F. florii is an important vector of phytoplasmas belonging to the peach X group. The insect is reported in parts of the United States and Canada. The current study substantiates phytosanitary concerns in North America over Apple proliferation disease and that if Candidatus Phytoplasma mali were ever introduced, it could be vectored by insects that are already present within North America.
Krczal G, Krczal H and Kunze L, 1989. Fieberiella Florii (Stal), a vector of apple proliferation agent. Acta Hort. (ISHS) 235:99-106. Tedeschi R and Alma A, 2006. Fieberiella florii (Homoptera: Auchenorrhyncha) as a Vector of "Candidatus Phytoplasma mali". Plant Dis. 90:284-290.