Preliminary survey on putative insect vectors for Rubus stunt phytoplasmas
Phytoplasmas are cell wall‐less phytopathogenic bacteria which are associated with a disease in Rubus species known as Rubus stunt. Symptoms range from stunting, witches’ broom, small leaves, short internodes, enlarged sepals, phyllody and flower proliferation to fruit malformations. Phytoplasmas can be spread by vegetative propagation and by phloem‐feeding insect vectors. However, little is known about the spectrum and distribution of putative Rubus stunt insect vectors. In this study, a screening of putative insect vectors of Rubus stunt in raspberry plantations in southern and northern Germany was carried out during two successive years (2014 and 2015) with multiple sampling dates throughout the growing seasons. A total of 2,891 hemipteran insects were sorted, identified to family, genus or species level when possible, and a subset of 319 DNA samples containing a sum of 932 selected individuals representing all identified species, sampling locations and sampling dates were tested for phytoplasma DNA using qPCR. Altogether, eight DNA samples were positive for phytoplasma DNA, among them species from the genera Euscelidius, Macrosteles, Euscelis, Anaceratagalliaand Psammotettix. These data will form the basis for choosing and timing appropriate control measures against Rubus stunt and also for potential insect vector transmission experiments.
Publisher URL: https://onlinelibrary.wiley.com/doi/abs/10.1111/jen.12605