Survey of populations of the planthopper Hyalesthes obsoletus Sign. (Auchenorrhyncha, Cixiidae) for infection with the phytoplasma causing grapevine yellows in Germany

Abstract

H. obsoletus is the vector of grapevine yellows (Vergilbungskrankheit, VK) in Germany. Monitoring the abundance of the vector populations and their infestation with the phytoplasma associated with VK is necessary to assess the risk of disease outbreaks and field-spread. We tested planthoppers collected in four different vineyards of the Mosel River valley in Germany for infection by VK using DAS-ELISA and PCR. ELISA readings of female planthoppers were significantly higher than those of males. The proportion of positive testing H. obsoletus was higher in PCR tests compared to ELISA. The trapping method, either sweep-net or sticky-trap, had no significant influence on the proportion of planthoppers that reacted positively in PCR tests. The infestation of vineyard populations estimated by PCR varied between 7% and 34%. Batch samples, prepared from mixtures of crude planthopper extracts or from groups of 25 planthoppers, proved to be reliable for the detection of a single infected vector. For routine monitoring, we suggest PCR tests of batch samples from sticky traps.

First report of Almond witches’ broom phytoplasma1 (‘Candidatus Phytoplasma phoenicium’) causing a severe disease on nectarine and peach trees in Lebanon

“…They are normally transmitted by vegetative propagation or grafting (seedlings, scions, rootstocks) and by insect vectors. Once an infected plant is introduced into a region, most further spread of phytoplasmas occur via phloemfeeding, homopteran insects, primarily leafhoppers (family Cicadellidae) (Boudon-Padieu et al ., 1989), followed by planthoppers (Cixiidae), psyllids (Psyllidae) (Carraro et al ., 1998), and froghoppers (Cercopidae) (Davies and Eyre 1996;Weber and Maixner 1998;Jarausch et al , 2001). The rapid spread of Almond witches' broom over large geographical areas in North Lebanon also suggested the presence of an efficient vector.…”

Additive Effects Of Vertebrate Predators On Insects In A Puerto Rican Coffee Plantation

“…This work supports an earlier suggestion that birds may prevent outbreaks of this species (Wolcott 1948). Damage by Petrusa epilepsis to coffee plants has not been assessed, but some planthopper species are pests in other agricultural systems (Ghauri 1971, Kumarasinghe and Wratten 1996, Weber and Maixner 1998. In general, planthoppers can serve as vectors for diseases and cause injury to plants by extracting phloem from leaves and tender branches (Nault 1997).…”

Anatomical Injury Induced by the Eriophyid Mite Aceria anthocoptes on the Leaves of Cirsium arvense

“…It is generally accepted that arthropod vectors of phytoplasma are restricted to phloem-feeding insects (e.g. Weber and Maixner 1998). Eriophyid mites are known to transmit viruses, and one species is known as a vector of a phytoplasma (Boczek and Griffiths 1994).…”