Studies on biology and population dynamics of the leafhopper Psammotettix alienus Dahlb. (Homoptera: Auchenorrhyncha) as vector of Wheat dwarf virus (WDV) in Saxony-Anhalt, GermanyZur Biologic und PopulationsdynamikderZwergzikade Psammotettix alienus

摘要

Embryonic and nymph larval developments of the leafhopper Psammotettix alienus Dahlb. were studied on winter barley Hordeum vulgare L. under laboratory conditions at 20 , 70-95 % RH and 18L/6D. Its population dynamics have been observed on winter barley in field since 1999. In the field, leafhoppers were caught with sweep-net and biocoenometer with aspirator from May to November in 1999 and from April to December in 2000. Under the light microscope, seven stages of embryonic development canbe distinguished. The nymph development consists of five instars. The duration of embryonic development was 18.3 days range 16 .. 24 days, whereas nymph development lasted 32.4 days range 26 .. 39 days. In this case, average duration of 1st instar,2nd instar, 3rd instar, 4th instar and 5 instars were 5.9 days, 5.1 days, 5.6 days, 6.3 days and 9.4 days, respectively. In 1999, imago adult leafhoppers could be observed in the field from the end of May to the second week of November, while in 2000, they were recorded from the second week of May until the third week of December. That means, the occurrence of leafhoppers as well as their activities as a vector of Wheat dwarf virus WDV in cereal crops in the region Saxony-Anhalt was earlier and longer in 2000 compared to 1999. In 1999 and in 2000, the peak population density was reached in a self-sown winter barley stubble field in mid-September with 43 and 25 individuals per m2, respectively.