B. Manurung, W. Witsack, Silke Mehner, Maria Grüntzig, E. Fuchs
Embryonic and nymph (larval) developments of the leafhopper Psammotettix alienus Dahlb. were studied on winter barley (Hordeum vulgare L.) under laboratory conditions (at 20°C, 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 can be 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, 4 th instar and 5th 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 m 2, respectively. © Eugen Ulmer KG.
Martin-Luther-University Halle-Wittenberg, Institute of Zoology, D-06099 Halle (Saale), Hoher Weg 4, Germany; State University of Medan (UNIMED), Dept. of Biology-FMIPA, Medan-Estate, North-Sumatra, 20221, Indonesia; Martin-Luther-University Halle-Wittenberg, Institute of Plant Breeding and Plant Protection-Virology, D-06108 Halle (Saale), Emil-Abderhalden-Straße 27, Germany
