Zsuzsa Basky

Biotypic differences in Russian wheat aphid (Diuraphis noxia) between South African and Hungarian agro-ecosystems

The effect of Russian wheat aphid Diuraphis noxia(Mordvilko) from South Africa and Hungary was measured on susceptible and resistant South African wheat cultivars and a susceptible Hungarian barley cultivar. For the three cultivars (‘SST 333’, ‘Betta’, and ‘Isis’) tested in both countries, Hungarian D. noxia reduced plant weight and leaf area more than South African D. noxia and this difference increased over time. Hungarian D. noxia reduced plant weight and leaf area of the resistant wheat SST 333 more than the susceptible wheat Betta. Hungarian D. noxia also reduced plant weight of the resistant wheat ‘PI 262660’ more than the susceptible wheat Betta (although the opposite was true for leaf area). In Hungary the resistant SST 333 and PI 262660 showed similar severe symptoms of yellowing and leaf rolling as susceptible Betta. In addition, Hungarian D. noxia caused visible water imbalance in resistant wheats SST 333 and PI 262660. The differences in damage did not result from higher growth rate of Hungarian D. noxia colonies because aphid numbers did not differ consistently between countries or match the differences in damage. Differences between Hungarian and South African D. noxia suggest genetic differences between these populations. These results support the idea that resistant plant germplasm has geographical limits because of variation in agro-ecosystems.

Distribution and history of Russian wheat aphid, Diuraphis noxia (Kurdj.) in the Carpathian Basin (Hom., Aphididae)

The Carpathian Basin has been classified as one of the model areas of Russian wheat aphid (= RWA), Diuraphis noxia (Kurdj.), expansion from the southeast to Central Europe. Explorations in 2002 as well as the summarized information published earlier centered the evidence for RWA in the northern and northeastern parts of the area and its occurrence was detected and verified in the area up to the submountains of the Carpathian Mountain Range. The history and distribution peculiarities of RWA in the Carpathian Basin and area are reviewed and discussed.

Virus vector aphid activity and seed potato tuber virus infection in Hungary

An aphid and virus survey was conducted from 1993 and 1999 on the eastern lowlands in Hungary. Aphid flight was monitored with two yellow pan traps placed on the edge and in the middle of seed potato fields. From 1993 and 1997, aphid flight was monitored with a Rothamsted type suction trap. The aphid and virus survey was continued in four different regions of Hungary in 2000. Aphid flight activity recorded by the suction trap and the yellow pan traps was different. Cumulative vector intensity based on yellow pan trap catches revealed a greater variation between years than among the different locations. In 4 years out of 8, aphid flight was less intensive and quality seed potato was harvested regardless of the production site. Cumulative vector intensity is a good means to forecast the time of haulm destruction in seed potatoes.

Cereal aphid flight activity in Hungary and England compared by suction traps

Cereal aphid flight was monitored by 12.2 m suction traps at Szolnok in the middle of the Great Hungarian Plain and at Rothamsted, UK. Flight activities of Rhopalosiphum padi, Metopolophium dirbodum and Sitobion avenae were compared by the cross correlation function (CCF) between Hungary and UK. There was significant synchrony between flight a-tivity in Hungary and UK of R padi, M. dirbodum and S. avenae based on the eight years weekly sample data. The peak flight occurred 1, 3 and 2 weeks later at Rothamsted than at Szolnok for the three species (the CCF values were at – 1 week lag, r = 0.854, – 3 week lag r = 0.809, – 2 week lag r = 0.883, P < 0.05 respectively). When the flights in individual years were compared within species and between places the syn-chrony was lowest for R. padi: – in 4 years out of 8 and there was no synchrony, in the other years when synchrony occurred the time lag varied between – 1 week and – 4 weeks. For M. dirhodum the time lag varied between 1 and – 5 weeks, the synchrony was the best for S. avenae the week lag varied between 0 and – 3 weeks.Our results show that flight activity of cereal aphids at Szolnok occurs 1-3 weeks earlier than at Rothamsted. The crop season is earlier in Hungary than in England.

Flight patterns of Russian wheat aphid,Diuraphis noxia (Kurdj.) during its expansion to Central Europe (Hom., Aphididae)

Flight patterns of migrant alate Russian wheat aphids (=RWA),Diuraphis noxia (Kurdj.) during its expansion from the south-east to Central Europe were determined. Samples were taken by Rothamsted-type suction air traps in Hungary (one location, 1990–1997) and in the Czech Republic (5 locations, 1994–1998). The results document a progressive expansion of RWA, and population variation in the individual years and periods of the season. A comparison of the evidence on RWA in the individual years since its detection in Hungary and in the Czech Republic supports the presumption on the occurrence of an expansion route from the south-east (Turkey) to Central Europe. This expansion is classified as an adventive route of the over-all expansion that has covered the whole West-Mediterranean (South Europe, North Africa).