INCIDENCE AND POPULATION FLUCTUATION OF DIURAPHIS-NOXIA IN HUNGARY

A yellow water pan trap was used to collect Diuraphis noxia (Mordvilko ) in Central Hungary in 1989. In 1990 a Rothamsted-type suction trap c ollected 31 individuals. A D. noxia infestation was found in an autumn -sown wheat field in October 1990. The D. noxia population that overwi ntered was holocyclic. The life-span of fundatrices was 43.2 days at 1 8-22-degrees-C. The number of nymphs produced per fundatrix was 46.6. Average progeny numbers of first-generation apterae and alatae were 29 .4 and 21.4, respectively. Second-generation apterae produced an avera ge of 48.8 nymphs; 35.9% of nymphs were alatiform. The D. noxia popula tion reached its peak on 3 July in the field, at which time the mean n umber of individuals per wheat plant was 3953.6. By 20 July, the wheat plants had matured and the D. noxia colonies had disappeared from the wheat.