Individual number change of Empoasca spp. cicadas species in potato.

ABSTRACT

We investigated the individual number change of Empoasca spp. cicadas species that are living in potatoes for 3 years. We applied the "100 plants" method for the determination for the individual number once per week. Based on the data determined that the settling of adult begins on the last days of May, and valid presence will be followed till the end of the breeding-season. The individual number was gradually increased during the settling, and reached the peak in 1990 on 23 July, in 2000 on 6 August and in 2001 on 22 July. We determined the individuals gathered during the collection. In the population of Empoasca spp. The E. solani Curtis and the E. decipiens Paoli played the dominant role. The E. vitis Göthe was also present with insignificant individual number. Beside the adults many larvae and nymphs were living on the potato which means that the Empoasca spp. Can reproduce also on the potato. At the time of peak individual number in 1999 1876 larvae, 344 nymphs and 400 adults were present on 100 plants, in 2000 (according to the previous order) 3340, 580, 1280, and in 2001 there were 954, 786 and 285. The rainfall in Hungary was disadvantageous in the investigated period, especially the year 2000. During the rain-free period the temperature was high and the relative humidity of the air was low. However, we could state that the increase of the cicada individual number was not restrained by the heat (30-35 degrees C) days. The decrease was in connection with the ageing of the plant stock.