The aim of this study was the effect of the subsurface drip irrigation with nitrogen fertilization chosen asparagus cultivars on the occurrence of asparagus beetles.
The field experiment was carried out in two consecutive years (2009-2010) at Kruszyn Krajeński near Bydgoszcz. The experiment was conducted in a rando-mized block design of a two-factorial system with four replications. The first tested factor was irrigation in two following variants: non-irrigated plots (control) with hand sowing nitrogen fertilizer and subsurface drip irrigated plots with nitrogen fertigation. The second factor was associated with asparagus cultivars: 5 from USA: Apollo, Atlas, UC-157, Grande and Purple Passion, and 3 from Germany: Ramada, Rapsody and Ravel. The number of adults and larvae of both asparagus beetles was observed on every single plot area; three times during the vegetation period from July to August (beginning from the first decade of July and continuing every third week). The harvest plot area was 14,7 m2 (20 plants x 0,35m x 2,1m).
The adults and larvae of twelve-spotted asparagus beetles were more nu-merous than common asparagus beetles on tested asparagus cultivars. The adults of twelve-spotted asparagus beetles prefered subsurface drip irrigation asparagus plants: Atlas, UC-157, Grande and Rapsody, than non-irrigated plants of these cultivars. Both subsurface drip irrigation and asparagus cultivars did not affect the occurrence of larvae of this species. The adults of common asparagus beetles were significantly more numerous on the non-irrigated asparagus cultivars: Grande and Purple Passion and the larvae of this species on the cultivar Rapsody, in compari-son with subsurface drip irrigation plants of these cultivars.