ISHS Acta Horticulturae 617: Workshop on Rootstocks' Performance in Phylloxera Infested Vineyards
LONG-TERM STUDY GRAPE PHYLLOXERA SEXUPARA IN FRANCONIA |
| Authors: | G. Herrmann, J.V. Herrmann |
| Keywords: | Daktulosphaira vitifoliae, Vitis, cool climate, alates, leaf galls, radicolae |
| Abstract:
In 1996, sexuparae were recorded for the first time in the Franconian wine region. From 1996 over five successive seasons phylloxera alates were studied systematically in a heavily root phylloxera-infested vineyard. To monitor sexuparae yellow sticky traps were mounted in the canopy of the vineyard and changed weekly between July to October. In the study vineyard mass propagation of the root-galling phylloxera started at the end of June / beginning of July. Post-1996, sexuparae were found annually. Flight activity commenced at the end of July / beginning of August, while the end of flight activity showed seasonal variation in different years from mid-September to mid-October. Abundance fluctuated strongly from year to year. Maximum numbers were observed in 1997 with weekly trap catches of more than 230 sexuparae. In the abdomen of trapped animals differentiated eggs could be seen that were sometimes deposited on the trap. In Northern wine regions the occurrence of sexuparae was thought to be very unlikely due to the cooler and wetter climate. In that respect the annual appearance of sexuparae in the Franconian wine region was unexpected. Since the sexuparae occurred soon after mass propagation of the root phylloxera, it is questionable that overcrowding causes the development of sexuparae, as it is often discussed. It is not clear if sexuparae are of any importance for the dispersal of this species in the Franconian wine region. However, rootstock foliage near the trial site did not produce any leaf galls during the period of study. Only one case of phylloxera gallicoles has been observed in the Franconian wine region in 1993. | |
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