WHAT HAS CHANGED THE PHYLLOXERA, THE GRAPE OR THE ENVIRONMENT? DAMAGE ON GRAFTINGS
Grapevine phylloxera (Daktulosphaira vitifoliae Fitch) is one of the most invasive insects in viticulture. In spite of its monophagous behavior, only feeding on Euvitis subgenera species, the genetic variation within the grape phylloxera is great (Lin et al., 1999; Forneck et al., 2000; Corrie et al., 1998) even within a small, geographical area (Kocsis et al., 1998; Vorwerk and Forneck, 2006). Hungary is a good place to test phylloxera activity because both the leaf galling and root feeding forms are present. We confirmed with exclusion experiments that the first leaf galls in the early spring are created by individuals arising from the soil. Galls begin to appear at bud break and average numbers of galls per leaf increase as the season progresses. Our results suggest that the first emergence of phylloxera from the soil coincides with the first spring gallicoles. Overwintering soil dwelling nymphs becoming active at bud break result in the first infestations on the plant leaves. But we do not know whether these nymphs derive from radicicoles or from gallicoles that moved to the soil in the fall. We report gallicoles on the Vitis vinifera L. cultivars, Cardinal and Pannonia kincse.
Kocsis, L. 2009. WHAT HAS CHANGED THE PHYLLOXERA, THE GRAPE OR THE ENVIRONMENT? DAMAGE ON GRAFTINGS. Acta Hort. (ISHS) 816:35-38
phylloxera, grafting, environment, grape