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Daktulosphaira vitifoliae (Fitch, 1851) - (grape phylloxera)
This species is widely distributed and a notorious pest of grapevine, especially on European vine varieties. It was accidentally introduced into Europe from North America in the 1860s, causing devastating outbreaks and nearly destroying the French wine industry in the late 1800s. Resistant rootstocks derived from native American Vitis species are the main means of control. Another serious outbreak developed in California in the 1980s when the pest overcame resistant hybrid rootstocks.
The aphid-like insect is very small (less than 1 mm as adult) and has a complex life cycle with various forms. The asexual leaf-feeding form starts with overwintering eggs. These develop into females in spring which feed on the shoots, cause spherical galls on the underside of the leaves, and reproduce parthenogenetically inside the galls. The young crawlers leave the galls and most of them establish new galls. About 3-5 generations might develop on the leaves. However, some crawlers drop to the ground and start similar cycles on the roots. Nymphs can also overwinter on the roots. An abundance of root galls (tuberosities) can cause serious damage to the plant and result in the invasion of secondary pathogens. Death of the vine can follow. The portion of leaves or roots attacked depends on the species and varieties of grapes.
During the summer, winged forms can develop from the root-feeding form and disperse. They lay either small eggs which develop into males or large eggs becoming females. These sexual forms mate and the females lay eggs under the bark of vines which overwinter.
|• English:||grape phylloxera|
|• Français:||phylloxéra de la vigne|