Diseases of grape (
Root-knot nematode
Grapes in Arizona are infected by several plant parasitic nematodes, including Meloidogyne incognita, the root-knot nematode. Root-knot nematode has a very wide host range and is able to reproduce on most of the agronomic crops and vegetables grown in Arizona except alfalfa and oats. Severe infections in grape cause yellowing and stunting. Roots have typical swellings or galls. These swellings are especially noticeable on small roots. Other parasitic nematodes cause loss of vigor or decline, but can only be positively identified in laboratory analysis of soils. In the low desert, heavily infected plants may die in late summer and fall.
Once vines are infected, control is very difficult. Cultural practices such as addition of manures and other soil amendments, improved tilth and drainage, general pest control and good irrigation practices that increase plant vigor may reduce the effects of nematode infection. Chemical controls include post-plant chemical nematicides Fenamiphos or Enzone; check the label for rates and application times. Only clean planting material should be used for plant establishment, and previously cultivated soils should be tested for parasitic nematodes before planting. Pre-plant soil fumigation is necessary if planting into infested soils.
For more information , see the following web sites:
http://www.ipm.ucdavis.edu/PMG/r302200111.html
September 20, 2002