Young Grapevine Decline

Jay W. Pscheidt, Oregon State University

Symptoms

Young vine decline develops slowly in the first few seasons of vineyard establishment and production. Young vines generally appear normal at planting, but differences in vigor become marked: reduced trunk caliper, shortened internodes, reduced foliage/canopy fill, and reduced leaf area. During the first 3 to 5 years after planting, foliar symptoms may appear as interveinal chlorosis, followed by necrosis and early defoliation. Cross-sectional views of trunks of declining grapevines show dark brown to black streaking in the vascular elements due to plugging of individual or aggregates of xylem vessels with amber to black gum (gummosis) and formation of tyloses. A few to most vascular elements may be discolored.

Below ground, symptoms include reduced total root biomass, reduced numbers of feeder roots, and sunken, necrotic root lesions. Symptoms of young vine decline resemble other important diseases of grape including uneven wood maturity as in Pierce’s Disease, virus-induced incompatibility, esca or black measles, and some nutrient deficiencies.

Black gumming in the vascular system is necessary for diagnosis of these diseases but not sufficient as a single symptom. Black or amber streaks in the vascular elements are deposits of phenolic compounds in response to wounding, a general plant defense mechanism. Physical injuries to the grapevine due to root tearing, disbudding, or other trauma during production or planting can result in phenolic deposits and black discoloration, or even outright death of tissue as the result of injury to cambium tissues.

Cause

Young grapevine decline involves two distinct diseases: Cylindrocarpon black foot disease, caused by Cylindrocarpon obtusisporum and by C. destructans, and young esca, caused by Phaeoacremonium inflatipes, Phaeomoniella chlamydospora, and occasionally Phaeoacremonium aleophilum. Little is known about the etiology or epidemiology of these pathogens on young grapevines. These diseases affect grafted grapevines in the first 10 years of establishment and are not specific to any scion–rootstock combinations. Cylindrocarpon is soilborne and infects grapevines through natural openings or wounds on roots or other underground portions of the rootstock such as the pith. Phaeoacremonium spp. are the pathogens responsible for measles in older vines. It appears that these fungi are capable of living inside vines without producing symptoms, but have the ability to become severe pathogens as a result of poor cultural practices.

In general, many other problems have been associated with declining vines including “J” rooted vines, root girdling, graft failure, crown gall, gopher damage, early fruit load, and water stress. The latter two conditions seem to favor both black foot disease and/or young vine decline.

Cultural Control

Good management techniques such as proper planting, irrigation, and fertility for young vines while avoiding devigorating stresses both before and after planting are very important for establishing a healthy and productive vineyard.

1. When planting, sort out vines of poor quality. Do not plant vines that have been rooted from a curved cane (J-rooted), have weak or spindly growth or obvious problems such as crown gall. If you must use these vines, plant them together in rows where they can be monitored in future years.

2. Delay fruiting for several years until vines have balanced root and shoot growth. Cropping several tons in the second year after planting has been associated with these diseases.

3. Using grow tubes also has been associated with these diseases. It is suspected that grow tubes promote more shoot growth than root growth in young vines.

4. Plant new vineyards in spring or fall when water is not a limiting factor. Irrigate new plantings for a few years before switching to dryland production or beginning strict regulated deficit irrigation regimes.

Reference

Scheck, H., S. Vasquez, D. Fogle, and W.D. Gubler. 1998. Grape growers report losses to black-foot and grapevine decline. California Agriculture 52(4):19–23.