scholarly journals Root Collar Excavation for Postinfection Control of Armillaria Root Disease of Grapevine

Plant Disease ◽  
2004 ◽  
Vol 88 (11) ◽  
pp. 1235-1240 ◽  
Author(s):  
Kendra Baumgartner
Keyword(s):  
Vascular Tissue ◽  
Severe Disease ◽  
Root Disease ◽  
Armillaria Mellea ◽  
Cultural Approach ◽  
Early Stages ◽  
Armillaria Root Disease ◽  
Shoot Weight ◽  
Soil Excavation ◽  
Root Collar

Root collar excavation for control of Armillaria root disease of grapevine was investigated in two California vineyards (vineyard K1 and vineyard N1) from 2002 to 2004. The hypothesis tested was that root collar excavation, when timed in early stages of root collar infection, may cause mycelial fans of the pathogen Armillaria mellea to recede from the root collar before severe disease results from vascular tissue decay. In vineyard N1, excavation significantly increased yield and cluster weight of symptomatic grapevines; symptomatic-excavated grapevines had the same high mean cluster weight as healthy grapevines, and there were no significant effects of excavation on yield or pruning weight of healthy grapevines. In vineyard K1, where excavated root collars frequently refilled with soil, excavation had no significant effects on yield or pruning weight of symptomatic grapevines, and significantly reduced pruning weight and shoot weight of healthy grapevines. Reexamination in March 2004 revealed that mycelial fans had receded from root collars of symptomatic-excavated grapevines, but remained on root collars of symptomatic-nonexcavated grapevines. Root collar excavation appears to be a promising cultural approach for control of Armillaria root disease, as long as excavated root collars are kept clear of soil.

Armillariaostoyae in young spruce plantations

1990 ◽  
Vol 20 (11) ◽  
pp. 1773-1778 ◽  
Author(s):  
William H. Livingston
Keyword(s):  
Black Spruce ◽  
Lateral Roots ◽  
White Spruce ◽  
Root Disease ◽  
Stem Height ◽  
Conifer Seedlings ◽  
Armillaria Root Disease ◽  
Root Collar

Black spruce (Piceamariana (Mill.) B.S.P.) and white spruce (P. glauca (Moench) Voss) plantations, 4–10 years old, were examined for Armillaria root disease. The disease was found in 89% of 27 sample locations, and up to 2% of the trees were recently killed. Armillariaostoyae (Romagn.) Herink was the cause of the disease. Spruce show little reduction in stem height and diameter prior to being killed by the fungus. Lethal infections of A. ostoyae develop primarily at the root collar and are associated with root deformities and small diameters of lateral roots. Root deformities, frequently associated with growing conifer seedlings in containers, are hypothesized to predispose planted spruce to Armillaria root disease.

scholarly journals A Soil Inoculant Inhibits Armillaria mellea In Vitro and Improves Productivity of Grapevines with Root Disease

Plant Disease ◽  
2006 ◽  
Vol 90 (4) ◽  
pp. 439-444 ◽  
Author(s):  
Kendra Baumgartner ◽  
Amy E. Warnock
Keyword(s):  
Therapeutic Benefit ◽  
Quality Parameters ◽  
Root Disease ◽  
Soluble Solids ◽  
Juice Quality ◽  
Comamonas Testosteroni ◽  
Armillaria Mellea ◽  
Soil Inoculant ◽  
Armillaria Root Disease

A soil inoculant, Vesta (Biologically Integrated Organics, Inc., Sonoma, CA), was tested for its ability to inhibit Armillaria mellea, causal agent of Armillaria root disease of grapevine (Vitis vinifera). Colony diameter of A. mellea was significantly inhibited by undiluted inoculant (P < 0.0001) and by bacterial isolates cultured from the inoculant (Bacillus subtilis, B. lentimorbus, Comamonas testosteroni, Pseudomonas aeruginosa, P. mendocina; P < 0.0001) relative to diameter of the nontreated control. Efficacy of the inoculant for postinfection control of Armillaria root disease of grapevine was examined in an A. mellea-infested vineyard in northern California. Inoculant was applied via drip-irrigation to vine rows in replicate blocks in 2003 and 2004. Yield, growth, mineral nutrition, and juice quality parameters of healthy and symptomatic vines were measured in treated and nontreated vine rows. Significantly decreased petiole P and K concentrations and significantly lower soluble solids content in fruit from symptomatic vines demonstrated that Armillaria root disease negatively affects vine mineral nutritional status and fruit quality, findings that have not been previously reported for an agronomic host of A. mellea. The inoculant significantly increased cluster weights of symptomatic vines (109.63 g/cluster), relative to those of symptomatic-nontreated vines (92.05 g/cluster), to levels comparable to those of healthy vines (122.09 g/cluster). However, the inoculant did not decrease the rate of symptom development or mortality of treated vines from 2002 to 2004. The results of our field experiment suggest that the inoculant may not prevent Armillaria root disease, but can provide therapeutic benefit by improving productivity of infected vines.

scholarly journals Spatial Distribution of Armillaria mellea in Pear Orchards

Plant Disease ◽  
1998 ◽  
Vol 82 (11) ◽  
pp. 1226-1231 ◽  
Author(s):  
D. M. Rizzo ◽  
E. C. Whiting ◽  
R. B. Elkins
Keyword(s):  
Spatial Distribution ◽  
Sensu Stricto ◽  
Root Disease ◽  
Lake County ◽  
Somatic Incompatibility ◽  
Armillaria Mellea ◽  
Primary Means ◽  
Armillaria Root Disease ◽  
Root Contact

Pears have traditionally been considered to be highly resistant to Armillaria root disease (causal agent: Armillaria mellea). In recent years, however, the incidence of Armillaria root disease in pears has increased in California. To determine the spatial distribution of Armillaria root disease in the field, a total of 156 isolates of Armillaria were collected from dead and dying pear trees located within two orchards in Lake County. All isolates from these two orchards, as well as from an additional 10 pear orchards, were identified as Armillaria mellea sensu stricto. Based on pairings among 102 Armillaria isolates, four somatic incompatibility groups (SIGs) were identified at orchard 1. Three of the four SIGs at this site were over 100 m in length; the largest SIG was at least 200 m in length. Pairings among 54 isolates identified five SIGs at orchard 2. The SIGs at orchard 2 were generally smaller than those detected at orchard 1 and ranged from 20 to 60 m in length. The size of the SIGs points toward long-term establishment of the fungus on the two sites, most likely predating the establishment of the pear orchards. Extensive root excavations of 19 trees indicated that the primary means of secondary spread of Armillaria was via rhizomorphs, as opposed to root-to-root contact.

scholarly journals Armillaria Root Disease Inoculum Remaining in Young Ontario Conifer Plantations Following Root Raking or Madge Rotoclearing

1998 ◽  
Vol 15 (4) ◽  
pp. 191-196 ◽  
Author(s):  
Johann N. Bruhn ◽  
Jeanne D. Mihail ◽  
Timothy R. Meyer
Keyword(s):  
Woody Debris ◽  
Site Preparation ◽  
Root Disease ◽  
Northern Ontario ◽  
Fallow Period ◽  
Disease Mortality ◽  
Lethal Infection ◽  
Woody Root ◽  
Armillaria Root Disease ◽  
Apparently Healthy

Abstract Armillaria ostoyae causes a destructive root disease in northern conifers. Most infections result from root invasions by rhizomorphs growing through the soil from previously colonized stump and woody root debris. Armillaria longevity in woody debris is related to the colonized volume. Stump and root removal by root raking alone often does not satisfactorily reduce subsequent root disease mortality. This investigation characterized residual woody debris volumes in three conifer seed orchards in northern Ontario. Site preparation for stump and root removal in two of the orchards consisted of root raking alone, vs. Madge Rotoclear™ treatment ("rotoclearing") in the third orchard. Fallow periods between site preparation and planting were 1, 5, and 8 yr in the three orchards, respectively. Mortality related to colonized residual woody debris is continuing in the raked orchards, but appears to have ended in the rotocleared orchard. Root systems of 32 orchard trees recently killed by Armillaria root disease and 9 apparently healthy (otherwise comparable) trees were excavated. Regardless of site preparation method, Armillaria-killed trees were associated with greater total volumes of residual woody debris (comprising larger pieces on average) than were healthy trees. Also, healthy trees in the rotocleared orchard were associated with smaller debris pieces on average than were healthy trees in the root-raked orchard. Size of individual woody debris pieces which contained viable A. ostoyae was highly variable. Even small pieces of colonized debris close to a root crown were apparently capable of causing lethal infection. Nevertheless, compared to root raking, rotoclearing apparently breaks A. ostoyae-colonized woody debris into smaller pieces resulting in more rapid displacement of A. ostoyae. We conclude that rotoclearing followed by a fallow period of 8 yr before planting merits consideration as an inoculum reduction treatment for site preparation. A 10 yr fallow period might have prevented nearly all root disease mortality under the conditions of this study. North. J. Appl. For. 15(4):191-196.

scholarly journals Inoculum Reduction Measures to Manage Armillaria Root Disease in a Severely Infected Stand of Ponderosa Pine in South-Central Washington: 35-Year Results

2012 ◽  
Vol 27 (1) ◽  
pp. 25-29 ◽  
Author(s):  
Charles G. Shaw ◽  
D.W. Omdal ◽  
A. Ramsey-Kroll ◽  
L.F. Roth
Keyword(s):  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Root Disease ◽  
Intensive Treatment ◽  
Control Treatment ◽  
No Removal ◽  
South Central ◽  
Armillaria Root Disease ◽  
Different Levels ◽  
Maximum Removal

Abstract A stand of ponderosa pine (Pinus ponderosa) severely affected by Armillaria root disease was treated with five different levels of sanitation by root removal to reduce root disease losses in the regenerating stand. Treatments included the following: (1) all trees pushed over by machine, maximum removal of roots by machine ripping, and visible remaining roots removed by hand; (2) all trees pushed over by machine and maximum removal of roots by machine ripping; (3) all trees pushed over by machine with no further removal of roots; (4) smaller trees pushed over by machine but large stumps left, otherwise maximum removal of roots by machine ripping; and (5) all trees felled and removed by skidding, area cleared of slash, sod scalped, and no removal of roots. After 35 years, we found that the more intense and thorough root-removal treatments were generally more effective in reducing the occurrence of Armillaria root disease. However, even the most intensive treatment (treatment 1), which experienced significantly less disease than most other treatments, had 23% of the area expressing mortality. The only operationally feasible treatment (treatment 3) also reduced levels of mortality, but not significantly (40% mortality versus 52% in the control, treatment 5). Although these results support the concept that inoculum removal can reduce root disease levels, the treatment necessary to provide a meaningful reduction in disease loss does not seem to warrant its cost.

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