Individual and combined effects of Enterobacter aerogenes and metalaxyl on apple tree growth and phytophthora crown and root rot symptom development

1993 ◽  
Vol 25 (8) ◽  
pp. 975-979 ◽  
Author(s):  
C.A. Lévesque ◽  
J.D. Holley ◽  
R.S. Utkhede
Keyword(s):  
Tree Growth ◽  
Root Rot ◽  
Apple Tree ◽  
Enterobacter Aerogenes ◽  
Combined Effects ◽  
Symptom Development ◽  
Crown And Root Rot

scholarly journals Activity of metalaxyl-M+mancozeb, fosetyl-Al, and phosphorous acid against Phytophthora crown and root rot of apricot and cherry caused by Phytophthora palmivora

2017 ◽  
Vol 53 (No. 4) ◽  
pp. 216-225 ◽  
Author(s):  
Türkölmez Şahimerdan ◽  
Derviş Sibel
Keyword(s):  
Root Rot ◽  
Foliar Spray ◽  
Phosphorous Acid ◽  
Crown Rot ◽  
Phytophthora Palmivora ◽  
Symptom Development ◽  
Greenhouse Experiments ◽  
Oomycete Pathogen ◽  
Crown And Root Rot ◽  
And Control

Crown and root rot, caused by the Oomycete pathogen Phytophthora palmivora, has become a destructive disease of apricot and cherry in eastern Turkey. There are no currently registered fungicides labeled for its control. In greenhouse experiments conducted in 2012 and 2013, 1-year-old potted apricot rootstock Zerdali and cherry rootstock Mahaleb plants were treated either with foliar spray of fosetyl-Al (140, 160, and 180 g a.i./100 l) or phosphorous acid (187.5, 200, and 215 g a.i./100 l) or soil drench of 100 ml of metalaxyl-M (= mefenoxam)+mancozeb (12+192, 16+256, and 20+320 g a.i./100 l) one day after wound inoculation of crowns and roots. In both years, phosphorous acid at 200 and 215 g a.i./100 l, fosetyl-Al at 160 and 180 g a.i./100 l, and metalaxyl-M+mancozeb at 20+320 g a.i./100 l significantly reduced the root rot severity on Zerdali by 70.68–80.00% and crown rot severity on both Zerdali and Mahaleb, by 68.32–91.96 and 74.21–82.60%, respectively, compared with phosphorous acid at 187.5 g a.i./100 l, fosetyl-Al at 140 g a.i./100 l, metalaxyl-M+mancozeb at 12+192 and 16+256 g a.i./100 l and control. Moreover, fosetyl-Al at 180 g a.i./100 l and metalaxyl-M+mancozeb at 20+320 g a.i./100 l significantly reduced the root rot severity on Mahaleb compared to fosetyl-Al at 140 and 160 g a.i./100 l, metalaxyl-M+mancozeb at 12+192 and 16+256 g a.i./100 l, phosphorous acid treatments and control in 2012, providing the best control of the disease by 88.00–90.68%. Two/three phosphorous acid foliar applications at 200 g a.i./100 l suppressed symptom development when field applications were made on a curative basis in 2014 and 2015.

EVALUATION OF ALFALFA CULTIVARS FOR REACTION TO CROWN AND ROOT ROT

1985 ◽  
Vol 65 (1) ◽  
pp. 95-98 ◽  
Author(s):  
R. MICHAUD ◽  
C. RICHARD
Keyword(s):  
Disease Severity ◽  
Root Rot ◽  
Dry Matter ◽  
Forage Yield ◽  
Dry Matter Yield ◽  
Crown And Root Rot ◽  
Disease Free

Fourteen alfalfa cultivars were grown for 2 yr at three locations and evaluated for forage dry matter yield and crown and root rot. Significant differences were found among cultivars for dry matter yield. All cultivars were affected by crown and root rot, most cultivars showing between 20 and 30% of infected tissues. Differences were observed among as well as within the cultivars for disease severity. The frequency of disease-free plants was less than 1.3% of the plants evaluated. Correlation between root rot index and forage yield was −0.87 [Formula: see text] when data were pooled over years and locations.Key words: Lucerne, root rot, cultivar, yield

scholarly journals Soil Inoculum Production, Survival, and Infectivity of the Boxwood Blight Pathogen, Calonectria pseudonaviculata

Plant Disease ◽  
2015 ◽  
Vol 99 (12) ◽  
pp. 1689-1694 ◽  
Author(s):  
Norm Dart ◽  
Chuanxue Hong ◽  
Caryn Allen Craig ◽  
J. T. Fry ◽  
Xinran Hu
Keyword(s):  
Root Rot ◽  
Soil Inoculum ◽  
Foliar Blight ◽  
High Inoculum ◽  
Inoculum Production ◽  
Foliar Pathogen ◽  
Leaves And Roots ◽  
Crown And Root Rot ◽  
Stem Cankers

Boxwood blight caused by Calonectria pseudonaviculata is typically expressed as a foliage disease with aboveground symptoms including defoliation, dieback and formation of dark narrow stem cankers. Whether this pathogen behaves like other Calonectria spp. and has a significant soil phase in the epidemiology of boxwood blight is not known. In this study we observed experimentally that (1) the boxwood blight pathogen consistently forms microsclerotia in artificially inoculated leaves and roots of Buxus spp., (2) soil artificially inoculated with conidia and microsclerotia of this pathogen can cause foliar blight, (3) conidia and microsclerotia can remain viable in soil for up to 3 and at least 40 weeks, respectively (4) and the pathogen can cause crown and root rot to plants only when roots and crowns are directly exposed to relatively high inoculum levels. Our results suggest that C. pseudonaviculata is primarily a foliar pathogen with a potentially epidemiologically significant soil phase.

scholarly journals Rhizospheric bacteria as potential biocontrol agents against Fusarium wilt and crown and root rot diseases in tomato

2021 ◽  
Author(s):  
Md. Masudur Rahman Khalil ◽  
Rosario Alicia Fierro-Coronado ◽  
Ofelda Peñuelas-Rubio ◽  
Alma Guadalupe Villa-Lerma ◽  
Rigoberto Plascencia-Jatomea ◽  
...  
Keyword(s):  
Fusarium Wilt ◽  
Root Rot ◽  
Biocontrol Agents ◽  
Rhizospheric Bacteria ◽  
Crown And Root Rot

scholarly journals Sensitivity of Rhizoctonia solani AG-2-2 from Sugar Beet to Fungicides

Plant Disease ◽  
2016 ◽  
Vol 100 (12) ◽  
pp. 2427-2433 ◽  
Author(s):  
Sahar Arabiat ◽  
Mohamed F. R. Khan
Keyword(s):  
Sugar Beet ◽  
Rhizoctonia Solani ◽  
Root Rot ◽  
The United States ◽  
Damping Off ◽  
Growth Assay ◽  
The Mean ◽  
Crown And Root Rot ◽  
Mean Concentration

Rhizoctonia damping-off and crown and root rot caused by Rhizoctonia solani are major diseases of sugar beet (Beta vulgaris L.) worldwide, and growers in the United States rely on fungicides for disease management. Sensitivity of R. solani to fungicides was evaluated in vitro using a mycelial radial growth assay and by evaluating disease severity on R. solani AG 2-2 inoculated plants treated with fungicides in the greenhouse. The mean concentration that caused 50% mycelial growth inhibition (EC50) values for baseline isolates (collected before the fungicides were registered for sugar beet) were 49.7, 97.1, 0.3, 0.2, and 0.9 μg ml−1 and for nonbaseline isolates (collected after registration and use of fungicides) were 296.1, 341.7, 0.9, 0.2, and 0.6 μg ml−1 for azoxystrobin, trifloxystrobin, pyraclostrobin, penthiopyrad, and prothioconazole, respectively. The mean EC50 values of azoxystrobin, trifloxystrobin, and pyraclostrobin significantly increased in the nonbaseline isolates compared with baseline isolates, with a resistant factor of 6.0, 3.5, and 3.0, respectively. Frequency of isolates with EC50 values >10 μg ml−1 for azoxystrobin and trifloxystrobin increased from 25% in baseline isolates to 80% in nonbaseline isolates. Although sensitivity of nonbaseline isolates of R. solani to quinone outside inhibitors decreased, these fungicides at labeled rates were still effective at controlling the pathogen under greenhouse conditions.

scholarly journals Integrated Control of Rhizoctonia Crown and Root Rot of Sugar Beet with Fungicides and Antagonistic Bacteria

Plant Disease ◽  
2001 ◽  
Vol 85 (7) ◽  
pp. 718-722 ◽  
Author(s):  
Sebastian Kiewnick ◽  
Barry J. Jacobsen ◽  
Andrea Braun-Kiewnick ◽  
Joyce L. A. Eckhoff ◽  
Jerry W. Bergman
Keyword(s):  
Sugar Beet ◽  
Root Rot ◽  
Integrated Control ◽  
The United States ◽  
Field Trials ◽  
Sugar Yield ◽  
Economic Losses ◽  
Yield Increase ◽  
Leaf Stage ◽  
Crown And Root Rot

Rhizoctonia crown and root rot, caused by the fungus Rhizoctonia solani AG 2-2, is one of the most damaging sugar beet diseases worldwide and causes significant economic losses in more than 25% of the sugar beet production area in the United States. We report on field trials in the years 1996 to 1999 testing both experimental fungicides and antagonistic Bacillus sp. for their potential to reduce disease severity and increase sugar yield in trials inoculated with R. solani AG 2-2. Fungicides were applied as in-furrow sprays at planting or as band sprays directed at the crown at the four-leaf stage, or four- plus eight-leaf stage, while bacteria were applied at the four-leaf stage only. The fungicides azoxystrobin and tebuconazole reduced crown and root rot disease by 50 to 90% over 3 years when used at rates of 76 to 304 g a.i./ha and 250 g a.i./ha, respectively. The disease index at harvest was reduced and the root and sugar yield increased with azoxystrobin compared with tebuconazole. The combination of azoxystrobin applied at 76 g a.i./ha and the Bacillus isolate MSU-127 resulted in best disease reduction and greatest root and sucrose yield increase.

Sign in / Sign up

Export Citation Format

Share Document