Protective and curative grape black rot control potential of pyraclostrobin and myclobutanil

2011 ◽  
Vol 118 (5) ◽  
pp. 161-167 ◽  
Author(s):  
Daniel Molitor ◽  
Ottmar Baus ◽  
Beate Berkelmann-Löhnertz
Keyword(s):  
Black Rot ◽  
Control Potential ◽  
Grape Black Rot

Use of systems analysis to develop plant disease models based on literature data: grape black-rot as a case-study

2014 ◽  
Vol 141 (3) ◽  
pp. 427-444 ◽  
Author(s):  
Vittorio Rossi ◽  
Giovanni Onesti ◽  
Sara E. Legler ◽  
Tito Caffi
Keyword(s):  
Systems Analysis ◽  
Plant Disease ◽  
Disease Models ◽  
Black Rot ◽  
Grape Black Rot

scholarly journals Composition and evaluation of a novel web-based decision support system for grape black rot control

2015 ◽  
Vol 144 (4) ◽  
pp. 785-798 ◽  
Author(s):  
Daniel Molitor ◽  
Barbara Augenstein ◽  
Laura Mugnai ◽  
Pietro Antonello Rinaldi ◽  
Jorge Sofia ◽  
...  
Keyword(s):  
Decision Support ◽  
Decision Support System ◽  
Support System ◽  
Black Rot ◽  
Web Based ◽  
Grape Black Rot

scholarly journals A Cumulative Degree-Day-Based Model to Calculate the Duration of the Incubation Period of Guignardia bidwellii

Plant Disease ◽  
2012 ◽  
Vol 96 (7) ◽  
pp. 1054-1059 ◽  
Author(s):  
Daniel Molitor ◽  
Cathleen Fruehauf ◽  
Ottmar Baus ◽  
Beate Berkelmann-Loehnertz
Keyword(s):  
Incubation Period ◽  
Present Model ◽  
Developmental Stages ◽  
Black Rot ◽  
Phenological Stage ◽  
Degree Days ◽  
Fungal Development ◽  
Guignardia Bidwellii ◽  
Degree Day ◽  
Grape Black Rot

The duration of the incubation period of Guignardia bidwellii on leaves and clusters of Vitis vinifera strongly correlates to temperature. To describe this relationship mathematically, a new, cumulative degreeday- based model was developed. According to this model, first symptoms on leaves appear after reaching a threshold of 175 cumulative degree-days (calculated as the sum of average daily temperatures between 6 and 24°C starting on the day after the infection). On clusters, the duration of the incubation period is additionally affected by their respective developmental stages. For ‘Riesling’, the duration of the incubation period on clusters corresponds to the duration on leaves until reaching the phenological stage “berries beginning to touch“ but extends continuously with ongoing phenological development. Therefore, a correction factor recognizing cluster phenology was derived to calculate the cumulative degree-day thresholds for the occurrence of first symptoms on clusters after reaching “majority of berries touching”. Hence, this present model allows the estimation of fungal development and forecasts the appearance of new symptoms on leaves as well as on clusters, enabling growers to more precisely schedule curative as well as protective fungicide applications against grape black rot.

scholarly journals Factors Influencing the Efficacy of Myclobutanil and Azoxystrobin for Control of Grape Black Rot

Plant Disease ◽  
2003 ◽  
Vol 87 (3) ◽  
pp. 273-281 ◽  
Author(s):  
Lisa Emele Hoffman ◽  
Wayne F. Wilcox
Keyword(s):  
Black Rot ◽  
Alternative Respiration ◽  
Complete Control ◽  
Guignardia Bidwellii ◽  
Factors Influencing ◽  
Grape Black Rot ◽  
History Of ◽  
Commercial Vineyard ◽  
Strobilurin Fungicide

We studied several factors influencing the efficacy of the demethylation inhibitor (DMI) fungicide myclobutanil and the strobilurin fungicide azoxystrobin for control of grape black rot, caused by the pathogen Guignardia bidwellii (anamorph Phyllosticta ampelicida). The distribution of sensitivities to myclobutanil among G. bidwellii isolates from an “organic” vineyard (no previous exposure to synthetic fungicides, n = 50) and from a commercial vineyard with a history of DMI applications (n = 60) was determined in vitro. There was little difference between the two populations, and the range of sensitivities was narrow; for the composite population of 110 isolates, the value of the mean effective dose for 50% inhibition (ED50) was 0.04 mg/liter, and the most- and least-sensitive isolates were separated by a factor of 16. When applied from 2 to 6 days after inoculating grape seedlings with a suspension containing either 2 × 104 or 1 × 106 conidia per ml, myclobutanil (60 mg/liter) provided complete control of lesion development. When applied beyond 6 days after inoculation but prior to lesion appearance (9 to 11 days after inoculation, depending on temperature), it provided complete control of pycnidium production in those lesions that developed subsequently. In contrast, when applied 2 to 10 days after inoculation with 2 × 104 conidia per ml, azoxystrobin (128 mg/liter) provided only 78 to 63% control of lesion formation and erratic control of pycnidium formation, although conidium production was reduced by 85 to 68% across this range of treatments. Relatively little control was provided by azoxystrobin treatments following inoculation with 1 × 106 conidia per ml. On leaf disks treated with azoxystrobin at 20 mg/liter prior to inoculation, 8 to 43% of conidia from five G. bidwellii isolates germinated, and 4 to 19% formed appressoria. However, these processes were completely to near-completely inhibited when salicylhydroxamic acid (SHAM), which inhibits an alternative respiration pathway utilized to circumvent the activity of strobilurin fungicides, was added to the inoculum at 100 mg/liter. Thus, alternative respiration apparently allowed the conidia to germinate and form appressoria on azoxystrobin-treated leaves. When grape seedlings were sprayed with commercially formulated azoxystrobin at 200 mg/liter and inoculated the next day with G. bidwellii conidia, little or no disease was evident 4 weeks later. However, G. bidwellii pycnidia formed on up to 50% of the leaves from such plants when they were killed with paraquat 1 to 7 days after inoculation. These results suggest that latent infections became established on azoxystrobin-treated leaves and became active after the plants were killed with paraquat.

Simulating the susceptibility of clusters to grape black rot infections depending on their phenological development

2011 ◽  
Vol 30 (12) ◽  
pp. 1649-1654 ◽  
Author(s):  
Daniel Molitor ◽  
Beate Berkelmann-Loehnertz
Keyword(s):  
Black Rot ◽  
Grape Black Rot

scholarly journals Production of Pycnidia and Conidia by Guignardia bidwellii, the Causal Agent of Grape Black Rot, as Affected by Temperature and Humidity

2017 ◽  
Vol 107 (2) ◽  
pp. 173-183 ◽  
Author(s):  
G. Onesti ◽  
E. González-Domínguez ◽  
V. Rossi
Keyword(s):  
Field Experiments ◽  
Growth Parameters ◽  
Effect Of Temperature ◽  
Black Rot ◽  
High Humidity ◽  
Guignardia Bidwellii ◽  
Leaf Lesion ◽  
Grape Black Rot ◽  
Effects Of Temperature ◽  
Grape Leaf

Black rot, caused by the fungus Guignardia bidwellii, is a polycyclic disease affecting grape leaves and berries. In environmentally controlled experiments and in a 3-year field study, the effects of temperature and relative humidity (RH) were assessed on the following growth parameters of G. bidwellii: (i) formation of pycnidia and cirri in grape leaf lesions, (ii) production and germination of conidia, and (iii) length of the period between lesion appearance and pycnidia production. Pycnidia were produced between 5 and 35°C and at 90 to 100% RH but more pycnidia were produced between 20 and 30°C. No pycnidia were produced at RH < 90%. The first pycnidia were produced in approximately 2 days after lesion appearance at ≥20°C and in 8 days at 5°C; pycnidia continued to be produced on the same lesion for 5 to 16 days after lesion appearance, depending on the temperature. Models were developed to describe the effect of temperature and RH on pycnidia production, accounting for 95 and 97% of variability, respectively. Cirri were extruded only between 15 and 35°C and mainly at 100% RH. Field experiments confirmed that pycnidia are produced for several days on a leaf lesion and that the length of the period between lesion appearance and pycnidia production depends on temperature. Overall, the findings showed that production of conidia requires high humidity; under field conditions, some hours at high humidity, which usually occur at nighttime, rather than constant high humidity may be sufficient.

Sign in / Sign up

Export Citation Format

Share Document