scholarly journals THE EFFECT OF POST PLANT SOIL SOLARIZATION ON BLACK ROT OF 'CARLOS' MUSCADINE GRAPE

HortScience ◽  
1992 ◽  
Vol 27 (11) ◽  
pp. 1169f-1169
Author(s):  
C. Stevens ◽  
V. A. Khan ◽  
J. Y. Lu ◽  
M. A. Wilson ◽  
Z. Haung ◽  
...  

In 1988 and 1989 a muscadine vineyard at Tuskegeee, Alabama was treated by post plant soil solarization (PSS) (covering of moist soil around 'Carlos' muscadine plants (Vitis rotundifolia Michx.) with clear polyethylene plastic mulch to achieve high soil temperature for 30 and 75 days, respectively during PSS. Grape plants grown in solarized soils showed increases in growth response such as increased yield. Foliage of grape plants was evaluated for reaction to black rot incited by Guignardia bidwellii. A significant reduction of the foliage disease black rot was observed. The number of lesions per leaf, lesion size and percent leaves with lesions were significantly reduced by as much as 56% up to three years after solarization.

HortScience ◽  
1991 ◽  
Vol 26 (5) ◽  
pp. 486e-486
Author(s):  
C. Stevens ◽  
V. A. Khan ◽  
J. Y. Lu ◽  
M. K. Kabwe ◽  
Z. Haung ◽  
...  

In 1988 and 1989 a muscadine vineyard at Tuskegee, Alabama was treated by post soil solarization (PSS) (covering of moist soil around muscadine plants with clear polyethylene plastic mulch to achieve high soil temperature) for 30 and 75 days, respectively. The average soil temperature in 1989 of 50 and 35 C at 5cm depth for solarized and bare soil, respectively during PSS. The results showed no visible detrimental effect on `Carlos' muscadine (Vitis rotundifolia) from the increased heating of the soil. And the grape plants grown in solarized soils showed increases in growth response e.g. increased yield, revitalization of new softwood vines, vine weight/plant, etc. Uneven ripening of muscadine grapes was reduced on plants grown in PSS over bare soil as indicated by the increases in the percent soluble solids content of grape berries.


2017 ◽  
Vol 107 (2) ◽  
pp. 173-183 ◽  
Author(s):  
G. Onesti ◽  
E. González-Domínguez ◽  
V. Rossi

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.


Author(s):  
Liliana TOMOIAGA ◽  
Veronica Sanda CHEDEA

Guignardia bidwellii or black rot of vine is one of the most dangerous diseases that occur in vineyards in the center of Transylvania. The objective of this work was the tolerance testing of varieties and clones homologated at SCDVV Blaj to the Guignardia bidwellii attack. The behavior of vine varieties to the Guignardia bidwellii fungus attack was characterized by the analysis of the severity of the symptoms according to a scale in function of the attack degree (AD). The results obtained revealed the tolerance of the tested varieties: ‘Rubin’ (AD=0.13%), ‘Amurg’ (AD=0.25%), ‘Brumariu’ (AD=0.78%), ‘Radames’ (AD=0.96%) and ‘Blasius’ (AD=0.97%), a medium tolerance presented ‘Selena’ (AD=9.28%) variety and ‘Neuburger-10 Bl’ (AD=5.04%), ‘Iordana 9-1 Bl’ (AD=6.40%), ‘Riesling de Rhin 7-2’ (AD=7.2%), ‘Sauvignon-9 Bl’ (AD=9.28%), ‘Traminer roz-60 B’ clones (AD=17.5%) and susceptibility for ‘Astra’ variety (AD=25.56%) and ‘Riesling italian-3 Bl’ (AD=22.4%), ‘Pinot gris-34 Bl’ (AD=30.60%), ‘Feteasca regala-21 Bl’ (AD=31.50%), ‘Muscat Ottonel-12Bl’ (AD=35.30%), ‘Feteasca alba-29 Bl’ clones (AD=38.40%). The results obtained regarding the behavior of grapevine in the climatic conditions specific to the studied area for the 2016-2018 period, show that the lowest values of AD were registered for the ‘Rubin’ (AD=0.13%), ‘Amurg’ (AD=0.25%), ‘Brumariu’ (AD=0.78%), ‘Radames’ (AD=0.96%) and ‘Blasius’ (AD=0.97%) varieties homologated at SCDVV Blaj.


Plant Disease ◽  
1999 ◽  
Vol 83 (11) ◽  
pp. 1025-1032 ◽  
Author(s):  
J. X. Zhang ◽  
B. D. Bruton ◽  
M. E. Miller ◽  
T. Isakeit

Black rot of cantaloupe fruit, caused by Didymella bryoniae, can be severe when environmental conditions and fruit developmental stages are favorable for infection. Symptoms of black rot on cantaloupe fruit varied greatly depending on fruit age. The black rot phase was observed only on mature fruit. Inoculation of cantaloupe fruit at different developmental stages with five D. bryoniae isolates resulted in the greatest amount of decay on 10-day-old fruit compared with 20-, 30-, 40-, or 50-day-old fruit. There was no difference in lesion size among 20-, 30-, 40-, or 50-day-old fruit, although there was variation in lesion size among fungal isolates. Five fungal isolates all produced the greatest polygalacturonase (PG) activity in inoculated 10-day-old fruit compared with 20-, 30-, 40- or 50-day-old fruit. There was a positive correlation between lesion size and total fungal PG activity in decayed tissue. Using a representative D. bryoniae isolate (OK 963096), multiple PG isozymes were detected in both fungal shake culture and decayed fruit. Eleven PG isozymes (pI 4.7 to 7.9) were detected from fungal shake culture using pectin or polygalacturonic acid as the sole carbon source. Twelve PG isozymes (pI 4.7 to 8.7) were detected from decayed tissue of 10-day-old fruit, and 13 PG isozymes (pI 4.2 to 8.7) were observed from decayed tissue of 50-day-old fruit. The activity of D. bryoniae PG produced in vitro and in vivo was optimum at pH 5.0 and 5.5, respectively. The activity of the fungal PG produced in vitro exhibited primarily an endo-mode of action. In contrast, PG extracted from decayed tissue was predominately exo-PG. Thus, PG may play an important role in pathogenesis of D. bryoniae during cantaloupe fruit decay.


2011 ◽  
Author(s):  
Friederike Rex ◽  
Iris Fechter ◽  
Ludger Hausmann ◽  
Reinhard Töpfer

Plant Disease ◽  
2012 ◽  
Vol 96 (7) ◽  
pp. 1054-1059 ◽  
Author(s):  
Daniel Molitor ◽  
Cathleen Fruehauf ◽  
Ottmar Baus ◽  
Beate Berkelmann-Loehnertz

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.


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