scholarly journals Severe Outbreaks of Bunch Rots Caused by Rhizopus stolonifer and Aspergillus niger on Table Grapes in Chile

Plant Disease ◽  
2002 ◽  
Vol 86 (7) ◽  
pp. 815-815 ◽  
Author(s):  
B. A. Latorre ◽  
S. C. Viertel ◽  
I. Spadaro
Keyword(s):  
Aspergillus Niger ◽  
Cultural Practices ◽  
Weather Conditions ◽  
Soluble Solids ◽  
Vitis Vinifera L ◽  
Rhizopus Stolonifer ◽  
Thompson Seedless ◽  
Table Grapes ◽  
Hypodermic Syringe ◽  
Black Mold

Severe outbreaks of bunch rots (BR) have occurred recently during harvest of table grapes (Vitis vinifera L.) in Chile. Previously, BR was almost exclusively associated with Botrytis cinerea Pers.:Fr. (2,3); however, in 2000 to 2002, BR symptoms were associated with black molds and possibly nonfilamentous yeasts and bacteria. Cvs. Thompson Seedless, Flame Seedless, Ruby Seedless, and Red Globe were severely affected. Symptoms start at the pedicels as soft, watery rots that partially or completely decay infected berries. Longitudinal cracks are produced, a black mold usually develops along the crack fissures, and the skin of the berry turns light gray. Isolations on potato dextrose agar acidified with 1 N lactic acid (APDA) at 0.5 ml/liter, consistently yielded Rhizopus stolonifer (Ehrenb. ex Fr.) Vuillemin and Aspergillus niger Tiegh. R. stolonifer on APDA produced a white-to-gray aerial and nonseptate mycelium, black and globose sporangia with an elliptical collumela, one-celled, globose to oval, striated, almost hyaline sporangiospores, rhizoids, and stolons. A. niger produced septate mycelium. Single-celled, black, rough walled, globose conidia developed on short chains on the second phialides at the tip of globose, upright conidiophores. Mature (soluble solids >16%) detached berries of cv. Thompson Seedless were inoculated with sporangiospores (≈107 spores per ml) of R. stolonifer isolates RS6, RS52, RS73, and RS79 and conidia (≈108 conidia per ml) of A. niger isolates AN12, AN69, and AN75. When berries were aseptically punctured with a sterile hypodermic syringe prior to inoculation, 60 to 86.7% and 42.5 to 100% of berries were infected with R. stolonifer and A. niger, respectively, and both developed BR symptoms (significantly different from control berries) after 48 h in humid chambers at 23°C. Injuries were needed for infection since no infection or only 23.3% of noninjured berries were infected with R. stolonifer and A. niger, respectively. For both pathogens, there was a significant (P < 0.043) interaction between isolates and the presence or absence of injuries. Both pathogens were successfully reisolated on APDA. Fungicide sensitivity tests were performed on detached cv. Thompson Seedless berries challenged by placing an ≈6 μl-drop of inoculum suspension (106 or 107 spores per ml of R. stolonifer isolate RS52 and A. niger isolate AN12, respectively) on injured berries. Pyraclostrobin (0.067 mg/ml) mixed with nicobifen at 0.134 mg/ml (BAS 516 01 F at 0.201 mg a.i./ml, BASF) and copper oxide at 1.2 mg/ml (Cuprodul 60 WP, Quimetal Chile) significantly (P < 0.01) inhibited infection (100% control) by R. stolonifer and A. niger. R. stolonifer was completely controlled by dicloran at 1.88 mg/ml (Botran 75 WP) and partially controlled by captan at 1.6 mg/ml (Captan 80 WP), but A. niger was not controlled by either fungicide. To our knowledge this is the first report of R. stolonifer causing BR of table grape in Chile (4). The severe outbreaks may be associated with warm weather conditions during harvest and injuries caused by birds, insects, or cultural practices. Infection caused by R. stolonifer or A. niger may be followed by sour rot organisms (yeasts or bacteria), as has been suggested elsewhere (1,2). References: (1) E. Gravot et al. Phytoma 543:36, 2001. (2) W. B. Hewitt Page 26 in: Compendium of Grape Diseases, American Phytopathological Society, St. Paul, MN, 1994. (3) B. A. Latorre and G. Vásquez. Aconex (Chile) 52:16, 1996. (4) F. Mujica and C. Vergara. Flora Fungosa Chilena. Universidad de Chile, Facultad de Agronomiacute;a, Santiago, Chile, 1980.

scholarly journals Grapevine Variety and Number of Canes Affect Dry-on-Vine (DOV) Raisin Production on an Overhead Arbor Trellis

Horticulturae ◽  
2021 ◽  
Vol 7 (10) ◽  
pp. 356
Author(s):  
Matthew W. Fidelibus
Keyword(s):  
The Other ◽  
Soluble Solids ◽  
Vitis Vinifera L ◽  
Mature Fruit ◽  
Thompson Seedless ◽  
High Productivity ◽  
Grapevine Variety ◽  
Industry Standards ◽  
Main Plot ◽  
Grape Varieties

Making raisins (dried grapes) is a laborious process and grape growers around the world are increasingly interested in adopting mechanized methods, especially dry-on-vine (DOV). The DOV method entails severing canes bearing mature fruit, causing them to DOV, after which they may be harvested by machine. The overhead arbor is an important DOV raisin trellis system, but basic agronomic performance of raisin varieties on that system are scant. Therefore, a three-year experiment was conducted to compare the performance of several raisin grape varieties (Vitis vinifera L.), on an overhead arbor trellis, for production of DOV raisins. Grapevine variety, ‘DOVine’, ‘Fiesta’, ‘Selma Pete’, or ‘Thompson Seedless’, was the main-plot factor, and number of canes, six or eight, was the sub-plot. ‘Fiesta’ produced the highest yields, averaging about 12.24 Mg/ha raisins. However, ‘Fiesta’ generally had the lowest soluble solids and among the lowest raisin grades. The later ripening of ‘Fiesta’ fruit delayed harvest pruning to initiate fruit drying compared to the other varieties. Therefore, its raisins did not dry sufficiently to meet industry standards. ‘Selma Pete’, ‘DOVine’, and ‘Thompson Seedless’ had similar yields, generally about 20% less than ‘Fiesta’, but ‘Selma Pete’ produced fruit that were the largest in size, with the highest soluble solids, and that produced raisins of the highest grades, compared to the other varieties. Vines pruned to eight canes produced higher yields without sacrificing raisin quality. In conclusion, ‘Fiesta’ was notable for its high productivity, and ‘Selma Pete’ for its earliness and high quality, and both varieties had sufficient capacity to carry eight 15-node canes.

scholarly journals Evaluation of Onion Cultivars for Resistance to Aspergillus niger, the Causal Agent of Black Mold

2002 ◽  
Vol 127 (4) ◽  
pp. 697-702 ◽  
Author(s):  
Swee-Suak Ko ◽  
Jenn-Wen Huang ◽  
Jaw-Fen Wang ◽  
Subramanyam Shanmugasundaram ◽  
Woo-Nang Chang
Keyword(s):  
Aspergillus Niger ◽  
Incubation Temperature ◽  
Storage Conditions ◽  
Lesion Size ◽  
Soluble Solids ◽  
Postharvest Disease ◽  
Lesion Diameter ◽  
Screening Protocol ◽  
Black Mold ◽  
Incubation Temperatures

Black mold (BM), caused by Aspergillus niger Tiegh., is a common onion (Allium cepa L.) postharvest disease under hot and humid storage conditions. This study aimed to develop a BM screening protocol, to evaluate onion cultivars for resistance. The effects of pathogen isolate, inoculum density, incubation temperature, and inoculation method on severity of BM were investigated in designing the screening protocol. Variation in virulence was observed and two highly virulent subcultures, An4-2 and An39-3, were selected for study. Disease severity, both in lesion size and sporulation degree, increased with higher inoculum densities and incubation temperatures. In contrast, small lesions and no sporulation were observed when onion scales were inoculated with 1 × 104 spores/mL or incubated at temperatures lower than 20 °C. Inoculation of onion scales or entire bulbs were compared and scale inoculation correlated better with BM incidence in storage. The procedure for BM screening protocol included: wound inoculation of onion slices with 40 μL inoculum suspension of 1 × 105 spores/mL, incubation at 25 °C with 12 hour photoperiod, and rating lesion diameter and sporulation 4 days after inoculation. Using this screening protocol, 42 onion cultivars were evaluated and cultivars with better storability such as `Red Pinoy', `Serrana', `Dehydrator No.3', and `Moonlight' were tolerant to A. niger. These cultivars showed small lesions and no sporulation during screening. On the other hand, cultivars with poor storability like `Texas Early Grano 502', `Granex 429', and `Explorer' exhibited larger lesions with profuse sporulation. Lesion diameter caused by the scale inoculation correlated significantly with bulb storage loss (r = 0.51, P < 0.01) as well as with bulb dry matter (r = -0.48, P < 0.01) and total soluble solids (r = - 0.51, P < 0.01). The screening protocol and tolerant materials are now successfully used in the Asian Vegetable Research and Development Center onion breeding program for resistance to black mold.

scholarly journals Effects of irrigation and shoot thinning on the size and phenolics content of developing grape berries (Vitis vinifera L. cv. Tempranillo)

2020 ◽  
Vol 18 (2) ◽  
pp. e0803
Author(s):  
María E. Molero-de-Ávila ◽  
María V. Alarcón ◽  
Daniel Moreno ◽  
Luis A. Mancha ◽  
David Uriarte ◽  
...  
Keyword(s):  
Cultural Practices ◽  
Total Phenolics ◽  
Irrigation Treatment ◽  
Weather Conditions ◽  
Stage Ii ◽  
Vitis Vinifera L ◽  
Grape Berries ◽  
Berry Size ◽  
Phenolics Content ◽  
Maximum Temperatures

 Aim of study: The concentration of phenolics in the grape berries can be influenced by cultural practices such as irrigation or thinning. The main objective of the present study was to evaluate the effect of combinations of these practices on grape size and phenolics content. Area of study: The trial was carried out in an experimental cv. Tempranillo vineyard located in Extremadura, Spain. Material and methods: Two irrigation regimes were considered: rainfed vines (non-irrigated, NIr), and 100% ETc irrigated vines (Ir). For each irrigation treatment, two cropping levels were studied: low shoot-thinning (LT) vs high shoot-thinning (HT) implemented in winter and spring, respectively. Berry weight, and total phenolics, proanthocyanidin, and anthocyanin concentrations were determined at eight stages of berry development in three consecutive years (2014, 2015, and 2016). Main results: Specific weather conditions of each year affected phenolics accumulation differently. In 2014, where maximum temperatures were low and an important rainfall occurred at Stage II, both the NIr-LT and NIr-HT treatments led to the greatest concentrations of total phenolics, proanthocyanidins, and anthocyanins. In 2015, where a little rainfall was registered at Stage II, the berries from the NIr-HT and Ir-HT treatments accumulated the greatest total phenolics and proanthocyanidin contents, but the NIr-LT and NIr-HT treatments led to the greatest accumulation of anthocyanins. Finally, in 2016, where high maximum temperatures and scarce rainfall were registered, the Ir-LT and Ir-HT treatments presented the greatest concentrations of total phenolics, proanthocyanidins, and anthocyanins. Research highlights: A significant effect of irrigation and thinning was observed on berry size and phenolic content, as well as year × thinning interaction.

scholarly journals Crop Load Effects on Irrigated and Non-irrigated Vitis vinifera L. cv. Thompson Seedless

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 779G-780
Author(s):  
Larry E. Williams
Keyword(s):  
Leaf Tissue ◽  
Growing Season ◽  
Experimental Period ◽  
Soluble Solids ◽  
Vitis Vinifera L ◽  
Thompson Seedless ◽  
Gas Exchange Parameters ◽  
Fruit Removal ◽  
Load Effects ◽  
Exchange Parameters

A study was conducted to determine the effects of crop removal on gas exchange parameters of `Thompson Seedless' grapevines grown in the San Joaquin Valley of California. Vines were either irrigated at full ET or not irrigated throughout the growing season. Clusters were removed subsequent to veraison, when the fruit soluble solids were ≈15° Brix. Reductions in leaf net CO2 assimilation rate (A) were measured within 1 day of fruit removal for both irrigation treatments and remained such until the end of the experiment. The greatest reduction in A due to crop removal on a diurnal basis was with the non-irrigated vines between 0800 and 1000 hr. The reduction in A subsequent to crop removal was not the result of an accumulation of either starch or sugars in leaf tissue. The greater reduction in A of non-irrigated vines after fruit removal may have been due to the lack of strong, alternate sinks as vegetative growth was minimal due to water stress during the experimental period.

scholarly journals Anthocyanin Accumulation and Color Development of ‘Benitaka’ Table Grape Subjected to Exogenous Abscisic Acid Application at Different Timings of Ripening

Agronomy ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 164 ◽  
Author(s):  
Muhammad Shahab ◽  
Sergio Roberto ◽  
Saeed Ahmed ◽  
Ronan Colombo ◽  
João Silvestre ◽  
...  
Keyword(s):  
Abscisic Acid ◽  
Skin Color ◽  
Color Index ◽  
Chemical Properties ◽  
Cropping System ◽  
Soluble Solids ◽  
Vitis Vinifera L ◽  
Anthocyanin Accumulation ◽  
Table Grapes ◽  
Index Development

In colored table grapes, the anthocyanin contents are inhibited by the high temperature during ripening and berries suffer a lack of skin color, thus affecting their market value. In order to overcome this issue, a research study was planned to evaluate the influence of (S)-cis-abscisic acid (S-ABA) on rates of anthocyanin accumulation in table grapes when applied at different timings of ripening, and to quantify the gradual increase of berry color. The study was conducted in a commercial vineyard of ‘Benitaka’ table grapes (Vitis vinifera L.), grown under double annual cropping system in a subtropical area. The trials were carried out during two consecutive seasons (i.e., summer season of 2015 and off-season of 2016). The treatments used for the experiments contained 400 mg L−1 S-ABA applied at different timings of veraison (the onset of ripening), as follows: control (with no application); at pre-veraison (PRV); at veraison (V); and at post-veraison (POV). For all S-ABA treatments, a second application was performed 10 days after the first application. Berries were analyzed for weekly and daily anthocyanin accumulations, weekly and daily color index development (CIRG), total soluble solids (TSS) content, titratable acidity (TA), and maturation index (TSS/TA). Grapes subjected to exogenous application of S-ABA at any time of veraison, especially at PRV or at V, significantly increased the anthocyanin accumulation as well as berry color index development. Other chemical properties of grapes (i.e., TSS, TA, and TSS/TA evolution) were not affected by the use of S-ABA and followed a predictable pattern in relation to days of berries ripening.

scholarly journals Die invloed van haelnette op die prestasie van tafeldruiwe Vitis vinifera (L.) in die somer- reëngebied

1995 ◽  
Vol 14 (3) ◽  
pp. 85-91
Author(s):  
J. H. Avenant
Keyword(s):  
Acid Concentration ◽  
Titratable Acidity ◽  
Soluble Solids ◽  
Sugar Concentration ◽  
Vitis Vinifera L ◽  
Mass Yield ◽  
Direct Sunlight ◽  
Table Grapes ◽  
Long Term Effect

The long term effect of black hail netting (20% shading) on budding percentage, but fertility, cane mass, yield, bunch mass, berry mass and berry cracking as well as sugar concentration (total soluble solids), acid concentration (titratable acidity) and pH of the berry juice of table grapes (cultivars Pirobella, Bien Donne, Ronelle and Italia) was evaluated. Budding percentage and bud fertility were significantly reduced by hail netting. Reproductive growth in terms of yield and bunch mass seemed to be higher under hail netting compared to direct sunlight, while berry mass was not affected. Berry cracking tended to decrease under hail netting. Berry sugar concentration and pH decreased significantly under hail netting, while the acid concentration increased.

scholarly journals Vapor Phase Hydrogen Peroxide Inhibits Postharvest Decay of Table Grapes

HortScience ◽  
1991 ◽  
Vol 26 (12) ◽  
pp. 1512-1514 ◽  
Author(s):  
Charles F. Forney ◽  
Roger E. Rij ◽  
Ricardo Denis-Arrue ◽  
Joseph L. Smilanick
Keyword(s):  
Hydrogen Peroxide ◽  
Botrytis Cinerea ◽  
Vapor Phase ◽  
Soluble Solids ◽  
Soluble Solids Content ◽  
Thompson Seedless ◽  
Table Grapes ◽  
Polyethylene Bags ◽  
Solids Content ◽  
Potential Use

The potential use of vapor phase hydrogen peroxide (VPHP) to prevent decay caused by Botrytis cinerea Pers. ex Fr. in table grapes (Vitis vinifera L.) was investigated. `Thompson Seedless' and `Red Globe' grapes, inoculated with Botrytis cinerea spores, were placed in polyethylene bags and flushed for 10 minutes with VPHP generated from a 30% to 35% solution of liquid hydrogen peroxide at 40C. Immediately after treatment, bags were sealed and held at 10C. Vapor phase hydrogen peroxide significantly reduced the number of terminable Botrytis spores on grapes. The number of terminable spores on `Thompson Seedless' and `Red Globe' grapes had been reduced 81% and 62%, respectively, 24 hours following treatment. The incidence of decay on inoculated `Thompson Seedless' and `Red Globe' grapes was reduced 33% and 16%, respectively, after 8 days of storage at 10C compared with control fruit. Vapor phase hydrogen peroxide reduced the decay of noninoculated `Thompson Seedless' and `Red Globe' grapes 73% and 28%, respectively, after 12 days of storage at 10C. Treatment with VPHP did not affect grape color or soluble solids content.

scholarly journals 791 PB 033 INFLUENCE OF GIBBERELLIC ACID ON SIZING OF THOMPSON SEEDLESS TABLE GRAPES IN SOUTHWEST ARIZONA

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 546d-546 ◽  
Author(s):  
Marvin D. Butler ◽  
Robert E. Rush
Keyword(s):  
Gibberellic Acid ◽  
Soluble Solids ◽  
Fresh Market ◽  
Thompson Seedless ◽  
Table Grapes ◽  
Yield And Quality ◽  
Berry Weight ◽  
Berry Size ◽  
Desert Southwest ◽  
Data Yield

Early berry maturity with adequate size and sugar is a high priority for table grape producers in the desert southwest trying to capture the early fresh market, when prices are historically at their highest. Application of gibberellic acid is used, in combination with girdling to increase berry size. Research was conducted at Valley Grapes near Dateland, AZ on 1.5 hectare unreplicated plots in 1987 and 1988, and 0.2 hectare plots replicated four times in 1989 and 1990. The influence of 120g/h, 160gh and 200g/h of gibberellic acid, applied two to three times in various combinations, was evaluated on Thompson seedless grapes. Preharvest samples provided berry weight and soluble solids data. Yield and quality were determined from the number and grade of 10 kilogram boxes harvested for each pick. Berry weight tended to increase with increased rates of gibberellic acid while yield and quality were highest for more moderate rates. Three applications generally out-performed two applications with the same, or similar, total amount of gibberellic acid.

scholarly journals Effects of Several Preharvest Canopy Applications on Yield and Quality of Table Grapes (Vitis vinifera L.) Cv. Crimson Seedless

Plants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 906
Author(s):  
Despoina G. Petoumenou ◽  
Vasileios-Emmanouil Patris
Keyword(s):  
Fruit Quality ◽  
Abiotic Stress Tolerance ◽  
Table Grape ◽  
Viable Alternative ◽  
Soluble Solids ◽  
Control Treatment ◽  
Anthocyanin Synthesis ◽  
Vitis Vinifera L ◽  
Grape Variety ◽  
Table Grapes

Modern viticultural areas are being confronted with the negative impacts of global warming on yield and fruit composition, with especially adverse effects on anthocyanin synthesis. Novel and sustainable tools, such as biostimulants, may represent a viable alternative to traditional cultural practices, thus promoting eco-friendly strategies to enhance the yield, fruit quality and abiotic stress tolerance of grapevines. ‘Crimson Seedless’ is a late-season red table grape variety, and due to climatic warming, its berries are frequently failing to acquire the commercially acceptable red color. Canopy applications of different biostimulants, namely, Kelpak®, Sunred®, Cytolan®, LalVigne™ Mature as well as Ethrel® Top, were tested on grapevine cv. Crimson Seedless grown under semi-arid Mediterranean conditions in order to evaluate their effects on yield and fruit quality. Some of the products were sprayed in canopies at labeled doses, and some were applied at doses reported in other studies. For the control treatment, canopies were sprayed with water. Sampling started at veraison and was repeated at 10-day intervals to measure the evolution of berry weight, length and diameter, as well as the total soluble solids and titratable acidity of the juice. The grapes were harvested when the berries of one of the treatments attained the commercially acceptable color. The greatest improvements in the red berry color were achieved with Sunred® (at a dose of 4 L ha−1) and Ethrel® Top (250 ppm plus glycerol at 1%), each applied at veraison and 10 days later. The different applications had varying effects on productivity and qualitative parameters. Only Sunred® improved the accumulation of anthocyanin and the overall acceptability of table grapes by consumers. The obtained results clearly demonstrate that applying Sunred® can improve the yield and qualitative parameters of the red table grape variety ‘Crimson Seedless’, indicating that this biostimulant could be a viable alternative to the most widely used plant growth regulator, ethephon.

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