Evaluation of combinations of chlorothalonil with azoxystrobin, harpin, and disease forecasting for control of downy mildew and gummy stem blight on melon

2007 ◽  
Vol 26 (2) ◽  
pp. 83-88 ◽  
Author(s):  
A.P. Keinath ◽  
G.J. Holmes ◽  
K.L. Everts ◽  
D.S. Egel ◽  
D.B. Langston
Keyword(s):  
Downy Mildew ◽  
Disease Forecasting ◽  
Stem Blight ◽  
Gummy Stem Blight

scholarly journals Reaction of melon genotypes to the gummy stem blight and the downy mildew

2009 ◽  
Vol 27 (2) ◽  
pp. 160-165 ◽  
Author(s):  
Gil R dos Santos ◽  
Manoel D de Castro Neto ◽  
Leandro N Ramos ◽  
Adalberto C Café-Filho ◽  
Ailton Reis ◽  
...  
Keyword(s):  
Downy Mildew ◽  
Cucumis Melo ◽  
Significant Variation ◽  
Natural Infection ◽  
Pseudoperonospora Cubensis ◽  
Didymella Bryoniae ◽  
Stem Blight ◽  
Gummy Stem Blight ◽  
Stem Infection ◽  
Leaf Infection

The gummy stem blight (Didymella bryoniae) and the downy mildew (Pseudoperonospora cubensis) are two foremost melon (Cucumis melo) diseases, considering their effects on yield and fruit quality. Despite the importance of such diseases, relatively few studies have been done so far on the identification of resistance sources to D. bryoniae and P. cubensis in Brazil. This work aimed at evaluating the resistance of commercial melon genotypes to the gummy stem blight and the downy mildew. Firstly, the most aggressive and representative D. bryoniae isolate was selected. Subsequently, the resistance of 86 melon genotypes to stem infection was studied upon greenhouse conditions by inoculating with the previously selected isolate. Afterwards, the resistance to mildew and leaf infection by D. bryoniae of 28 melon genotypes was evaluated in the field, under natural infection. In the greenhouse, all 86 melon genotypes were infected and showed stem infection symptoms caused by D. bryoniae four days after inoculation. Nevertheless, a significant variation on the resistance levels of the melon genotypes was found. Under field conditions and natural inoculation, genotypes Taslaki and Sary Juliabi were the most susceptible to leaf infection by D. bryoniae, significantly differing from the other genotypes. The lowest levels of susceptibility were identified in genotypes Perlita Busle S1, Valenciano Elíptico, Glaver, MR1, and 2526. All genotypes were susceptible to the downy mildew, albeit differing in susceptibility levels.

Factors Promoting Pycnidia Production of Didymella bryoniae, the Causal of Gummy Stem Blight in Cucurbits

2017 ◽  
Vol 45 (1) ◽  
pp. 173-187
Author(s):  
Abdel-Fattah El-Wakil ◽  
Amal Khalil ◽  
Ibrahim El -Abbasi
Keyword(s):  
Didymella Bryoniae ◽  
Stem Blight ◽  
Gummy Stem Blight

scholarly journals QTL Mapping for Gummy Stem Blight Resistance in Watermelon (Citrullus spp.)

Plants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 500
Author(s):  
Eun Su Lee ◽  
Do-Sun Kim ◽  
Sang Gyu Kim ◽  
Yun-Chan Huh ◽  
Chang-Gi Back ◽  
...  
Keyword(s):  
Chromosome 8 ◽  
Chromosome 6 ◽  
Potential Candidate ◽  
Stem Blight ◽  
Gummy Stem Blight ◽  
F2 Population ◽  
Leaf Lesion ◽  
Phenotypic Variations ◽  
A Minor ◽  
Selection Of

Watermelon (Citrulluslanatus) is an economically important fruit crop worldwide. Gummy stem blight (GSB) is one of the most damaging diseases encountered during watermelon cultivation. In the present study, we identified quantitative trait loci (QTLs) associated with GSB resistance in an F2 population derived from a cross between maternal-susceptible line ‘920533’ (C. lanatus) and the paternal-resistant line ‘PI 189225’ (C. amarus). The resistance of 178 F2 plants was assessed by two different evaluation methods, including leaf lesion (LL) and stem blight (SB). To analyze the QTLs associated with GSB resistance, a linkage map was constructed covering a total genetic distance of 1070.2 cM. QTL analysis detected three QTLs associated with GSB resistance on chromosome 8 and 6. Among them, two QTLs, qLL8.1 and qSB8.1 on chromosome 8 identified as major QTLs, explaining 10.5 and 10.0% of the phenotypic variations localizing at same area and sharing the same top markers for both LL and SB traits, respectively. A minor QTL, qSB6.1, explains 9.7% of phenotypic variations detected on chromosome 6 only for the SB trait. High-throughput markers were developed and validated for the selection of resistant QTLs using watermelon accessions, and commercial cultivars. Four potential candidate genes were predicted associated with GSB resistance based on the physical location of flanking markers on chromosome 8. These findings will be helpful for the development of watermelon cultivars resistant to GSB.

Temporal and spatial dynamics of watermelon gummy stem blight epidemics

2010 ◽  
Vol 128 (4) ◽  
pp. 473-482 ◽  
Author(s):  
Adalberto C. Café-Filho ◽  
Gil R. Santos ◽  
Francisco F. Laranjeira
Keyword(s):  
Spatial Dynamics ◽  
Stem Blight ◽  
Gummy Stem Blight ◽  
Temporal And Spatial

Boscalid Insensitivity Documented in Didymella bryoniae Isolated from Watermelon in Florida and North Carolina

2012 ◽  
Vol 13 (1) ◽  
pp. 42
Author(s):  
Katherine L. Stevenson ◽  
Anthony P. Keinath ◽  
Anna Thomas ◽  
David B. Langston ◽  
Pamela D. Roberts ◽  
...  
Keyword(s):  
North Carolina ◽  
South Carolina ◽  
High Frequency ◽  
In Vitro Assays ◽  
Didymella Bryoniae ◽  
Triazole Fungicides ◽  
Stem Blight ◽  
Gummy Stem Blight ◽  
Commercial Mixture

The fungicide Pristine, a commercial mixture of pyraclostrobin and boscalid, has been used widely on watermelon and other cucurbits to control gummy stem blight, caused by the fungus Didymella bryoniae. Since 2007, isolates of D. bryoniae insensitive to boscalid have been found in Georgia, Indiana, and South Carolina. Most isolates of D. bryoniae obtained in 2009 and 2010 from diseased watermelon leaves collected in several counties in Florida and North Carolina were found to be insensitive to boscalid using in vitro assays. Gummy stem blight would not be effectively managed with Pristine in any of the counties where samples were collected due to the high frequency of insensitivity to boscalid. Fortunately growers can instead use several triazole fungicides registered for use on cucurbits since 2009. Accepted for publication 30 March 2012. Published 18 May 2012.

Gummy stem blight resistance of cucumbers (Cucumis sativus L.)

Euphytica ◽  
1978 ◽  
Vol 27 (3) ◽  
pp. 861-864 ◽  
Author(s):  
Q. P. Van Der Meer ◽  
J. L. Van Bennekom ◽  
A. C. Van Der Giessen
Keyword(s):  
Cucumis Sativus ◽  
Blight Resistance ◽  
Cucumis Sativus L ◽  
Stem Blight ◽  
Gummy Stem Blight

scholarly journals Identification and Characterization of the Causal Organism of Gummy Stem Blight in the Muskmelon (Cucumis meloL.)

Mycobiology ◽  
2010 ◽  
Vol 38 (3) ◽  
pp. 166 ◽  
Author(s):  
In Young Choi ◽  
Jang Nam Choi ◽  
Dong Chil Choi ◽  
Praveen Kumar Sharma ◽  
Wang Hyu Lee
Keyword(s):  
Causal Organism ◽  
Stem Blight ◽  
Gummy Stem Blight ◽  
Identification And Characterization

scholarly journals Effect of nitrogen doses on disease severity and watermelon yield

2009 ◽  
Vol 27 (3) ◽  
pp. 330-334 ◽  
Author(s):  
Gil R dos Santos ◽  
Manoel D de Castro Neto ◽  
Hudson SM de Almeida ◽  
Leandro N Ramos ◽  
Renato A Sarmento ◽  
...  
Keyword(s):  
Disease Severity ◽  
Nitrogen Fertilization ◽  
Citrullus Lanatus ◽  
Fruit Yield ◽  
Control Treatment ◽  
Average Weight ◽  
Stem Blight ◽  
Gummy Stem Blight ◽  
Yield And Quality ◽  
Severity Levels

Nitrogen fertilization is an important step for watermelon (Citrullus lanatus) production due to its influence over yield, fruit quality, and disease severity. Currently, the gummy stem blight (Didymella bryoniae) and the downy mildew (Pseudoperonospora cubensis) can be taken as the most important watermelon diseases, since they impose severe impairment to the crop. Furthermore, studies focusing on plant responses to nitrogen fertilization regarding fruit yield and quality, and disease resistance are rare. Hence, the present study aimed at evaluating the effect of nitrogen doses on fruit yield and quality, and on disease prevalence in watermelon. Two experiments were carried out at the Universidade Federal de Tocantins, employing sprinkler irrigation, in an area previously used to grow watermelon. The experimental design was blocks at random, with five treatments (N doses, applied twice as side-dressing, in kg ha-1, as follows: T1= control treatment without N, T2= 20, T3= 40, T4= 80, and T5= 120), and four replications. Urea (45% N) was used as the N source. In the first assay, the highest fruit yield and average weight were observed when 40 kg ha-1 of N were applied. The highest severity of the gummy stem blight was observed when the highest nitrogen doses were applied (80 and 120 kg ha-1). In the second assay, the highest severity levels of the gummy stem blight, as well as of mildew, were observed again when N doses were the highest (80 and 120 kg ha-1). The lowest severity levels for both diseases were observed in the control treatment.

scholarly journals Effect of Fungicide Applications Scheduled to Control Gummy Stem Blight on Yield and Quality of Watermelon Fruit

Plant Disease ◽  
2001 ◽  
Vol 85 (1) ◽  
pp. 53-58 ◽  
Author(s):  
Anthony P. Keinath
Keyword(s):  
Disease Severity ◽  
Fruit Weight ◽  
Fruit Rot ◽  
Soluble Solids ◽  
Black Rot ◽  
Soluble Solids Content ◽  
Stem Blight ◽  
Gummy Stem Blight ◽  
Yield And Quality ◽  
Solids Content

Yield and quality reductions in watermelon infected with Didymella bryoniae may be attributed to reduced number or weight of fruit, sunburned fruit, fruit rot, or low sugar content due to gummy stem blight on foliage and black rot on fruit. Number, weight, soluble solids content, and external appearance of fruit were determined in four experiments conducted in fall 1996 and 1997 and spring 1997 and 1998. Severity of gummy stem blight was varied by applying no fungicide, mancozeb, or chlorothalonil according to different schedules. In the fall, when disease severity was high, total fruit weight, percent marketable fruit, and soluble solids content were lower and percent fruit with black rot was higher in nonsprayed than in sprayed treatments. Fungicide applications did not affect total fruit weight, soluble solids content, or black rot in the spring, when disease severity was moderate to low. Percent sunburned fruit was greater in treatments sprayed every 14 days than in those sprayed weekly. In fall experiments, the number of healthy, unblemished fruit increased linearly as the number of fungicide applications was increased from zero to nine per season. Yield losses in watermelon to gummy stem blight and black rot resulted primarily from a reduction in total fruit weight and an increase in number of diseased and sunburned fruit.

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