scholarly journals Effect of Incorporation of Brassica spp. Residues on Population Densities of Soilborne Microorganisms and on Damping-off and Fusarium Wilt of Watermelon

Plant Disease ◽  
2008 ◽  
Vol 92 (2) ◽  
pp. 287-294 ◽  
Author(s):  
Samuel M. C. Njoroge ◽  
Melissa B. Riley ◽  
Anthony P. Keinath
Keyword(s):  
South Carolina ◽  
Fusarium Wilt ◽  
Methyl Bromide ◽  
Field Experiments ◽  
Citrullus Lanatus ◽  
Total Concentration ◽  
Management Tool ◽  
Damping Off ◽  
Amended Soils ◽  
Brassica Spp

Incorporating Brassica spp. residue to reduce populations of soilborne fungi and manage damping-off and Fusarium wilt of watermelon (Citrullus lanatus var. lanatus) was studied in two field experiments. Treatments included incorporating flowering Brassica napus cv. Dwarf Essex canola or B. juncea cv. Cutlass mustard and laying black polyethylene mulch at incorporation or 1 month after incorporation, methyl bromide, and a nontreated control. In both years, glucosinolates were identified and quantified in the shoots and roots of the flowering plants. In both years, the total concentration of glucosinolates incorporated per square meter was significantly higher for B. juncea than for B. napus. Isothiocyanates were inconsistently detected in the amended soils and none were detected more than 12 days postincorporation. After incorporation in 2004 and 2005, amended plots had higher populations of Fusarium oxysporum and Pythium spp. than the methyl bromide treatment, and in some treatments, populations were higher than in the control. Fluorescent Pseudomonas spp. were not suppressed in amended soils, and their populations were significantly higher in some amended treatments than those in methyl bromide-treated soils or nontreated control soils. Incidence of damping-off and severity of Fusarium wilt on seedless watermelon cv. Tri-X 313, which is susceptible to Fusarium wilt, were not consistently lower in brassica-amended soils or methyl bromide-treated plots than in nontreated control plots. Therefore, under spring conditions and methods used in this study, neither biofumigation nor methyl bromide fumigation in coastal South Carolina was an effective disease management tool for two soilborne pathogens of watermelon.

Effects of Host Resistance and Inoculum Density on the Suppression of Fusarium Wilt of Watermelon Induced by Hairy Vetch

Plant Disease ◽  
2007 ◽  
Vol 91 (1) ◽  
pp. 92-96 ◽  
Author(s):  
X. G. Zhou ◽  
K. L. Everts
Keyword(s):  
Fusarium Wilt ◽  
Citrullus Lanatus ◽  
Inoculum Density ◽  
Disease Suppression ◽  
Management Tool ◽  
Infested Soil ◽  
Hairy Vetch ◽  
Inoculum Level ◽  
Resistance Level ◽  
Bacterial Populations

Hairy vetch (Vicia villosa) used as a soil amendment is a newly described potential management tool for the suppression of Fusarium wilt of watermelon (Citrullus lanatus). However, the effect of inoculum density and the level of resistance in the host on the level of suppression are not understood. In this study, hairy vetch-induced wilt suppression was evaluated in the greenhouse on 12 watermelon cultivars with different levels of wilt resistance and in 16 naturally infested soil samples collected from commercial watermelon fields. Wilt suppression occurred in all but two cultivars and with the trend that suppression increased as the level of resistance in cultivars increased. Fusarium wilt suppression was 22, 53, and 63% in hairy vetch-amended soil compared with nonamended soil on cultivars ranked as susceptible, moderately resistant, and highly resistant, respectively. Suppression also occurred in nine of the soils that contained populations of Fusarium oxysporum f. sp. niveum below 1,100 CFU/g of soil. However, at this level or higher, significant wilt suppression was not observed. The magnitude of disease suppression decreased with the increase of inoculum in the soils. The induced wilt suppression appeared to be correlated with an increase in bacterial populations in soil. Hairy vetch-induced suppression to Fusarium wilt in watermelon is dependent on the resistance level of cultivars and is overcome by high inoculum level of F. oxysporum f. sp. niveum in soil.

Sensitivity of Fusarium oxysporum f. sp. niveum to Prothioconazole and Pydiflumetofen In Vitro and Efficacy for Fusarium Wilt Management in Watermelon

2020 ◽  
Vol 21 (1) ◽  
pp. 13-18 ◽  
Author(s):  
Nathan F. Miller ◽  
Jeffrey R. Standish ◽  
Lina M. Quesada-Ocampo
Keyword(s):  
North Carolina ◽  
Fusarium Oxysporum ◽  
Fusarium Wilt ◽  
Field Experiments ◽  
Foliar Application ◽  
Citrullus Lanatus ◽  
Disease Incidence ◽  
Application Rate ◽  
Current Evidence ◽  
Progress Curve

Field experiments were conducted in 2015 and 2016 to determine the effects of drench or drench-plus-foliar applications of prothioconazole and pydiflumetofen on Fusarium wilt (caused by Fusarium oxysporum f. sp. niveum; FON) of watermelon (Citrullus lanatus var. lanatus). In both years, all fungicide treatments reduced final disease incidence, final severity, and area under the disease progress curve, regardless of application rate or method. Yield data were collected in 2016, and both number and weight of marketable fruit were greatest in plots treated with pydiflumetofen as a drench-plus-foliar application at either application rate. Additional experiments were conducted to characterize sensitivity distributions of 48 isolates of FON from North Carolina to prothioconazole and pydiflumetofen. Mean prothioconazole EC50 values ranged from 0.10 to 0.55 µg/ml, and mean pydiflumetofen EC50 values ranged from 0.34 to 1.88 µg/ml. The results presented here validate pydiflumetofen as an effective management option for Fusarium wilt of watermelon, confirm previously observed efficacy of prothioconazole, and provide current evidence of pathogen sensitivity to these fungicides in North Carolina.

scholarly journals Watermelon Seedling Growth, Fruit Yield, and Quality following Pretransplant Nutritional Conditioning

HortScience ◽  
1994 ◽  
Vol 29 (11) ◽  
pp. 1264-1268 ◽  
Author(s):  
Jonathan R. Schultheis ◽  
Robert J. Dufault
Keyword(s):  
South Carolina ◽  
Leaf Area ◽  
Seedling Growth ◽  
Field Experiments ◽  
Citrullus Lanatus ◽  
Hollow Heart ◽  
Staminate Flower ◽  
Calcium Nitrate ◽  
Fruit Yield ◽  
Yield And Quality

Pretransplant nutritional conditioning (PNC) of transplants during greenhouse production may improve recovery from transplanting stress and enhance earliness and yield of watermelon [Citrullus lanatus (Thumb.) Matsum. & Nakai]. Two greenhouse experiments (Expts. 1 and 2) and field experiments in South Carolina and North Carolina (Expt. 3) were conducted to evaluate N and P PNC effects on watermelon seedling growth and their effects on fruit yield and quality. `Queen of Hearts' triploid and `Crimson Sweet' diploid watermelon seedlings were fertilized with N from calcium nitrate at 25, 75, or 225 mg·liter–1 and P from calcium phosphate at 5, 15, or 45 mg·liter–1. In the greenhouse, most variation in the shoot fresh and dry weights, leaf count, leaf area, transplant height, and root dry weight in `Queen of Hearts' and `Crimson Sweet' was attributed to N. Cultivar interacted with N, affecting all seedling growth variables, but not leaf area in Expt. 2. To a lesser extent, in Expt. 1, but not in Expt. 2, P interacted with cultivar, N, or cultivar × N and affected shoot fresh and dry weights, leaf count and leaf area. In the field, transplant shock increased linearly with N, regardless of cultivar or field location. The effect of PNC on plant growth diminished as the growing season progressed. For both cultivars at both locations, N and P PNC did not affect time to first staminate flower, fruit set, fruit width or length, soluble solids concentration, or yield. Vining at Charleston for both cultivars was 2 days earlier when N was at 75 rather than 25 mg·liter–1, without further change with the high N rate. At Clinton, the first pistillate flower was delayed linearly the higher the N rate for `Crimson Sweet'. At Charleston, hollow heart in the `Queen of Hearts' increased nearly 3 times when N PNC rate was tripled (from 75 or 225 mg·liter–1), while N had no effect on hollow heart in `Crimson Sweet'. In contrast, at Clinton, hollow heart in either cultivar was affected by P PNC, not N. PNC with 25N–5P (in mg·liter–1) can be used to reduce seedling growth and produce a more compact plant for easier handling, yet not reduce fruit quality or yield.

Damping-off of sugar beet in Finland: II. Disease control 

1983 ◽  
Vol 55 (5) ◽  
pp. 431-450
Author(s):  
Mauritz Vestberg ◽  
Risto Tahvonen ◽  
Kyösti Raininko
Keyword(s):  
Sugar Beet ◽  
Disease Control ◽  
Field Experiments ◽  
Damping Off ◽  
Good Protection ◽  
Great Damage

In pot and field experiments carried out in 1979-1981, the systemic funqicide hymexazol prevented satisfactorily soil borne damping-off of sugar beet caused mainly by the fungus Pythium debaryanum auct. non Hesse. The results with the combination hymexazol + thiram were still better. This treatment gave very good protection against the disease up to about two to three weeks after emergence, increased the yield on the average by 5-10 % and produced considerably thicker and denser stands. Thereafter a large number of beets may have become infected, but no great damage was caused as only few died. Band spraying at emergence using hymexazol with a large amount of water as well as spraying into the seed furrow prevented the outbreak of the disease almost completely. Liming had little effect on damping-off.

scholarly journals Effects of Interspecific Chromosome Substitution in Upland Cotton on Cottonseed Macronutrients

Plants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1158
Author(s):  
Nacer Bellaloui ◽  
Sukumar Saha ◽  
Jennifer L. Tonos ◽  
Jodi A. Scheffler ◽  
Johnie N. Jenkins ◽  
...  
Keyword(s):  
South Carolina ◽  
Upland Cotton ◽  
Field Experiments ◽  
Seed Quality ◽  
Recurrent Parent ◽  
Chromosome Substitution ◽  
Substitution Lines ◽  
Chromosome Substitution Lines ◽  
Macronutrient Content ◽  
Chromosome Arm

Nutrients, including macronutrients such as Ca, P, K, and Mg, are essential for crop production and seed quality, and for human and animal nutrition and health. Macronutrient deficiencies in soil lead to poor crop nutritional qualities and a low level of macronutrients in cottonseed meal-based products, leading to malnutrition. Therefore, the discovery of novel germplasm with a high level of macronutrients or significant variability in the macronutrient content of crop seeds is critical. To our knowledge, there is no information available on the effects of chromosome or chromosome arm substitution on cottonseed macronutrient content. The objective of this study was to evaluate the effects of chromosome or chromosome arm substitution on the variability and content of the cottonseed macronutrients Ca, K, Mg, N, P, and S in chromosome substitution lines (CS). Nine chromosome substitution lines were grown in two-field experiments at two locations in 2013 in South Carolina, USA, and in 2014 in Mississippi, USA. The controls used were TM-1, the recurrent parent of the CS line, and the cultivar AM UA48. The results showed major variability in macronutrients among CS lines and between CS lines and controls. For example, in South Carolina, the mean values showed that five CS lines (CS-T02, CS-T04, CS-T08sh, CS-B02, and CS-B04) had higher Ca level in seed than controls. Ca levels in these CS lines varied from 1.88 to 2.63 g kg−1 compared with 1.81 and 1.72 g kg−1 for TM-1 and AMUA48, respectively, with CS-T04 having the highest Ca concentration. CS-M08sh exhibited the highest K concentration (14.50 g kg−1), an increase of 29% and 49% over TM-1 and AM UA48, respectively. Other CS lines had higher Mg, P, and S than the controls. A similar trend was found at the MS location. This research demonstrated that chromosome substitution resulted in higher seed macronutrients in some CS lines, and these CS lines with a higher content of macronutrients can be used as a genetic tool towards the identification of desired seed nutrition traits. Also, the CS lines with higher desired macronutrients can be used as parents to breed for improved nutritional quality in Upland cotton, Gossypium hirsutum L., through improvement by the interspecific introgression of desired seed nutrient traits such as Ca, K, P, S, and N. The positive and significant (p ≤ 0.0001) correlation of P with Ca, P with Mg, S with P, and S with N will aid in understanding the relationships between nutrients to improve the fertilizer management program and maintain higher cottonseed nutrient content.

scholarly journals QTL Mapping Identifies Novel Source of Resistance to Fusarium Wilt Race 1 in Citrullus amarus

Plant Disease ◽  
2019 ◽  
Vol 103 (5) ◽  
pp. 984-989 ◽  
Author(s):  
Sandra E. Branham ◽  
Amnon Levi ◽  
W. Patrick Wechter
Keyword(s):  
Fusarium Wilt ◽  
Citrullus Lanatus ◽  
Recombinant Inbred Lines ◽  
The United States ◽  
Chromosome 9 ◽  
Mapping Study ◽  
Sources Of Resistance ◽  
Race 1 ◽  
Genetic Source ◽  
Genetic Mapping Study

Fusarium wilt race 1, caused by the soilborne fungus Fusarium oxysporum Schlechtend.: Fr. f. sp. niveum (E.F. Sm.) W.C. Snyder & H.N. Hans (Fon), is a major disease of watermelon (Citrullus lanatus) in the United States and throughout the world. Although Fusarium wilt race 1 resistance has been incorporated into several watermelon cultivars, identification of additional genetic sources of resistance is crucial if a durable and sustainable level of resistance is to be continued over the years. We conducted a genetic mapping study to identify quantitative trait loci (QTLs) associated with resistance to Fon race 1 in segregating populations (F2:3 and recombinant inbred lines) of Citrullus amarus (citron melon) derived from the Fon race 1 resistant and susceptible parents USVL246-FR2 and USVL114, respectively. A major QTL (qFon1-9) associated with resistance to Fon race 1 was identified on chromosome 9 of USVL246-FR2. This discovery provides a novel genetic source of resistance to Fusarium wilt race 1 in watermelon and, thus, an additional host-resistance option for watermelon breeders to further the effort to mitigate this serious phytopathogen.

scholarly journals Marker Development for Differentiation of Fusarium oxysporum f. sp. Niveum Race 3 from Races 1 and 2

2021 ◽  
Vol 22 (2) ◽  
pp. 822
Author(s):  
Owen Hudson ◽  
Sumyya Waliullah ◽  
James C. Fulton ◽  
Pingsheng Ji ◽  
Nicholas S. Dufault ◽  
...  
Keyword(s):  
South Carolina ◽  
Fusarium Oxysporum ◽  
Fusarium Wilt ◽  
Conventional Polymerase Chain Reaction ◽  
Detection Methods ◽  
Limiting Factors ◽  
Pcr Marker ◽  
Primer Sets ◽  
Race Differentiation ◽  
Race 2

Fusarium wilt of watermelon, caused by Fusarium oxysporum f. sp. niveum (FON), is pathogenic only to watermelon and has become one of the main limiting factors in watermelon production internationally. Detection methods for this pathogen are limited, with few published molecular assays available to differentiate FON from other formae speciales of F. oxysporum. FON has four known races that vary in virulence but are difficult and costly to differentiate using traditional inoculation methods and only race 2 can be differentiated molecularly. In this study, genomic and chromosomal comparisons facilitated the development of a conventional polymerase chain reaction (PCR) assay that could differentiate race 3 from races 1 and 2, and by using two other published PCR markers in unison with the new marker, the three races could be differentiated. The new PCR marker, FNR3-F/FNR3-R, amplified a 511 bp region on the “pathogenicity chromosome” of the FON genome that is absent in race 3. FNR3-F/FNR3-R detected genomic DNA down to 2.0 pg/µL. This marker, along with two previously published FON markers, was successfully applied to test over 160 pathogenic FON isolates from Florida, Georgia, and South Carolina. Together, these three FON primer sets worked well for differentiating races 1, 2, and 3 of FON. For each marker, a greater proportion (60 to 90%) of molecular results agreed with the traditional bioassay method of race differentiation compared to those that did not. The new PCR marker should be useful to differentiate FON races and improve Fusarium wilt research.

scholarly journals Reduced Dosage of Methyl Bromide for Controlling Verticillium Wilt of Potato in Experimental and Commercial Plots

Plant Disease ◽  
1997 ◽  
Vol 81 (5) ◽  
pp. 469-474 ◽  
Author(s):  
A. Gamliel ◽  
A. Grinstein ◽  
Y. Peretz ◽  
L. Klein ◽  
A. Nachmias ◽  
...  
Keyword(s):  
Verticillium Wilt ◽  
Methyl Bromide ◽  
Large Scale ◽  
Field Experiments ◽  
Tuber Yield ◽  
Total Yield ◽  
Effective Control ◽  
Large Scale Field ◽  
Commercial Applications

The use of gas-impermeable films to reduce the dosage of methyl bromide (MB) required to control Verticillium wilt in potatoes was examined in field experiments, conducted in soils naturally infested with Verticillium dahliae. The incidence and severity of Verticillium wilt were significantly reduced (by 74 to 94%) by fumigation with MB at 50 g/m2 under standard low density polyethylene (LDPE) or at 25 g/m2 under gas-impermeable films. Fumigation at 25 g/m2 under LDPE was less effective. Disease severity was inversely correlated (r2 = 0.89 to 0.91) with chlorophyll content in the leaves. Fumigation also reduced (by 89 to 100%) stem colonization by the pathogen. Potato yield in the fumigated plots was significantly higher (26 to 69%), than in their nonfumigated counterparts, and was inversely correlated with disease index (r2 = 0.69 to 0.9). The percentage of high-value tubers (above 45 g) was 52 to 56% of total yield in the fumigated plots as compared with 32 to 40% in the nonfumigated controls. Thus, fumigation also improved the commercial quality of tuber yield. Effective control of V. dahliae and yield increases following MB fumigation at the recommended dosage or at a reduced dosage with gas-impermeable films was also observed in a consecutive crop. These results were verified in a large-scale field experiment using commercial applications, further demonstrating the feasibility of reducing MB dosages under farm conditions, without reducing its effectiveness in terms of disease control and yield improvement.

scholarly journals Uji masa simpan pelet Trichoderma harzianum dan kemampuannya dalam menghambat perkembangan penyakit Layu Fusarium pada bibit tomat.

2018 ◽  
Vol 3 (2) ◽  
pp. 117-127
Author(s):  
Rizka Musfirah ◽  
Rina Sriwati ◽  
Tjut Chamzurni
Keyword(s):  
Vitamin A ◽  
Shelf Life ◽  
Fusarium Oxysporum ◽  
Solanum Lycopersicum ◽  
Plant Height ◽  
Incubation Period ◽  
Fusarium Wilt ◽  
Trichoderma Harzianum ◽  
Wilt Disease ◽  
Damping Off

Abstrak. Tomat (Solanum lycopersicum) merupakan salah satu komoditas pertanian yang ditanam secara luas di seluruh dunia, termasuk di Indonesia, karena memiliki rasa yang khas dan enak, juga memiliki nilai gizi seperti sumber vitamin A dan C yang sangat baik. Produksi tomat mengalami penurunan setiap tahun, salah satunya diakibatkan oleh organisme penganggu tanaman (OPT) yaitu patogen Fusarium oxysporum sehingga perlu dilakukan pengendalian hayati yaitu menggunakan Trichoderma harzianum dalam bentuk formulasi pelet yang praktis, efektif, dan efesien. Penelitian ini menggunakan Rancangan Acak Lengkap (RAL) non faktorial yang terdiri dari 6 perlakuan dengan 3 ulangan, setiap perlakuan terdiri dari 10 unit bibit tomat. Penelitian ini terdiri dari 6 perlakuan yaitu perlakuan A (masa simpan pelet T. harzianum  4 minggu), B (masa simpan pelet T. harzianum 3 minggu), C (masa simpan pelet T. harzianum 2 minggu), D (masa simpan pelet T. harzianum 1 minggu), E (masa simpan pelet T. harzianum 0 minggu), F (tanpa perlakuan pelet T. harzianum). Peubah yang diamati yaitu pre-emergence damping off, post-emergence damping off, masa inkubasi, persentase tanaman layu, tinggi tanaman, dan jumlah daun. Hasil penelitian menunjukkan bahwa pelet T. harzianum yang disimpan 4 minggu efektif dalam menghambat perkembangan penyakit layu fusarium seperti menunda masa inkubasi sampai 7 HSI, menekan pre-emergence damping off sampai 90%, post-emergence damping off 92,95%, serta mampu meningkatkan tinggi tanaman sampai 19,63 cm dan meningkatkan jumlah daun rata-rata 7 helai pada 35 HSI. (Storing Period of Trichoderma harzianum Pellets and its ability to Inhibit the development of Fusarium Wilt Disease on Tomato Seeds)Abstract. Tomato (Solanum lycopersicum) is one of the most widely grown commodities in the world, including Indonesia. It has a distinctively good taste and many nutritional value such as vitamin A and C. However, tomato production has decreased every year. One of the main cause is the attacks by pathogens, named Fusarium oxysporum. A Biological control is necessary and the use of Trichoderma harzianum in the form of pellets is recommended because of its effectiveness, efficiency and practical use. This research used a Completely Randomized Design (RAL) non-factorial consisted of 6 treatments with 3 replications, each treatment consisted of 10 units of tomato seedlings. The 6 treatments are named as treatment A (T. harzianum pellet saving 4 weeks), B (T. harzianum pellet saving period 3 weeks), C (shelf life of 2 weeks T. harzianum pellet), D (shelf life of pellet T harzianum 1 week), E (shelf life of pellet T. harzianum 0 weeks), and F (without T. harzianum pellet treatment). The variables observed in this study are pre-emergence damping off, post-emergence damping off, incubation period, the percentage of wilted plants, plant height, and the number of leaves. The results showed that pellets of T. harzianum stored 4 weeks effectively inhibiting the development of fusarium wilt disease such as delaying incubation period up to 7 HSI (Days After Incubation), suppressing the pre-emergence damping off up to 90% and post-emergence damping off to 92.95%, also able to increase the plant height up to 19.63 cm and increase the average leaf number of 7 strands at 35 HSI.

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