scholarly journals Fusarium oxysporum f.sp. niveum (Fusarium wilt of watermelon).

Author(s):  
Anthony Keinath

Abstract Fusarium wilt of watermelon occurs throughout the world and is often a limiting factor in watermelon production. In China, 20-30% of watermelon production is normally lost in infested areas, and 100% mortality has been observed in fields planted with susceptible cultivars in Zhejiang Province (Lin, 1990). In a survey of 62 watermelon crops grown in plastic tunnels throughout the main production area of Cyprus, Fusarium wilt was found in all fields sampled despite the use of resistant cultivars (mainly Crimson Sweet). Mean incidence ranged from 37 to 70% in 1985 and 1986, and mean yields of marketable fruit were 38 and 10 t/ha, respectively (Ioannou and Poullis, 1991). In Aydin Province, Turkey, incidence ranged from 0.2 to 12% in fields in which the pathogen was isolated from symptomatic plants (Erİncİk and Döken, 2018). In Spain, in soil infested with unidentified races of F. oxysporum f.sp. niveum, yield loss in a triploid cultivar was 42 to 68% (Miguel et al., 2004). In South Carolina and Georgia, USA, yield losses in research fields naturally infested with race 2 averaged 62 and 83%, respectively, which represented a 91 and 55% loss in net returns per hectare, respectively, based on an average price of $USD 0.35 per kilogram of seedless watermelon fruit.

2021 ◽  
Author(s):  
Anthony Keinath

Abstract Fusarium wilt of watermelon occurs throughout the world and is often a limiting factor in watermelon production. In China, 20-30% of watermelon production is normally lost in infested areas, and 100% mortality has been observed in fields planted with susceptible cultivars in Zhejiang Province (Lin, 1990). In a survey of 62 watermelon crops grown in plastic tunnels throughout the main production area of Cyprus, Fusarium wilt was found in all fields sampled despite the use of resistant cultivars (mainly Crimson Sweet). Mean incidence ranged from 37 to 70% in 1985 and 1986, and mean yields of marketable fruit were 38 and 10 t/ha, respectively (Ioannou and Poullis, 1991). In Aydin Province, Turkey, incidence ranged from 0.2 to 12% in fields in which the pathogen was isolated from symptomatic plants (Erİncİk and Döken, 2018). In Spain, in soil infested with unidentified races of F. oxysporum f.sp. niveum, yield loss in a triploid cultivar was 42 to 68% (Miguel et al., 2004). In South Carolina and Georgia, USA, yield losses in research fields naturally infested with race 2 averaged 62 and 83%, respectively, which represented a 91 and 55% loss in net returns per hectare, respectively, based on an average price of $USD 0.35 per kilogram of seedless watermelon fruit (Keinath et al., 2019a).


2021 ◽  
Vol 22 (2) ◽  
pp. 822
Author(s):  
Owen Hudson ◽  
Sumyya Waliullah ◽  
James C. Fulton ◽  
Pingsheng Ji ◽  
Nicholas S. Dufault ◽  
...  

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.


Plant Disease ◽  
2019 ◽  
Vol 103 (1) ◽  
pp. 44-50 ◽  
Author(s):  
Anthony P. Keinath ◽  
Timothy W. Coolong ◽  
Justin D. Lanier ◽  
Pingsheng Ji

Fusarium wilt of watermelon caused by Fusarium oxysporum f. sp. niveum is a serious, widespread disease of watermelon throughout the southern United States. To investigate whether soil temperature affects disease development, three cultivars of triploid watermelon were transplanted March 17 to 21, April 7 to 11, and April 26 to May 2 in 2015 and 2016 at Charleston, SC, and Tifton, GA into fields naturally infested with F. oxysporum f. sp. niveum. Incidence of Fusarium wilt was lower with late-season than with early and midseason transplanting in all four experiments (P ≤ 0.01). Cultivar Citation had more wilted plants than the cultivars Fascination and Melody in three of four experiments (P ≤ 0.05). In South Carolina, planting date did not affect weight and number of marketable fruit ≥4.5 kg apiece. In Georgia in 2016, weight and number of marketable fruit were greater with late transplanting than with early and midseason transplanting. In both states, yield and value for Fascination and Melody were higher than for Citation. Soil temperature averaged over the 4-week period after transplanting was negatively correlated with disease incidence for all four experiments (r = –0.737, P = 0.006). Transplanting after mid-April and choosing a cultivar with resistance to F. oxysporum f. sp. niveum race 1, like Fascination, or tolerance, like Melody, can help manage Fusarium wilt of watermelon and increase marketable yields in the southern United States.


Plant Disease ◽  
2014 ◽  
Vol 98 (2) ◽  
pp. 255-266 ◽  
Author(s):  
A. P. Keinath ◽  
R. L. Hassell

Grafting watermelon (Citrullus lanatus var. lanatus) onto rootstocks of interspecific hybrid squash (Cucurbita moschata × C. maxima), bottle gourd (Lagenaria siceraria), or citron (Citrullus lanatus var. citroides) has been used in Asia and Israel to mange Fusarium wilt of watermelon caused by Fusarium oxysporum f. sp. niveum. The objectives of this study were to determine the frequency of infection of six rootstocks by F. oxysporum f. sp. niveum races 1 and 2 and the field performance of grafted rootstocks in Charleston, SC. Grafted and nongrafted watermelon and rootstock plants were inoculated in the greenhouse with race 1, race 2, or water (the control treatment). With both races, the frequency of recovery of F. oxysporum from scion and rootstock portions of inoculated watermelon plants grafted onto ‘Ojakkyo’ citron was greater than from watermelon plants grafted onto ‘Shintosa Camel’ and ‘Strong Tosa’ interspecific hybrid squash, and from plants grafted onto ‘Emphasis’, ‘Macis’, and ‘WMXP 3945’ bottlegourd. For nongrafted plants inoculated with race 1, percent recovery also was greater from Ojakkyo than from interspecific hybrid squash and bottlegourd. For nongrafted plants inoculated with race 2, F. oxysporum was recovered from the base of ≥79% of all inoculated plants. More than two-thirds (15) of 21 isolates recovered from the tops or scions of inoculated plants were pathogenic on watermelon. In spring 2010 and 2011, the six rootstocks were grafted with seedless watermelon ‘Tri-X 313’, which is susceptible to both races, and transplanted in a field infested with races 1 and 2 of F. oxysporum f. sp. niveum. Disease incidence for nongrafted and self-grafted Tri-X 313 (the control treatments) and Tri-X 313 grafted onto Ojakkyo citron did not differ significantly. Grafted watermelon plants produced greater weights and numbers of fruit than plants of the two control treatments. Nonpathogenic isolates of F. oxysporum and isolates of F. oxysporum f. sp. niveum colonized interspecific hybrid squash, bottlegourd, and grafted watermelon. The rootstocks evaluated, however, restricted movement of F. oxysporum f. sp. niveum into the watermelon scion, suppressed wilt symptoms, and increased fruit yields in an infested field.


HortScience ◽  
2005 ◽  
Vol 40 (3) ◽  
pp. 529-531 ◽  
Author(s):  
James D. McCreight ◽  
Michael E. Matheron ◽  
Barry R. Tickes ◽  
Belinda Platts

Three races of Fusarium oxysporum f.sp. lactucae, cause of fusarium wilt of lettuce, are known in Japan, where the pathogen was first observed in 1955. Fusarium wilt first affected commercial U.S. lettuce production in 1990 in Huron, Calif., but did not become a serious problem in the U.S. until 2001 when it reappeared in Huron and appeared in the Yuma, Arizona lettuce production area. Reactions of three fusarium wilt differentials (`Patriot', susceptible to races 1, 2 and 3; `Costa Rica No. 4', resistant to race 1, and susceptible to races 2 and 3; and `Banchu Red Fire', susceptible to races 1 and 3, and resistant to race 2) in a naturally-infected commercial field test and artificially-inoculated greenhouse tests, indicated presence of race 1 in the Yuma lettuce production area. Reactions of these differentials to an isolate from Huron confirmed the presence of race 1 in that area. Consistent with previous results from the U.S. and Japan, `Salinas' and `Salinas 88' were resistant to the Yuma and Huron isolates of race 1, whereas `Vanguard' was highly susceptible. Limited F1 and F2 data indicate that resistance to race 1 in `Costa Rica No. 4' and `Salinas' is recessive. `Calmar' is the likely source of resistance in `Salinas' and `Salinas 88'.


Plant Disease ◽  
2010 ◽  
Vol 94 (11) ◽  
pp. 1376-1376 ◽  
Author(s):  
P. Sánchez-Peña ◽  
S. O. Cauich-Pech ◽  
J. Núñez-Farfán ◽  
R. D. Núñez-Cebreros ◽  
S. Hernández-Verdugo ◽  
...  

Sinaloa State is the main producer of tomatoes (Solanum lycopersicum L) in Mexico where production attained 15,784 ha in 2008 (3). Fusarium wilt of tomato caused by Fusarium oxysporum f. sp. lycopersici (Sacc) Snyder & Hansen causes significant yield losses in Sinaloa each year (2). Three pathotypes or races of F. oxysporum f. sp. lycopersici have been described: races 1, 2, and 3 (1). The purpose of this study was to determine the races of F. oxysporum f. sp. lycopersici present in Sinaloa and distribution of these races in the region. F. oxysporum f. sp. lycopersici isolates were obtained from plants showing symptoms of yellowing and necrosis of vascular bundles. Plants were sampled from 50 fields throughout the production area in Sinaloa from November 2008 to March 2009. Four differential cultivars were used to identify the races of 26 F. oxysporum f. sp. lycopersici isolates collected across Sinaloa: Bonny Best (susceptible to all races), UC-82-L (susceptible to races 2 and 3), F1 MH-1 (susceptible to race 3), and IR-3 (resistant to all races). A microconidial suspension was prepared for each isolate (1 × 106 CFU/ml) from cultures grown in potato dextrose broth with constant agitation (110 rpm) at 28°C for 7 days. Five 25-day-old seedlings (three fully expanded true leaves) from each differential cultivar were immersed in the appropriate microconidial suspension for 10 min, then individually transplanted into a pot containing 1 kg of sterilized commercial potting mix, and grown in a growth chamber at 25 to 28°C and 60 to 75% relative humidity for 5weeks with 14-h light/10-h darkness. Control plants (root dipped for 10 min in sterile water) were grown similarly and remained asymptomatic. Susceptible cv. Bonny Best showed typical symptoms of Fusarium wilt including epinasty, yellowing, defoliation, vascular necrosis, and wilt. None of these plants survived 25 days postinoculation for any of the isolates. All UC-82-L plants inoculated with each of the 26 isolates died before 35 days, indicating that none of the isolates was of race 1. F1 MH-1 plants only survived inoculation with 3 of the 26 isolates (11.5%), indicating that the 23 isolates that killed these plants (88.5% of the 26 isolates) were of race 3, and only 3 isolates were of race 2. All IR-3 plants inoculated with the 26 isolates survived. The isolates showed variation in response to the differential cultivar UC-82L in duration from inoculation to when the plants died (variation in isolate aggressiveness). The three F. oxysporum f. sp. lycopersici race 2 isolates were restricted to the Culiacan Valley, whereas the 23 F. oxysporum f. sp. lycopersici race 3 isolates were widely distributed across Sinaloa. Koch's postulates were confirmed by reisolating the fungus from the roots and stem base of each dead, inoculated plant (4). This study provides baseline data for future surveys to monitor changes in distribution of F. oxysporum f. sp. lycopersici races in Sinaloa, Mexico. References: (1) G. Cai et al. Phytopathology 93:1014, 2003. (2) P. Sánchez-Peña. Programa de Fomento y Apoyo a Proyectos de Investigación (PROFAPI), Universidad Autónoma de Sinaloa, México, 2007. (3) Secretaría de Agricultura, Ganadería, Desarrollo Rural, Pesca y Alimentación, Servicio de Información Agroalimentaria y Pesquera, México. www.siap.gob.mx , 2009. (4) B. A. Summerell et al. Plant Dis. 87:117, 2003.


2006 ◽  
Vol 86 (Special Issue) ◽  
pp. 1395-1400 ◽  
Author(s):  
X. Hao ◽  
Q. Wang ◽  
S. Khosla

While CO2 enrichment generally benefits tomato fruit production in winter its effects on summer tomato production (under high air temperature and strong ventilation) are still not clear, especially when the crop has been subjected to long-term CO2 enrichment in winter. Therefore, a study was initiated in 2005 to determine the feasibility of summer CO2 enrichment in southwestern Ontario, a major greenhouse vegetable production area in North America with very hot summers. The long tomato crop (cv. Rapsodie) was planted into rockwool slabs in six greenhouse compartments in January. From January to the middle of June, the tomato plants in all six greenhouse compartments were subjected to the same standard CO2 enrichment practice. From the end of June to August, three CO2 treatments (two compartments for each treatment) were applied: Control (ambient/no enrichment), Enrich1 (800 µL L-1 when ventilation was less than 10% and 400 µL L-1 when less than 50%) and Enrich2 (1200 µL L-1 when ventilation was less than 10% and 500 µL L-1 when less than 50%). In all treatments, CO2 enrichment ceased when ventilation requirement was more than 50%. Leaf photosynthesis, as indicated by the CO2 response curve, partially acclimated to the CO2 enrichment. Marketable fruit yield was reduced by the summer CO2 enrichment. Leaf deformation [short, thick, curled and somewhat crisp, dark grey-green leaves, so-called short leaf syndrome (SLS)] was observed in the greenhouse compartments with summer CO2 enrichment. SLS developed under high light intensity and high CO2 concentration might have limited response of the tomato crop to summer CO2 enrichment. Further investigation on the cause and mechanism of SLS is needed to improve the response of greenhouse tomatoes to summer CO2 enrichment. Key words: Photosynthesis, Lycopersicon esculentum, high temperature stress, acclimation


2004 ◽  
Vol 158 (1) ◽  
pp. 107-112 ◽  
Author(s):  
M.D. Castillo ◽  
H.H.L. González ◽  
E.J. Martínez ◽  
A.M. Pacin ◽  
S.L. Resnik

1963 ◽  
Vol 16 (1) ◽  
pp. 55 ◽  
Author(s):  
A Kerr

At least four fungal pathogens are involved in the root rot-Fusarium wilt complex of peas which is a serious problem following intensive cropping of peas in South Australia. The pathogens are Fusarium oxysporum f. pisi race 2 Snyder & Hansen, F. solani f. pisi Snyder & Hansen, Pythium ultimum Trow, and Ascochyta pinodella L. K. Jones. In susceptible pea cultivars there is a marked interaction between F. oxysporum and P. ultimum. P. ultimum alone causes initial stunting from which plants gradually recover; F. OX1Jsporum alone probably CRuses little damage; both fungi together CRuse initial stunting followed by severe wilt symptom about 6 weeks after sowing and death 2 weeks later. The importance ofF. solani and A. pinodella has not been fully determined, but they probably cause only minor damage.


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