Screening of tomato varieties for resistance to major fungal diseases and bacterial wilt

The resistance of local and introduced tomato varieties to early blight (Alternaria solani Sorauer) and late blight (Phytopthora infestans (Mont.) de Bary) were evaluated in the field and to bacterial wilt (Ralstonia solanacearum) were tested under artificial infection in greenhouse conditions. Three varieties (De-brao krasnii, De-brao Rozovii and Sultan F1) showed the moderate resistance to early blight, while the only two varieties (De-brao krasnii and De-brao Rozovii) were moderate resistant to late blight. The remaining samples showed susceptibility to disease. The tested varieties showed a different degree of resistance to the bacterial wilt. Four varieties: Rozovii Gigant, Krachodarskii Krasnii,Tarasenko and Lagidnii appeared to be resistant; Two varieties: Fakel and Polbig showed the moderate resistance and the rest ten varieties were susceptible to the disease.

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An Assessment of Fungicide Benefits for the Control of Fungal Diseases of Processing Tomatoes in New York and New Jersey

Plant Disease ◽

10.1094/pdis.1997.81.6.677 ◽

1997 ◽

Vol 81 (6) ◽

pp. 677-681 ◽

Cited By ~ 7

Author(s):

H. R. Dillard ◽

S. A. Johnston ◽

A. C. Cobb ◽

G. H. Hamilton

Keyword(s):

New York ◽

New Jersey ◽

Early Blight ◽

Warning System ◽

Alternaria Solani ◽

Additional Treatment ◽

Fungal Diseases ◽

Financial Benefit ◽

Financial Benefits ◽

Processing Tomatoes

Concurrent studies on the benefits of fungicide use for control of fungal diseases of processing tomatoes were conducted in New York and New Jersey in 1993 and 1994. Fungicides (chlorothalonil at 2.5 kg/ha or mancozeb at 1.68 kg/ha) were applied at 7-, 10-, or 14-day intervals to processing tomatoes for control of anthracnose caused by Colletotrichum coccodes, early blight caused by Alternaria solani, and Septoria leaf spot caused by Septoria lycopersici. The New Jersey trial included an additional treatment using the disease-warning system TOM-CAST. All fungicide treatments significantly reduced foliar disease severity (in New York) and anthracnose incidence (New York and New Jersey) in the 2 years of study. Yield of usable fruit was significantly increased by all fungicide treatments with the exception of the TOM-CAST treatment using the cultivar Brigade in 1994 in New Jersey. In New York, usable yield and financial benefit were consistently the highest in plots treated with chlorothalonil on a 7-day interval. In New Jersey, the highest usable yields and the greatest financial benefits occurred in the chlorothalonil 7- and 10-day interval treatments in 1993. At both locations, the yield and financial benefit associated with the fungicide treatments was primarily due to suppression of anthracnose and other fruit rots. Suppression of foliar diseases was less important.

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Severity of late blight (Phytophthora infestans /Mont./ de Bary) and early blight of potato (Alternaria solani Sorauer, A. alternata /Fr./ Keissler) in three potato cultivars under differentiated soil and foliar fertilization

Journal of Elementology ◽

10.5601/jelem.2012.17.3.02 ◽

2012 ◽

Author(s):

Bożena Cwalina-Ambroziak ◽

Bożena Bogucka

Keyword(s):

Late Blight ◽

Phytophthora Infestans ◽

Early Blight ◽

Alternaria Solani ◽

Potato Cultivars ◽

Foliar Fertilization

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Evaluation of tomato genotypes for tolerance to major diseases in Uganda

African Crop Science Journal ◽

10.4314/acsj.v29i2.5 ◽

1970 ◽

Vol 29 (2) ◽

pp. 241-258

Author(s):

I. Ramathani ◽

G. Ddamulira ◽

A. Kangire ◽

P. Wasswa ◽

A. Tusiime

Keyword(s):

Late Blight ◽

Bacterial Wilt ◽

Early Blight ◽

Bacterial Speck ◽

Solanum Lycopersicum L ◽

Genetic Base ◽

National Performance ◽

Tomato Diseases ◽

Tomato Bacterial Wilt ◽

Tomato Genotypes

Tomato (Solanum lycopersicum L.) is a priority vegetable in Uganda, but due to its limited genetic base, its cultivated types are prone to a variety of diseases. The objective of this study was to evaluate new tomato genotypes for resistance to major tomato diseases under hotspot conditions in Uganda. Fourty-five tomato genotypes were evaluated for reactions to tomato bacterial wilt, tomato bacterial speck, early blight and late blight. The study was conducted for two rainy seasons in 2019, at the National Crops Resources Research Institute, Namulonge in Uganda. Data for severity and incidence were collected at two-week intervals after transplanting. Twelve genotypes (Nouvella F1, Rambo F1, Commando F1, AVTO1315, AVTO922, AVTO1701, AVTO1219, AVTO1464, MT56, ADV1287A, Pruna and Vega) exhibited high levels of tolerance to bacterial wilt; while bacterial speck presented mild symptoms majorly seen on Vega, Zodiac and AVTO9802. Rhino, AVTO1418, AVTO1314, Eureka, Roma VFN, MT56, Pinktop, Assila F1, Money-maker, AVTO0922 and AVTO1464 were the least affected by early blight; while AVTO1219, AVTO1701, ADV12021, ADV12076 and ADV1287A expressed low AUDPC values for late blight. Overall, AVTO1315 was the best yielder (30.8 metric tonnes ha-1), followed by AVTO0301 (29.0 t ha-1) and Nouvella F1 (26.1 t ha-1). Among the tomato genotypes evaluated, we recommend AVTO1701, AVTO0922, AVTO1464, AVTO0301 AVTO1315, AVTO1219, Pruna, Vega, ADV1287A and MT56 for the national performance trials.

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Essential Oils as Biocontrol Agents of Early and Late Blight Diseases of Tomato under Greenhouse Conditions

International Journal of Agronomy ◽

10.1155/2021/5719091 ◽

2021 ◽

Vol 2021 ◽

pp. 1-10

Author(s):

Lydia G. Mugao ◽

Bernard M. Gichimu ◽

Phyllis W. Muturi ◽

Ezekiel K. Njoroge

Keyword(s):

Late Blight ◽

Essential Oils ◽

Early Blight ◽

Growth Yield ◽

Alternaria Solani ◽

Positive Control ◽

Negative Control ◽

Distilled Water ◽

Tomato Production ◽

Tomato Plants

Tomato production worldwide is usually restrained by various infections, among them mainly the late and early blight caused by Phytophthora infestans and Alternaria solani, respectively. Lately, there has been a growing concern over the use of synthetic fungicides on environmental and food safety, hence the need to explore other alternatives that are friendly to the user, the consumer, and the general environment. This research sought to test the potency of ginger, garlic, and Mexican marigold essential oils against the early and late blight diseases of tomato under greenhouse conditions. A synthetic fungicide (Ridomil Gold®) was used as a positive control while distilled water acted as a negative control. The extraction of essential oils was done by dry steam distillation and then mixed with tween twenty before being topped up with sterile distilled water. They were then used to spray tomato plants that had been inoculated with A. solani and P. infestans isolates under greenhouse conditions. The tomato plants were evaluated for growth, yield, and disease severity. The data obtained was subjected to ANOVA and separation of means was conducted using Student–Newman–Keul (SNK) test at 95% level of confidence. The three essential oils had a significant potency against the two diseases which is comparable to the synthetic fungicide. Marigold essential oil was also found to have a significant impact on the general growth of sprayed tomato plants. Essential oils of the three plants can be further explored as alternative products management of the two diseases.

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Ralstonia solanacearum Needs Motility for Invasive Virulence on Tomato

Journal of Bacteriology ◽

10.1128/jb.183.12.3597-3605.2001 ◽

2001 ◽

Vol 183 (12) ◽

pp. 3597-3605 ◽

Cited By ~ 201

Author(s):

Julie Tans-Kersten ◽

Huayu Huang ◽

Caitilyn Allen

Keyword(s):

Bacterial Wilt ◽

Ralstonia Solanacearum ◽

Soft Agar ◽

Cell Protein ◽

In Planta ◽

Tomato Plants ◽

Bacterial Wilt Disease ◽

Virulence Assay ◽

Flagellar Filament

ABSTRACT Ralstonia solanacearum, a widely distributed and economically important plant pathogen, invades the roots of diverse plant hosts from the soil and aggressively colonizes the xylem vessels, causing a lethal wilting known as bacterial wilt disease. By examining bacteria from the xylem vessels of infected plants, we found thatR. solanacearum is essentially nonmotile in planta, although it can be highly motile in culture. To determine the role of pathogen motility in this disease, we cloned, characterized, and mutated two genes in the R. solanacearum flagellar biosynthetic pathway. The genes for flagellin, the subunit of the flagellar filament (fliC), and for the flagellar motor switch protein (fliM) were isolated based on their resemblance to these proteins in other bacteria. As is typical for flagellins, the predicted FliC protein had well-conserved N- and C-terminal regions, separated by a divergent central domain. The predicted R. solanacearum FliM closely resembled motor switch proteins from other proteobacteria. Chromosomal mutants lackingfliC or fliM were created by replacing the genes with marked interrupted constructs. Since fliM is embedded in the fliLMNOPQR operon, the aphAcassette was used to make a nonpolar fliM mutation. Both mutants were completely nonmotile on soft agar plates, in minimal broth, and in tomato plants. The fliC mutant lacked flagella altogether; moreover, sheared-cell protein preparations from the fliC mutant lacked a 30-kDa band corresponding to flagellin. The fliM mutant was usually aflagellate, but about 10% of cells had abnormal truncated flagella. In a biologically representative soil-soak inoculation virulence assay, both nonmotile mutants were significantly reduced in the ability to cause disease on tomato plants. However, the fliC mutant had wild-type virulence when it was inoculated directly onto cut tomato petioles, an inoculation method that did not require bacteria to enter the intact host from the soil. These results suggest that swimming motility makes its most important contribution to bacterial wilt virulence in the early stages of host plant invasion and colonization.

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