ABSTRACT One of the emerging biotic problems lettuce (Lactuca sativa) crop in Brazil is black root rot caused by two Berkeleyomyces species, B. basicola and rouxiae. Although sources resistance have already been reported for basicola, there still no information about response distinct accessions to Herein, we evaluated a diversified germplasm collection, composed from different L. sativa morphotypes, searching genetic effective against isolates both causal agents disease complex. Sixty-eight...

Abstract Castor bean ( Ricinus communis ) is a crop of great economic importance in Brazil. It used for producing oil the manufacture cosmetics and biodiesel. The genus Phytophthora contains pathogens with wide range host plants, including ornamentals, fruit vegetable crops. Among symptoms induced by species are collar root rot. This study aimed to identify causing rot castor seedlings Federal District test their pathogenicity. Samples symptomatic plants were collected four satellite cities...

The three races of Fusarium oxysporum f. sp. lycopersici (FOL) are important tomato pathogens throughout the world, causing severe economic losses (1). In Brazil, 1 and 2 widespread, but current geographic distribution race 3 is restricted to mild climate areas Espírito Santo Rio de Janeiro States in southeast region (2,3). Here we report spread FOL warm northeast Brazil. Plants commercial fields hybrid 'Alambra' (resistant 2) were found displaying chlorosis, vascular browning, wilt symptoms...

Fusarium wilt caused by oxysporum f. sp. lactucae (FOLAC) is one of the most important problems for lettuce growers because it causes major losses in production. To identify cultivars with potential use management disease, 102 accessions were evaluated resistance to isolates race 1 FOLAC. Initially, preliminary screening was done, using isolate Fus-173. Then, 47 materials selected as highly resistant and a susceptible control (Regina) reevaluated other FOLAC from different locations: Fus-202...

The objective of this work was to assess the virulence lettuce cultivars and host specificity identify races Fusarium oxysporum f. sp. lactucae (FOLac) isolates associated with wilt in Brazil. Thirty-one identified based on morphology were inoculated a set for race determination. Plantlets 'Elisa', 'Vera', 'Red Salad Bowl' all using root-dipping method. Isolates also species Asteraceae other botanical families. 'Elisa' 'Vera' susceptible 27 while resistant isolates. Plants than not infected...

To report the characterization of 120 Alternaria isolates inducing early blight-like foliar lesions in nine species five Solanaceae genera collected across all macrogeographical Brazilian regions.Phylogenetic relationships were assessed via analyses alternata allergenic protein-coding, glyceraldehyde-3-phosphate dehydrogenase and calmodulin gene sequences. Most tomato placed into linariae cluster, whereas most potato grouped with grandis. Novel host-pathogen interactions also reported....

This study aimed to identify Pythium and Phytopythium species from weeds collected in vegetable fields test their pathogenicity. Weeds with symptoms of damping-off, root rot or wilt were sampled the Brazilian states Ceará, Goiás Pernambuco, as well Distrito Federal, for isolation identification causal agents. Once isolated, colonies typical characteristics grew selective V8 medium. Procedures included morphology amplification ITS Cox II regions, which compared other accessions available at...

Physiological race determination of 143 Fusarium oxysporum f. sp. lycopersici (FOL) isolates collected along 30 years in major tomato‐producing regions Brazil. races were determined via root‐dipping inoculation differential tomato accessions and by the PCR‐based marker system Hirano Arie (2006). According to pathogenicity/virulence assays, five 1, 23 2 115 3 identified. FOL 1 prevailed up early 2000s. Afterwards, large majority was classified as invasive 3. Novel reports done states, thus...

<title>Abstract</title> Black root rot, caused by two <italic>Berkeleyomyces</italic> species, is a major disease of lettuce in tropical and subtropical areas. The most promising strategy for management these polyphagous aggressive pathogens the deployment genetic resistance. heirloom cultivar ‘La Brillante’ displayed resistant reaction against broad range isolates both species (<italic>B. basicola</italic> <italic>B. rouxiae</italic>). Inheritance studies investigating resistance to were...

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<title>Abstract</title> The ‘spotted wilt’ disease (induced by a complex of orthotospoviruses) is one the main biotic constraints lettuce (<italic>Lactuca sativa</italic> L.) production in South America. Genetic resistance to orthotospoviruses most practical and sustainable management strategy due low efficiency chemical control their thrips vectors. Thus far, conventional breeding sources have been detected genus <italic>Lactuca</italic> only tomato spotted wilt orthotospovirus (TSWV)...

Abstract Pythium tracheiphilum is a narrow host range oomycete first described infecting lettuce in Italy. Subsequently, the pathogen was reported many other countries. From 2015 to 2019, isolates were recovered from plants with symptoms of leaf rot, wilting and vascular necrosis, collected commercial fields different rural localities Brasilia‐DF, Brazil. The identified as P. based on morphological molecular genetic analysis. Pathogenicity tests conducted four confirmed that pathogenic...