Powdery mildew of ornamental species caused by Oidiopsis haplophylli in Brazil

Summa Phytopathologica

Ailton Reis²  Leonardo Silva Boiteux²  Milton Luiz Paz-lima¹ 

[1] ,Embrapa Hortaliças Centro Nacional de Pesquisa de Hortaliças Brasília DF

关键词: etiology;    Leveillula taurica;    lisianthus;    calla lily;    nasturtium;    impatiens;    Asclepias physocarpa;    etiologia;    Leveillula taurica;    lisianthus;    copo-de-leite;    capuchinha;    impatiens;    Asclepias physocarpa;   

DOI  :  10.1590/S0100-54052007000400015

来源: SciELO

【 摘 要 】

Oidiopsis haplophylli (syn. Oidiopsis sicula) was identified as the causal agent of powdery mildew diseases occurring on five ornamental species in Brazil. This disease was observed in plastic house-grown lisianthus (Eustoma grandiflorum: Gentianaceae), in nasturtium (Tropaeolum majus: Tropaeolaceae) cultivated under open field conditions and in greenhouse-grown calla lily (Zantedeschia aethiopica: Araceae), impatiens (Impatiens balsamina: Balsaminaceae) and balloon plant (Asclepias physocarpa: Asclepiadaceae). Typical disease symptoms consisted of chlorotic areas on the upper leaf surface corresponding to a fungal colony in the abaxial surface. With the disease progression, these chlorotic areas eventually turned to necrotic (brown) lesions. Fungi morphology on all hosts was similar to that described for the imperfect stage of Leveillula taurica (O. haplophylli). The Koch's postulates were fulfilled by inoculating symptom-free plants via leaf-to-leaf contact with fungal colonies. Additional inoculations using an isolate of O. haplophylli from sweet pepper (Capsicum annuum) demonstrated that it is pathogenic to all five species belonging to distinct botanical families, indicating lack of host specialization. This is the first formal report of a powdery mildew disease on lisianthus, calla lilly, impatiens and nasturtium in Brazil. It is, to our knowledge, the first report of O. haplophyllii infecting A. physocarpa, extending the host range of this atypical powdery mildew-inducing fungus. This disease might become important on these ornamental crops especially in protected cultivation and also under field conditions in hot and dry areas of Brazil.

【 授权许可】

CC BY   
 All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License