Horticultura Brasileira (2004) 22, 628-631

Ailton Reis and José Amauri Buso (2004)
Levantamento preliminar de raças de Sphaerotheca fuliginea no Brasil
[Preliminary survey of Sphaerotheca fuliginea races occurring in cucurbits in Brazil]
Horticultura Brasileira 22 (3), 628-631
Abstract: Sphaerotheca fuliginea is the causal agent of powdery mildew, one of the most important cucurbit diseases in Brazil. Disease control is achieved by using fungicides, but resistant varieties of cultivars can also be used. This fungus presents physiological specificity in melons with race 1 being apparently prevalent in Brazil and world wide. Knowledge of prevalent races of the pathogen in a specific region is of vital importance to plant breeders. In this research a total of 31 isolates was obtained from different cucurbit species, showing symptoms of powdery mildew, cultivated in several Brazilian States. All isolates were identified as S. fuliginea. Isolates were maintained on plants growing in the greenhouse and evaluated for virulence on a set of differential melon and one watermelon cultivars. Twenty-one isolates were identified as race 1, and eight as race 2. Two isolates from watermelon were considered specific to this species because they infected only the cultivar "Crimson Sweet" of watermelon. Race 1 is the most prevalent in Brazil and race 2 is present in the Federal District. Race 2 seems to be adapted to greenhouse conditions as the isolates from this race were found only under this specific condition. This is the first report of race 2 of S. fuliginea in the Federal District of Brazil.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
(original language: Portuguese)
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Research topic(s) for pests/diseases/weeds:
surveys/sampling/distribution
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Podosphaera fuliginea	Melon (Cucumis melo)	Brazil (south)
	Podosphaera fuliginea	Melon (Cucumis melo)	Brazil (NE)
	Podosphaera fuliginea	Watermelon/colocynth (Citrullus)	Brazil (south)
	Podosphaera fuliginea	Squash/pumpkin (Cucurbita)	Brazil (south)