Control of downy mildew (Pseudoperonospora cubensis) of greenhouse grown cucumbers with alternative biological agents
Control of downy mildew (Pseudoperonospora cubensis) of greenhouse grown cucumbers with alternative biological agents. In Communications in Agriculture and Applied Biological Sciences 75(4) (pp. 541–554), Ghent University.
Cucurbit downy mildew (Pseudoperonospora cubensis)—biology, ecology, epidemiology, host-pathogen interaction and control Aleš Lebeda & Yigal Cohen Accepted: 5 July 2010 /Published online: 25 July 2010 # KNPV 2010 Abstract Cucurbit downy mildew, caused by the oomycete Pseudoperonospora cubensis , is a devastating,
Published in: European Journal of Plant Pathology · 2011Authors: A Lebeda · Yigal CohenAffiliation: Bar Ilan UniversityAbout: Systematics · Genetically modified crops · Pesticide · Pseudoperonospora cubensis
Downy mildew of cucumber is caused by Pseudoperonospora cubensis, a member of the water mold group (Oomycota) of fungal-like organisms. The downy mildew pathogen is an obligate parasite that needs living cucurbit plants in order to grow and survive.
Pseudoperonospora cubensis is an obligate oomycete pathogen, infecting crops within the Cucurbitaceae family. The disease is characterized by angular chlorotic lesions and a downy or felt-like appearance on the abaxial side of the leaf. Control of this pathogen includes use of resistant cucumber cultivars and costly fungicide programs. Continuous use has led to resistance to commonly used fungicides.
In organic cucumber production the infection with downy mildew (Pseudoperonospora cubensis) is one of the major problems. Plant extracts from Salvia officinalis (sage) and Glycyrrhiza glabra L., a plant belonging to the family Fabaceae, as well as cultures of Brevibacillus brevis Nagano were investigated for their efficacy under commercial growing conditions.
Downy mildew, caused by Pseudoperonospora cubensis, is an important disease of all these crops, especially in areas with high humidity and rainfall (e.g., the eastern U.S.). In most years the disease is an annual, late-season problem on squash and pumpkin in the eastern and central US, however, since 2004 it has become one of the most important diseases in cucumber production  .
Downy mildew, caused by the fungal organism Pseudoperonospora cubensis, is most destructive to cucumber and cantaloupe, though all cucurbits are susceptible. Symptoms first appear as pale green areas on the upper leaf surfaces. These change to yellow angular spots. A fine white-to-grayish downy growth soon appears on the lower leaf surface.
Downy mildew on cucumbers is caused by an oomycete pathogen, Pseudoperonospora cubensis, which attacks plant leaves. A chlorotic, yellow area appears on the upper leaf surface, which then expands to cover the whole leaf.
Downy mildew is a potentially serious disease of cucumber (Cucumis sativum) caused by Pseudoperonospora cubensis. Two bacterial antagonists (Bacillus subtilus …
Downy mildew of cucurbits is a foliar disease, and is easily recognizable by the development of chlorotic lesions on the adaxial leaf surface, sometimes with necrotic centres.
Downy mildew is a serious disease of cucurbit crops grown in Ontario (Figure 1). It is caused by the fungus-like water mould Pseudoperonospora cubensis . Once established in a region, the disease can spread rapidly, causing significant loss of fruit quality and yield.
Cucurbitaceae downy mildew (caused by Pseudoperonospora cubensis) is specific to cucurbits (e.g., cantaloupe (Cucumis melo), cucumber (Cucumis sativus), pumpkin, squash, watermelon (Citrullus lanatus) and other members of the gourd family). The disease is one of the most significant diseases of cucurbits worldwide.
Causal agents: oomycetes
Pseudoperonospora cubensis is a species of water mould known for causing downy mildew on cucurbits such as cantaloupe, cucumber, pumpkin, squash and watermelon. This water mould is an important pathogen of all these crops, especially in areas with high humidity and …
In semi-commercial trials in greenhouse grown cucumbers, the efficacy of a 3 % G. glabra extract against downy mildew reached 70 to 83 % (Scherf et al. 2010). However, information on active ingredients responsible for the efficacy against P. cubensis is lacking.