A detailed linkage map of lettuce was constructed using 53 genetic markers including 41 restriction fragment length polymorphism (RFLP) loci, five downy mildew resistance genes, four isozyme loci and three morphological markers. The genetic markers were distributed into nine linkage groups and cover 404 cM which may be 25-30% of the lettuce genome. The majority (31 of 34) of the RFLP probes det...

ABSTRACT The epidemiology of lettuce downy mildew has been investigated extensively in coastal California. However, the spatial patterns of the disease and the distance that Bremia lactucae spores can be transported have not been determined. During 1995 to 1998, we conducted several field- and valley-scale surveys to determine spatial patterns of this disease in the Salinas valley. Geostatistic...

Mitochondrially encoded cox2 sequences were used to infer evolutionary relationships of downy mildew and white rust taxa in a data set of 36 peronosporomycete isolates. The data set of 599 aligned nucleotides was analysed using neighbor joining, maximum parsimony, and maximum likelihood. These phylogenetic analyses did not infer separate monophyletic orders for the Pythiales versus downy mildew...

ABSTRACT Resistance to Striga hermonthica in 274 wild Pennisetum glaucum subsp. monodii and stenostachyum accessions was evaluated at Samanko, Mali in 1997 and 1998, and at Cinzana, Mali and Sadoré, Niger in 1998. Data recorded included number of striga plants per plot at least three times during the season, date of striga emergence, number of Pennisetum plants, Pennisetum anthesis date, and do...

Downy mildew is caused by the oomycete Plasmopara viticola and is one of the most serious diseases of grapevine. The beneficial microorganism Trichoderma harzianum T39 (T39) has previously been shown to induce plant-mediated resistance and to reduce the severity of downy mildew in susceptible grapevines. In order to better understand the cellular processes associated with T39-induced resistance...

Protein derivatives and carbohydrates can stimulate plant growth, increase stress tolerance, and activate plant defense mechanisms. However, these molecules can also act as a nutritional substrate for microbial communities living on the plant phyllosphere and possibly affect their biocontrol activity against pathogens. We investigated the mechanisms of action of a protein derivative (nutrient b...

The research aims to model wine producer behavior and to assess the effectiveness of policies to reduce pesticide use in winegrape growing. We model the decision of a producer maximizing expected income under constraints and phytosanitary risk, considering the impacts of different strategies targeting downy mildew, the main grape disease in European Atlantic vineyards. The VINEPA model is a mul...

Sunflower (Helianthus annuus L.) is one of the most important vegetable oil sources in world and our country. The preference for sunflower consumption increases importance sunflowers Rust, downy mildew, Verticillium wilt, Sclerotinia stalk head rot, charcoal blight, leaf spot are some diseases commonly seen sunflowers. In years, depending on climatic conditions, Downy mildew (Plasmopara halsted...

In order to realize automatic disease diagnosis and provide related information for disease prediction and control timely and accurately, the identification and diagnosis of grape downy mildew and grape powdery mildew was conducted based on image recognition technologies. The method based on K_means clustering algorithm was used to implement unsupervised segmentation of the disease images. Fift...

LAL, S., S. C. SAXENA, and R. N. UPADHYAY. 1980. Control of brown stripe downy mildew of maize by metalaxyl. Plant Disease 64:874-876. Seed treatment with metalaxyl at 4 g/ kg controlled brown stripe downy mildew (Sclerophthora rayssiae var. zeae) of maize up to 30 days after planting. When combined with seed treatment, one foliar application of metalaxyl (225 ppm) on the 30th day after plantin...