Diseases
Citrullus lanatus (Thunb.) Matsum. & Nakai
A fungal disease of watermelon caused by a complex of pathogens led by Alternaria cucumerina. It manifests as concentric necrotic spots on leaves, leading to their premature death and reduced fruit quality.
In the reference 3 varieties crop Watermelon, where this is mentioned in the description.
The primary causal agent of the disease is the fungus Alternaria cucumerina; however, species such as Alternaria alternata, Alternaria tenuissima, Alternaria gaisen, and Alternaria arborescens also contribute to the pathology. The pathogenicity of these fungi varies depending on the specific isolate, while specific pathotypes or races for this crop have not been classified at this time.
Initial symptoms appear on older leaves in the basal zone as small brown-yellow spots with a halo. As they develop, the spots reach 2 cm in size and acquire a characteristic concentric zonation. Severe infection is accompanied by massive defoliation, which exposes the fruit, makes them susceptible to sunscald, and negatively affects the accumulation of dry matter.
Genetic resistance of watermelon to this disease has not been sufficiently studied, and generally accepted resistance loci or genes have not yet been identified in watermelon breeding. Modern breeding programs focus on searching for sources of immunity among wild Citrullus lanatus species, as domesticated watermelon forms have often lost their natural resistance mechanisms to the pathogen.
General information about the subject — on the page Alternaria blight.
Selection based on the description text, not on official evaluation: these data are absent from registers. For specific variety details, please refer to its profile.
Citrullus lanatus (Thunb.) Matsum. & Nakai · Watermelon
Citrullus lanatus (Thunb.) Matsum. & Nakai · Watermelon
Citrullus lanatus (Thunb.) Matsum. & Nakai · Watermelon