Diseases

Cucumber leaf spots

Cucumis sativus L.

A group of infectious cucumber diseases including angular leaf spot, corynespora leaf spot, and alternaria leaf spot, which differ in etiology and symptoms. They are characterized by the formation of necrotic spots of various shapes and structures on the leaf blade.

In the reference 244 varieties crop Cucumber, where this is mentioned in the description.

Angular leaf spot is caused by the bacterium Pseudomonas amygdali pv. lachrymans and manifests as vein-delimited spots, which, under high humidity, exude a bacterial ooze that forms a white crust. Genetic resistance to this pathogen is associated with the gBALS4.1 and gBALS6.1 loci, as well as genes involved in salicylic acid metabolism.

Corynespora leaf spot, caused by the fungus Corynespora cassiicola, is characterized by target-like spots with a gray-white center that can coalesce and cause defoliation. Resistance is provided by the cca-3 gene on chromosome 6, which encodes the CC-NB-ARC protein, as well as the Tls5.1 and Tls5.2 QTLs on chromosome 5 and the CsMLO4 protein.

Alternaria leaf spot, caused by fungi of the genus Alternaria, manifests as brown spots with concentric rings and a chlorotic halo. Scab, caused by Cladosporium cucumerinum, primarily affects fruits in the form of water-soaked spots and skin cracking, appearing less frequently on leaves.

General information about the subject — on the page Leaf spot diseases.

Sources8

Varieties of Cucumber mentioned in the description

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.