Diseases

Citrus Phytophthora

Citrus L.

A complex of diseases caused by oomycetes Phytophthora citrophthora, P. nicotianae, and others, affecting roots, root collar bark, and fruits of citrus crops.

In the reference 17 varieties crop Citrus, where this is mentioned in the description.

Phytophthora pathogens affect almost all parts of the plant. Root rot causes the death of feeder roots, leading to chlorosis and dieback of branches. Infection of the root collar and trunk is often accompanied by gummosis, where gum exudes from dark, water-soaked spots on the bark, which can lead to girdling of tissues and tree death. Fruits are affected by brown rot, most frequently in the lower part of the canopy.

Resistance of citrus to Phytophthora is quantitative and polygenic in nature and is determined by the genotype of the rootstock, with the species Poncirus trifoliata possessing high resistance. Specific resistance genes of the R-gene type have not been isolated in citrus. Breeding is aimed at using quantitative trait loci (QTL) and studying transcription factors; however, in variety descriptions, resistance is usually characterized as the general tolerance of the rootstock.

General information about the subject — on the page Late blight.

Sources8

Varieties of Citrus 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.