Diseases

Avocado root rot

Persea americana Mill.

A devastating disease caused by the oomycete Phytophthora cinnamomi, which primarily affects small feeder roots and causes systemic decline of the tree.

In the reference 6 varieties crop Avocado, where this is mentioned in the description.

The primary pathogen is the oomycete Phytophthora cinnamomi, although Rosellinia necatrix and Phytopythium helicoides are also encountered. Clonal lineages such as A2, characterized by high phenotypic variability in virulence and growth rate, are identified within pathogen populations, while classical races are not defined.

The disease affects small feeder roots, which turn black, become brittle, and die. Impairment of the root system functions leads to symptoms of water stress: leaf chlorosis, marginal necrosis, canopy thinning, and gradual tree wilting, often accompanied by a temporary flush of small fruits prior to tree death.

No fully immune varieties exist; breeding efforts are aimed at developing partially resistant rootstocks. Resistance correlates with intense regulation of PaNLR gene expression following infection, which allows the plant to more effectively suppress the spread of the pathogen.

General information about the subject — on the page Root rots.

Sources8

Varieties of Avocado 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.