Diseases

Downy mildew — New Guinea impatiens

Impatiens New Guinea Group

New Guinea impatiens is a highly resistant species to the pathogen Plasmopara obducens, unlike Impatiens walleriana, and does not exhibit characteristic symptoms of infection.

In the reference 32 varieties crop New Guinea Impatiens, where this is mentioned in the description.

The disease is caused by the oomycete Plasmopara obducens, which possesses high specificity to members of the Impatiens genus. New Guinea impatiens is characterized by species-specific resistance to this pathogen; therefore, classic signs of infection, such as leaf yellowing and curling, the presence of white downy growth, and leaf drop, are not observed.

There is no data in scientific literature regarding the isolation of specific races or pathotypes of Plasmopara obducens capable of overcoming the resistance of New Guinea impatiens. Although specific resistance genes have not been classified, transcriptome research is underway to identify defense mechanisms, and the resistance itself is recognized as a stable species characteristic that cannot be transferred to susceptible species via traditional breeding methods due to genetic differences.

General information about the subject — on the page Downy mildew.

Sources8

Varieties of New Guinea Impatiens 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.