Apple Proliferation Phytoplasma (APP): Questions and Answers

What is apple proliferation phytoplasma?

APP (Candidatus Phytoplasma mali ['Ca. P. mali']) is a bacteria-like plant pest of apple trees that affects fruit quality and the overall viability of a tree. This pest is considered to be a quarantine pest by Canada and the United States (U.S).

Does apple proliferation phytoplasma affect the health of humans or animals?

APP is a plant disease that does not affect the health of humans or animals.

What are the symptoms of apple proliferation phytoplasma?

Symptoms include a broom-like appearance of branches, the development of abnormal leaf clusters (leaf rosetting), and reduced fruit size and sweetness. APP decreases overall tree growth and viability.

Where does apple proliferation phytoplasma occur in the world?

APP has been reported from many countries in Europe, including in the Balkans and southern Russia, as well as in Türkiye and Syria.