Phytophthora oleae, a new root pathogen of wild olives

• DOI: 10.1111/ppa.13024
• Publication Date: 2019-03-27T23:47:38Z
• Authors: M. González; A. Pérez‐Sierra; M. E. Sánchez
• Keywords: Olea; Olive trees; Root rot

Wild olive ( Olea europaea subsp. var. sylvestris ) is an important component of Mediterranean forests and a key genetic source for improvement programmes. Since 2009, severe decline caused by Phytophthora cryptogea P. megasperma has been detected in protected wild forest high ecological value (Dehesa de Abajo, Seville, Spain). In this natural forest, sampling roots soil was carried out on 25 olives with symptoms 2014 2015. Apart from the already known A1 , third species consistently isolated rootlets symptoms. These isolates conformed morphologically newly described oleae were confirmed analysis their ITS regions cox1 sequences. Temperature–growth relationships showed maximum growth at 19.9 °C carrot agar medium, making it lowest temperature infecting roots. Pathogenicity 1‐year‐old healthy seedlings similar to previously pathogenic phytophthoras. As requirements are quite different, three may be active against different seasons. However, prevalence recent years could due its introduction as new invasive pathogen. The probable nature together increasing rain episodes concentrated short periods frequent southern Spain, would allow outbreak infections forests, also put cultivated orchards risk.