Co-infection of Diaporthe foeniculina and Biscogniauxia rosacearum in Myrtus communis in Tunisia: influence of temperature and rainfall

Common myrtle (Myrtus communis), a Mediterranean shrub species widely distributed within the forest of Northwest Tunisia, holds a crucial role in medicine as a vital resource for the local community and in maintaining ecosystem health and biodiversity. This study investigated the phytosanitary status of M. communis in Tunisian forests from a phytopathological perspective, exploring weather-related pathogen correlations. The study exhibited a month-dependent occurrence, with a significant difference in isolation frequency (IF%) between March and May (D. foeniculina P < 0.001; B.rosacearum P < 0.005), predominating in March for both fungal species. Moreover, a significant negative correlation was revealed between isolation frequency and temperature (P =-0.724), while a significant positive correlation was noted between isolation frequency and rainfall (D. foeniculina P = 0.995; B.rosacearum P = 0.981) for both fungal species. Our results underscore the effect of weather conditions on pathogen infection. This highlights the necessity of incorporating these considerations into the management strategies aimed at preserving myrtle, given its ecological and industrial importance. This finding is the first record of Diaporthe foeniculina and Biscogniauxia rosacearum causing leaf disease in Myrtus communis in the North Africa.