Botryosphaeria Dieback (Lasiodiplodia viticola): An Imminent Emerging Threat to the Moroccan Vineyards.

A decline of various grapevines (Vitis vinifera L.) in the province of Doukkala in Morocco was observed in 2021. The causal pathogen was identified as Lasiodiplodia viticola based on morphological characteristics and phylogenetic analysis of the internal transcribed region (ITS), the ß-tubulin gene (TUB) and calmodulin (cmdA). Koch's postulates were confirmed by successful re-isolation of L. viticola from plants inoculated with the pathogen under controlled conditions. The disease was shown to be prevalent in Bni Hilal (71.43%), Laamria (60%), and Boulaouane (40%) districts, but was quasi-absent in Lmechrek. To understand the dominance of L. viticola as one of the grapevine trunk pathogens, effects of temperature (10-40 °C) and pH (pH 3-pH 12) on growth and sporulation were investigated. The species were able to grow in a range of temperatures ranging from 15 to 40°C and showed a higher growth rate at 35 °C. The fungus were also characterized by a broad optimum pH ranging between 3-12. This study is the first report dealing with L. viticola associated with grapevine trunk diseases in Morocco. Additional studies are therefore required to understand the high occurrence of this disease in vineyards, which is likely due to climate changes. A good understanding of this complex disease might help to develop a reliable and sustainable preventive control strategy.

A Panoramic View on Grapevine Trunk Diseases Threats: Case of Eutypa Dieback, Botryosphaeria Dieback, and Esca Disease.

Grapevine trunk diseases (GTD) are currently one of the most devastating and challenging diseases in viticulture, leading to considerable yield losses and a remarkable decline in grapevine quality. The identification of the causal agents is the cornerstone of an efficient approach to fighting against fungal diseases in a sustainable, non-chemical manner. This review attempts to describe and expose the symptoms of each pathology related to GTD, the modes of transmission, and the harmfulness of recently reported agents. Special attention was given to new diagnostic tests and technologies, grapevine defense mechanisms, molecular mechanisms of endophytes fungal colonization, and management strategies used to control these threats. The present extended review is, therefore, an updated state-of-the-art report on the progress in the management of vineyards.