Paecilomyces maximus: a new threat to cherry trees in Turkey

08 Oct 2024
711

In August 2022, a new pathogen affecting cherry trees was reported in Turkey. The fungus Paecilomyces maximus, already known in other parts of the world, causes dieback and canker in cherry trees, which is one of Turkey's most important crops. Therefore, controlling this pathogen will be crucial to avoid significant production losses.

The first case of infection was detected in an orchard located in the Çınar region, in Diyarbakır province. Symptoms observed in the plants included branch wilting, wood canker, discoloration of the bark and internal parts of the trunk, which eventually led to plant death. The incidence of the disease was estimated at around 5% in the orchard, a figure that, although limited, immediately raised concerns due to the rapid spread and severity of the symptoms.

To precisely identify the responsible pathogen, researchers collected wood samples from infected trees. The samples were superficially disinfected and cultured on potato dextrose agar (PDA) to observe the fungus's growth. The colonies initially developed in white but over time turned yellow or brown, indicating the presence of Paecilomyces maximus.

Microscopic observation revealed the presence of branched conidiophores, with phialides arranged in divergent whorls and ellipsoidal or cylindrical conidia with truncated ends. These morphological characteristics were consistent with those reported in the literature for P. maximus.

However, to definitively confirm the identity of the pathogen, a molecular analysis was performed. Sequencing of the ITS region and the beta-tubulin gene showed a very high degree of similarity (99.6% for ITS and 100% for beta-tubulin) with a known strain of Paecilomyces maximus, thus confirming the fungus's identification.

To further verify the pathogenic role of P. maximus in cherry trees, experimental tests were carried out following Koch's postulates. Branch segments, previously wounded, were inoculated with the fungus grown in the laboratory.

After five weeks of incubation under controlled conditions, brown necrotic lesions appeared on the inoculated branches, while control branches, treated with sterile agar, showed no symptoms. This experiment confirmed that Paecilomyces maximus is indeed responsible for the dieback and canker observed in cherry trees in Diyarbakır.

In conclusion, the discovery of Paecilomyces maximus on cherry trees in Turkey highlights the importance of early diagnosis and collaboration to effectively address new phyto-pathological threats. Further research will be necessary to develop effective and sustainable protocols and solutions to protect cherry trees, one of Turkey’s most vital crops.

Source: Ozan, G. N., Çaplık, D., & Bayraktar, H. (2024). First report of Paecilomyces maximus causing dieback on cherry in Türkiye. Journal of Plant Pathology, 1-2. https://doi-org/10.1007/s42161-024-01717-w.
Image: IPM Images

Andrea Giovannini
University of Bologna (IT)


Cherry Times - All rights reserved

What to read next

Pre-harvest γ-aminobutyric acid helps maintain quality during storage

Post-harvest​

30 May 2024

γ-aminobutyric acid regulates numerous physiological processes in plants. The University of Alicante monitored for two years the effects of foliar sprays of GABA at different concentrations at critical stages of fruit development in three sweet cherry cultivars.

Smart greenhouses and sustainability: the future of cultivation in Xin'an (China)

Planting systems

19 Aug 2024

The success of these intelligent greenhouses lies in their sophisticated monitoring and control systems. A large screen in the control room displays real-time data on temperature, humidity, light and carbon dioxide levels inside the greenhouse.

In evidenza

Surface pitting in cherries: Czech Republic study on quality and storage strategies

Post-harvest​

09 Sep 2025

A three-year study in the Czech Republic on 35 cherry genotypes shows how firmness, genotype and storage conditions affect surface pitting resistance. Results confirm the key role of ULO storage and preventive treatments to safeguard cherry quality and shelf life.

New methods in Poland to speed up sour cherry seed germination

Breeding

09 Sep 2025

A study in Skierniewice, Poland, tested innovative methods to enhance sour cherry seed germination. Seed coat removal combined with cold stratification produced stronger seedlings faster, cutting time and costs while boosting breeding efficiency and genetic progress.

Tag Popolari