Microdochium bolleyi. Effects on turf.

The fungus Microdochium bolleyi has been the subject of several research studies. Initially thought to be a non-pathogenic endophytic agent and a weak parasite, recent studies have identified it as a pathogen, particularly in turfgrasses.

Taxonomic classification

The taxonomic classification of Microdochium bolleyi is based on their position within the fungal phylogenetic tree, which is determined by analysis of ribosomal DNA (rDNA) sequences specifically of the internal transcribed spacer region (ITS). According to the information provided, M. bolleyi has a different sequence from other species such as M. nivale y M. oryzaeand is distantly related to Microdochium phragmitis Syd.

The taxonomic classification of M. bolleyi has evolved over time. Originally described as Gloeosporium bolleyi by Sprague in 1948, has been reclassified several times. Von Arx reclassified it as Aureobasidium bolleyi in 1982, and later as Idriella bolleyi. The current classification of M. bolleyi is due to De Hoog and Hermanides-Nijhof, who placed it in the genus Microdochium, order Hypocreales, division Ascomycota.

Within this genre, M. bolleyi is considered a distinct species with unique morphological and cultural characteristics, such as the formation of dark chylamidospores and thick-walled brown chlamydospores, which are consistent with previous observations.

Effects and its association with Anthracnose

Symptoms of the disease caused by Microdochium bolleyi in turfgrass mainly appear on the leaves and crowns of turfgrasses. Affected leaves turn yellow and then turn brown or reddish-brown without distinctive spots. There is no clear line separating healthy and diseased tissues on an affected plant. In severe cases, diseased plants form patches.

In Korea, symptomatic leaves were observed on a golf course showing damage similar to basal rot caused by Microdochium species. Although there are no previous records of these species causing basal rots, the study confirmed the presence of M. bolleyi and described the symptoms of rot on hypocotyls on different types of turf.

Anthracnose on lawns, usually caused by the fungus Colletotrichum graminicolais associated with M. bolleyi in some areas. All grasses are susceptible to anthracnose, but the disease can be particularly severe in certain species such as Poa pratensis y Agrostis. Symptoms include scattered chlorosis or irregular chlorotic spots which can vary in size. As the disease progresses, infected leaves develop reddish-brown spots, often surrounded by a yellow halo, and may spread over the entire leaf. Anthracnose may also attack crowns and roots, causing basal rot.

Disease control includes cultural practices such as maintaining density and turf nutritionimprove drainage and air circulation in the soil, avoid soil erosion, prevent irrigation frequent and superficial, reduce thatch levels and, where necessary, use preventive systemic fungicides.

Controversy over strain-specific pathogenicity

The controversy surrounding the pathogenicity of Microdochium bolleyi according to strain is based on contradictory findings in the scientific literature. Initially, it was believed that M. bolleyi was a non-pathogenic endophytic agent or a weak parasite, as suggested by some studies (Mandyam, Loughin and Jumpponen, 2010; Kirk and Deacon, 1987). However, more recent research has classified M. bolleyi as a pathogen, especially in turfgrasses (Braun, 1995; Hong et al., 2008).

In the aforementioned study, it was found that the majority of the isolates of M. bolleyi in Turkey were not pathogenic, but those that were pathogenic showed high virulence, particularly in grass, wheat and barley. This indicates that the pathogenicity of M. bolleyi can vary significantly between different strains and that some may be more virulent than others.

In addition, the study noted that the isolates of M. bolleyi from Kocaeli province, which has a temperate coastal climate, were more virulent than those from other provinces, suggesting better adaptation to humid, temperate climates. This is consistent with the idea that the pathogenicity of M. bolleyi may be influenced by environmental factors and that certain strains may have evolved to be more pathogenic under specific conditions.

Detection

The most effective way to diagnose Microdochium bolleyi are the analyses of qPCR fast where we can identify dozens of diseases with a single sample.

Do you need to efficiently diagnose the incidence of M. bolleyi or your potential condition? Contact Tiloom at info@tiloom.com and in less than 48 hours you will have the answer through a qPCR diagnostic analysis of the most common grass diseases.

Accurate knowledge of potential diseases affecting your lawn will enable you to act preventively and manage it in the most effective way. sustainable and efficient possible.

• Penn State University (PSU). 2013. Anthracnose Foliar Blight and Basal Rot. Accessed Sunday 15, December 2013.
• Smiley, R.S. 1983. Compendium of Turfgrass Diseases, APS Press, The American Phytopathological Society, Minnesota, USA.
• Vargas, J.M.1994. Management of Turfgrass Diseases, Lewis Publishers, Boca Raton, Florida.
• Ünal F. Phylogenetic analysis of Microdochium spp. associated with turfgrass and their pathogenicity in cereals.
• Hong SK, Kim WG, Choi HW, Lee SY. Identification of Microdochium bolleyi Associated with Basal Rot of Creeping Bent Grass in Korea. Mycobiology. 2008 Jun