The first identification of Rhizoctonia was made in 1914 by C. D. Piper, director of the USGA, and the disease was called “Brown Patch”.
These fungi usually survive naturally in all soils and are maintained from year to year, in the form of bulblets in the thatch. These bulblets are very resistant to heat, cold, drought or fungicides, so once germinated they can cause infection to the grass growing around them.
But there are several species of Rhizoctonia causing diseases in different turfgrasses, so we can find Rhizoctonia solani, R. zeae, R. oryzae, R. cerealis, R. AG-Q causing different diseases, in addition to the existence of other non-pathogenic species that create mutualistic relationships.
The smoke spots that appear indicate that the mycelium of the fungus is very active.
Rhizoctonia spp is a disease that produces different symptoms in the different cespitose species. Its correct identification is difficult and requires molecular techniques. It is easy to confuse with other diseases. It often occurs in conjunction with other diseases such as Pythium spp.
Leaf and Sheath Spot is a generic name used to describe a disease caused by two fungal species: Rhizoctonia Zeae and Rhizoctonia Oryzae. R. Zeae is frequently seen in Festuca Arundinacea with lesions similar to those of the Brown Patch. In Agrostis, R. Zeae is associated with areas of sick grass with dark gray-brown to orange colorations.
The formation of a “smoke ring” can appear particularly with high relative humidity or when the morning dew is intense, it is indicative that the mycelium of the fungus is very active.
Rhizoctonia cerealis gives rise to winter Yellow Patch or Brown Patch, very common in Poa, Agrostis and Rye grass greens. Its occurrence in greens of C3 varieties takes place when there are large amounts of rainfall or extended periods of high humidity that cause greens continuously wet for more than 48 hours and high Nitrogen content (it can occur between wide temperature ranges, 8-40ºC). The use of wetting agents is advised on a regular basis in agronomic management.
The different species of Rhizoctonia are natural soil inhabitants, but they are only active when the perfect conditions for their development occur, situations where soil temperature rises above 15°C and air temperature exceeds 28°C in well-fertilized turf areas (high nitrogen inputs) and with frequent irrigations.
Thanks to qPCR you can identify the disease affecting your course or pitch.
Nowadays, with fewer and fewer phytosanitary options to fight fungal attacks, we have to favor natural defense mechanisms, increase the beneficial microbial flora, decrease the levels of thatch, carry out cultural tasks that reduce the formation of constant dew, etc…
Know exactly if you are suffering from Pythium you have through its correct identification with qPCR analysis. Contact us at info@tiloom.com and we will collect the necessary samples for you. Make a preventive management in order not to reach limit situations.