Abstract
In the middle of May 2018, typical red thread disease symptoms were observed on Kentucky bluegrass (Poa pratensis L.) on a golf course, which locates at Yangsan, Gyeongnam province in Korea. Irregular-shaped patched symptoms were observed in both fairway and rough of golf course. The foliar symptom was dried out and faded to straw color and tip of the grass leaves were tangled like thread. Early morning, infected and tangled leaves were covered with the pinkish gelatinous antler-like structure (sclerotinia) as a typical red thread disease symptom. Causal fungal pathogens were isolated from the symptom in Kentucky bluegrass, Cultural characteristic on potato dextrose agar, color of colony was pale pink and conjugated hyphae, sclerotium of irregular shape was pale pink and 3-5 mm diameter in size. The pathogen was identified as Laetisaria fuciformis based on morphological and culture characteristics as well as molecular characteristics. Pathogenicity test was verified on the Kentucky bluegrass by Koch’s postulates. This is the first report of red thread disease occurrence in Kentucky bluegrass by L. fuciformis in Korea.
Figures & Tables
Fig. 1. Symptoms and signs of red thread disease in Kentucky bluegrass. A: Red thread on golf course growing Kentucky bluegrass; B: Antler like structures (sclerotia) growth from blighted leaves; C: connecting leaf blades; D: flocks of pink mycelium on leaf blades.
