The Preliminary Study Of Turfgrass Fungal Diseases In Golf Courses Of Hainan Province

Golf sport has become more and more popular in recent 20 years in China. However, there are only few researches about the plant disease in golf course although it is the main limited factors of the golf course development. In the present study, the fungal disease survey were carried out in golf courses established with hybrid bermudagrass (Cynodon dactylon×C. transvalensis), seashore paspalum (Paspalum vaginatum) and zoysia grass (Zoysia spp.) from 2011 to 2014 in Haikou City. The further epidemiology were analysis and the major detected turf grass diseases were identified with traditional morphology and molecular techniques through experiment analysis, green house and field trial from 2011 to 2014. Turfgrass diseases happened in golf courses of Hainan Province and the epidemiology of common diseases in Haikou City were surveyed. The results were summarized as follows:1. There were total 20 species pathogens included in 16 genera which leaded to 15 diseases in the 3 studied warm-season turfgrass in golf courses of Hainnan Province. In which, there were 16 species pathogens included in 14 genera leaded to 13 diseases in hybrid bermudagrass,11 species pathogens included in 10 genera leaded to 9 diseases in seashore paspalum and 13 species pathogens included in 11 genera leaded to 10 diseases in zoysia grass. There were 5 popular diseases including red thread (Lartisaria fuciformis), dollar spot (Sclerotinia homoeocarpa), Fusarium disease (Fusarium spp.), Rhizoctonia disease (Rhizoctonia spp.) and fair ring (Marasmius spp. and Lycoperdon spp.) occurred in all 3 studied turfgrass. There were 7 disease including tar spot (Phyllachora graminis), pink patch (Limonomyces roseipellis), take all (Gaeumannomyces graminis var. graminis), rusts (Puccinia spp.), anthracnose (Colletotrichum spp.), Nigrospora disease (Nigrospora sphaerica) and Curvularia disease (Curvularia spp.) occurred in 2 of 3 studied turfgrass. Besides, there were 3 specific disease only occurred in 1 host including Bipolaris disease (Bipolaris peregianensis) of hybrid bermudagrass, leaf sprase patch of seashore paspalum and Septoria leaf spot (Septoria nodorum) of zoysia grass.2. Red thread of seashore paspalum occurred throughout the year and was especially popular in Spring (March to May) and Autumn (September to November). There were 2 disease peaks in April with 13.5% and October with 8.9%. Dollar spot of seashore paspalum occurred mainly from October to next April with the peak of 15.6% from later February to early April. Bipolaris disease, Fusarium disease and leaf sprase patch occurred from December to next March with the peak of 20.2%, 48% and 24%, respectively, in middle of February.3. The pathogens of red thread and pink patch were firstly identified as Laetisaria fuciformis and Limonomyces roseipellis in China, respectively. The optimal conditions for hyphal growth of L. fuciformis and Li. roseipellis were 12 h light, 25～28℃ or 28℃, pH 6. The optimal carbon and nitrogen sources for these 2 pathogens were soluble starch and L-glutamine, respectively. The optimal medium for L. fuciformis was Oatmeal agar (OMA) and that for Li. roseipellis was Potato dextrose agar (PDA) or Potato sucrose agar (PSA). The diniconazole had the highest inhibitory effects on L. fuciformis and Li. roseipellis in all 14 tested fungicides with EC50 at 0.113 mg/L and 0.282 mg/L, respectively.4. A new pathogenic specie causing leaf sparse patch on seashore paspalum was identified and named as Microdochium paspali W. Zhang, Z.B. Nan,& M. J. Hu, sp. nov.. The optimal conditions for M. paspali hyphal growth were 12 h light, 25-28℃, pH 6. The optimal carbon sources were cellobiose or lactose and the optimal nitrogen source was apeptone. The optimal medium for M. paspali was Seashore paspalum decoction agar (SPDA). The nested PCR with a pair of designed species-specific primers MpEF4F/MpEF4R combined with EFMspF/EFMspR primers can amplify specific fragment from 5×10-4ng genomic DNA which had 100 times sensitivity of conventional PCR and can be applied to detect M. paspali from infected tissues.5. The host range tests suggested the M. paspali could infect 27 cultivars in 9 species turfgrasses including Cynodon dactylon, Paspalum vaginatum, Paspalum natatum, Lolium multiflorum, Zoysia japonica, Buchloe dactyloides, Festuca arundinacea, Agrostis palustris, Poa pratensis. However, it could not infect 2 cultivars of Trifolium repens. After inoculation with M. paspali, the density, color, cover degree, uniformity of seashore paspalum decreased by 50.3%,62.5%,72.0%,75.8%, respectively, compared with the control. The maximum and the minimum of Malondialdehyde (MDA) concentration in host appeared on 3 and 9 days after inoculation, respectively. The activities of Superoxide dismutase (SOD), Peroxidase (POD), Phenylalnine ammonialyase (PAL), Polyphenol oxidase (PPO) and Catalase (CAT) increased in the early period and reached the maximum with 147.3%-342.1% of control, then decreased and reached the minimum with 46.4%-141.0% of control after 9 days inoculation. Ten percentage difenoconazole were applied 2,4,6, or 8 days before inoculation which provided 100% protection. The combined fungicide of 12.5% difenoconazole·20% azoxystrobin provided 100 protection if applied at 24 h or 48 h after inoculation.