Kerns J P, Tredway L P
Department of Plant Pathology, North Carolina State University, Campus Box 7616, Raleigh, NC 27695.
Plant Dis. 2008 Jun;92(6):862-869. doi: 10.1094/PDIS-92-6-0862.
Symptoms resembling Pythium root dysfunction have been observed on golf course putting greens established with creeping bentgrass across the southeastern United States since 2002. Root isolations from 14 golf courses yielded 59 isolates of Pythium volutum and 16 isolates of Pythium torulosum. Pathogenicity of five isolates of P. volutum, two isolates of P. torulosum, and a combination of the two species was determined by inoculating mature 'A-1' creeping bentgrass plants. Inoculated plants were incubated for 4 weeks at 24/16°C (day/night) to permit root infection, then temperatures were increased to 32/26°C to induce foliar symptoms. No isolates impacted root depth, root mass, or foliar disease severity after 4 weeks at 24/16°C. After increasing the temperature to 32/26°C, isolates of P. volutum induced foliar disease severity ranging from 60 to 84%, whereas isolates of P. torulosum induced only 14 to 35% disease. Isolates of P. volutum consistently reduced root mass and root depth after 4 weeks at 32/26°C, but P. torulosum exhibited no effect. These results demonstrate that P. volutum is a pathogen of mature creeping bentgrass plants. Infections that occur during cool weather reduce the growth and survival of creeping bentgrass roots during hot weather and give rise to foliar symptoms.
自2002年以来，在美国东南部用匍匐翦股颖建植的高尔夫球场果岭上，观察到了类似腐霉菌根功能障碍的症状。从14个高尔夫球场分离根系，得到59株繁茂腐霉菌株和16株瘤状腐霉菌株。通过接种成熟的“A-1”匍匐翦股颖植株，测定了5株繁茂腐霉菌株、2株瘤状腐霉菌株以及这两个物种的组合的致病性。接种后的植株在24/16°C（昼/夜）下培养4周，以使根系感染，然后将温度提高到32/26°C以诱导叶片症状。在24/16°C下培养4周后，没有分离株影响根系深度、根质量或叶片病害严重程度。将温度提高到32/26°C后，繁茂腐霉菌株诱导的叶片病害严重程度为60%至84%，而瘤状腐霉菌株仅诱导14%至35%的病害。在32/26°C下培养4周后，繁茂腐霉菌株持续降低根质量和根系深度，但瘤状腐霉菌株没有影响。这些结果表明，繁茂腐霉是成熟匍匐翦股颖植株的病原体。在凉爽天气期间发生的感染会降低炎热天气期间匍匐翦股颖根系的生长和存活，并引发叶片症状。
