Feng Yan, Dernoeden Peter H
Department of Natural Resource Sciences and Landscape Architecture, University of Maryland, College Park 20742.
Plant Dis. 1999 Jun;83(6):516-520. doi: 10.1094/PDIS.1999.83.6.516.
Putting green samples (n = 109) were inspected for the presence of Pythium oospores in roots of plants from golf courses (n = 39) in Maryland and adjacent states. Twenty-eight Pythium isolates were recovered from creeping bentgrass (Agrostis palustris) (n = 25) and annual bluegrass (Poa annua) (n = 3) plants. Most isolates associated with Pythium-induced root dysfunction were from greens less than 3 years of age and were obtained primarily between March and June, 1995 to 1997. Eight Pythium species (P. aristosporum, P. aphanidermatum, P. catenulatum, P. graminicola, P. torulosum, P. vanterpoolii, P. volutum, and P. ultimum var. ultimum) were isolated from creeping bentgrass and two species (P. graminicola and P. torulosum) were from annual bluegrass. All species, except P. catenulatum, were pathogenic to 'Crenshaw' creeping bentgrass seedlings in postemergence pathogenicity tests. P. aristosporum (n = 3) and P. aphanidermatum (n = 1) were highly aggressive at a low (18°C) and a high temperature (28°C). P. graminicola (n = 1) was low to moderately aggressive. P. torulosum (n = 12) was the most frequently isolated species, but most isolates were either nonpathogenic or caused very little disease. P. aristosporum (n = 3) and P. aphanidermatum (n = 1) were highly aggressive and were associated with rapid growth at 18 and 28°C on cornmeal agar. P. volutum (n = 1) was highly aggressive at 18°C, but was one of slowest growing isolates. Infected roots were generally symptomless, and the number of oospores observed in roots was not always a good indicator of disease or of the aggressiveness of an isolate. Large numbers of oospores of low or even nonpathogenic species may cause dysfunction of creeping bentgrass roots.
对马里兰州及邻近各州高尔夫球场（n = 39）植物根系中的腐霉菌卵孢子存在情况进行了果岭样本（n = 109）检查。从匍匐翦股颖（n = 25）和一年生早熟禾（n = 3）植物中分离出28株腐霉菌株。与腐霉菌引起的根系功能障碍相关的大多数分离株来自年龄小于3年的果岭，主要在1995年至1997年的3月至6月间获得。从匍匐翦股颖中分离出8种腐霉菌（P. aristosporum、P. aphanidermatum、P. catenulatum、P. graminicola、P. torulosum、P. vanterpoolii、P. volutum和终极腐霉终极变种），从一年生早熟禾中分离出2种（P. graminicola和P. torulosum）。在出土后致病性试验中，除P. catenulatum外，所有物种对“克伦肖”匍匐翦股颖幼苗均具有致病性。P. aristosporum（n = 3）和瓜果腐霉（n = 1）在低温（18°C）和高温（28°C）下具有高侵袭性。禾生腐霉（n = 1）侵袭性低至中等。P. torulosum（n = 12）是最常分离出的物种，但大多数分离株要么无致病性，要么致病力很弱。P. aristosporum（n = 3）和瓜果腐霉（n = 1）具有高侵袭性，且在玉米粉琼脂上于18°C和28°C下生长迅速。P. volutum（n = 1）在18°C时具有高侵袭性，但却是生长最慢的分离株之一。受感染的根系通常无症状，且在根系中观察到的卵孢子数量并不总是疾病或分离株侵袭性的良好指标。大量低致病性甚至无致病性物种的卵孢子可能导致匍匐翦股颖根系功能障碍。
