Ureña-Padilla A R, Mitchell D J, Legard D E
University of Florida, Gulf Coast Research and Education Center, 13138 Lewis Gallagher Road, Dover 33527.
University of Florida, Department of Plant Pathology, P.O. Box 110680, Gainesville 32611.
Plant Dis. 2001 Jul;85(7):750-754. doi: 10.1094/PDIS.2001.85.7.750.
The oversummer survival of Colletotrichum gloeosporioides in strawberry crown tissue under field conditions was investigated in 1998 and 1999. Strawberry crowns infected naturally with C. gloeosporioides were placed inside cloth bags containing field soil, buried in the field at 5 or 13 cm, then recovered over 6 months of each year. The recovered crowns were plated onto a Colletotrichum spp. semiselective medium and speciated by colony, spore morphology, and molecular markers with species-specific DNA primers. Pathogenicity of selected isolates was confirmed by greenhouse bioassays on strawberry. Of the 428 isolates of Colletotrichum spp. recovered from buried crowns, 96% were C. gloeosporioides and 4% Colletotrichum acutatum. Following an initial increase in the detection of the fungus, survival of C. gloeosporioides was stable for 2 to 3 weeks, then declined. No Colletotrichum spp. were detected after burial for 56 days in 1998 and 98 days in 1999. Because the time between crop seasons is typically more than 170 days, these data support the hypothesis that inoculum of C. gloeosporioides does not survive in buried plant debris between seasons in Florida and, therefore, oversummering crop debris does not contribute inoculum for epidemics of Colletotrichum crown rot in Florida.
1998年和1999年，对田间条件下草莓冠组织中胶孢炭疽菌的越夏存活情况进行了研究。将自然感染胶孢炭疽菌的草莓冠置于装有田间土壤的布袋中，埋于田间5厘米或13厘米深处，然后在每年的6个月时间内进行回收。将回收的冠组织接种到炭疽菌属半选择性培养基上，并通过菌落、孢子形态以及使用物种特异性DNA引物的分子标记进行物种鉴定。通过在温室中对草莓进行生物测定，确认了所选分离株的致病性。从埋入的冠组织中回收的428株炭疽菌属分离株中，96%为胶孢炭疽菌，4%为尖孢炭疽菌。在最初检测到真菌数量增加之后，胶孢炭疽菌的存活率在2至3周内保持稳定，然后下降。在1998年埋入56天后和1999年埋入98天后，未检测到炭疽菌属。由于作物季节之间的时间通常超过170天，这些数据支持以下假设：在佛罗里达州，胶孢炭疽菌的接种体不会在季节间埋入的植物残体中存活，因此，越夏的作物残体不会为佛罗里达州炭疽菌冠腐病的流行提供接种体。
