01624nas a2200145 4500008004100000245009700041210006900138300001200207490000700219520113100226100002101357700002101378700002001399856005901419 2006 eng d00aGrowth and sporulation of Phytophthora ramorum in vitro in response to temperature and light0 aGrowth and sporulation of Phytophthora ramorum in vitro in respo a365-3730 v983 a

Phytophthora ramorum, recently found in the US, is causing concern for hardwood forests and the nursery industry. In an effort to identify some of the environmental limitations to growth and sporulation we undertook a laboratory study of four US and three European (EU) isolates. On V8 media, isolates grew when incubated at 2-28 C and produced chlamydospores at 8-28 C. Sporangia were produced at all temperatures tested: 10-30 C for US isolates and 6-26 C for EU isolates. Optimal temperatures were 16-26 C for growth, 14-26 C for chlamydospore production and 16-22 C for sporangia production. US isolates grew less and produced fewer spores when exposed to increasing doses of near-UV radiation (50-300 {micro}W/cm2) and visible radiation (250-1500 {micro}W/cm2). EU isolates were exposed to 300 {micro}W/cm2 near-UV only, which significantly reduced growth of one of three isolates and had no significant effect on spore production. In our studies P. ramorum tolerated a broad range of temperature and light conditions, which suggests that it is capable of establishment in a wide geographic area.

1 aEnglander, Larry1 aBrowning, Marsha1 aTooley, Paul, W uhttp://www.mycologia.org/cgi/content/abstract/98/3/365