莧菜疫病菌之生態與病害防治

Ecology and Control of Phytophthora Disease of Amaranth

10.6649/PPB.201512_24(3_4).0006

安寶貞(P. J. Ann)；蔡志濃(J. N. Tsai)；王姻婷(I. T. Wang)；黃晉興(J. H. Huang)；林筑蘋(J. P. Lin)；蔡惠玲(H. L. Tsai)；王三太(S. T. Wang)；楊智凱(C. K. Yang)

莧菜 ； 生態 ； 病害防治 ； 亞磷酸 ； Amaranth ； Phytophthora amaranthi ； ecology ； disease control ； Phosphorous acid

植物病理學會刊

24卷3&4期（2015 / 12 / 01）

241 - 249

繁體中文

2007年春天在雲林縣西螺鎮蔬菜專業區內的多處莧菜園內發現嚴重疫病，發病時間自11月至翌年6月為止，12月至翌年4月發病較為嚴重，對莧菜產業造成嚴重威脅。在當時，該病害在國內外並未曾報導過，為一新病害。2007年1月至2013年12月共採集59處莧菜田的罹病組織，獲得116株莧菜疫病菌，該病菌僅為害莧菜與野莧，不為害其他蔬菜作物，為一新疫病菌，定名為Phytophthora amaranthi。該病原菌在12-32℃下可誘發病害，最適發病溫度均為20℃；病菌在12-28℃下於罹病組織內可產生卵孢子，最適溫度亦為20℃。病原菌在病土中於16-28℃下殘存期可長達2 年以上，均可再誘發病害，且以存活於16℃下誘發之發病率最高。該病原菌存活於深度0-15 cm的土壤中。將含罹病組織之土壤經60℃處理10 min後，病原菌便完全死亡。進行溫室藥劑防治試驗，供試藥劑包括中和亞磷酸水溶液（NPA）、福賽得、快得寧及達滅芬，結果除快得寧外，其餘藥劑均有良好的防治效果；而罹病田間灌注1000 mg/L與2000 mg/L的NPA 3次對莧菜疫病的防治效果甚佳，罹病率分別降低70.9%與76.2%；而平均株高分別增加28.0%與28.5%；平均株重分別增加41.3%與54.0%。

In the spring of 2007, a new Phytophthora disease on amaranth was noticed in several farms in the major amaranth production area at Xiluo, Yulin, in central Taiwan. The disease generally occurred from November to June of the next year with the most severe periods from December to next April. A total of 116 isolates of Phytophthora were collected from 59 fields from 2007 to 2013. The pathogen was only pathogenic to Amaranthus species including A. tricolor and A. viridis, and was a new species of Phytophthora named Phytophthora amaranthi. Result of inoculation study showed that the pathogen caused disease on amaranth from 12 to 32℃ with an optimal temperature of 20℃. It produced oospores in disease tissues from 12 to 28℃ with an optimal temperature of 20℃. The Phytophthora survived in amaranth disease tissues buried in the soil at 16-28℃ for more than 2 years and induced serious disease (56-100%) on amaranth young seedlings. P. amaranthi was detected in the disease soil in soil depth of 0-15 cm and was killed at 60℃for 10 min. The effects of various chemicals on disease control were evaluated. The test chemicals included neutralized phosphorous acid (NPA), Fosetyl-aluminum, oxine copper and dimethomorph. Results showed that all chemicals, except oxine copper, were effective in control of amaranth leaf blight and basal stem rot caused by P. amaranthi. Result of field study showed that soil drenching with 1000 mg/L and 2000 mg/L of NPA for 3 times effectively reduced the Phytophthora disease and increased plant height and weight of amaranth. NPA remained effective in the control of the disease during next planting.