|Title:||台灣莧菜疫病之研究與病害防治||Other Titles:||Studies on Phytophthora Disease of Amaranth and Its Control in Taiwan||Authors:||安寶貞
|Issue Date:||Sep-2015||Publisher:||農業試驗所||Related Publication(s):||農業試驗所特刊第184號||Start page/Pages:||13-22||Source:||台灣新浮現之重要作物病害及其防治研討會專刊||Conference:||台灣新浮現之重要作物病害及其防治研討會
Proceedings of the Symposium on Important New Emerging Crop Diseases Taiwan and Their Controls
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，該病害在國內外並未報導過，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；病菌在8-32℃下可生長，在12-28℃下可誘發病害，最適生長與發病溫度均為20-24℃；並且在所有接種發病的罹病組織內形成大量卵胞子，可為殘存器官；病菌在病土中殘存期可長達2.5年以上，均可再誘發病害；含病菌之土壤中經60℃10分鐘便完全死亡。該菌對滅達樂的抗性為中等，在添加100 ppm的培養基上的生長率為對照處理的26.7-43.6%。進行藥劑防治試驗，供試藥劑包括福賽得(500×)、快得寧(1500×)、亞磷酸(500與1000×) 及達滅芬 (4000×)，結果所有藥劑均有良好的防治效果，但以達滅芬對葉部病害防治效果最佳，次為福賽得、亞磷酸及快得寧；但防治莖基部腐敗時，則以亞磷酸、福賽得較佳，達滅芬次之，快得寧最差。而物理方法將連作土壤蒸汽處理30 min或60 min，均可完全將土攘深度15 cm以內的疫病菌完全消滅，顯著降低疫病的發生。田間灌注1000 ppm 與2000 ppm的亞磷酸三次對莧菜疫病的防治效果甚佳，同時可以防治白銹病，並對下期作之莧菜疫病有良好之防治效果。
In the spring of 2007, a serious disease on amaranth was noticed in several farms in the major amaranth production area in central Taiwan. Abundant oospores were found in the disease tissues. A species of Phytophthora was consistently isolated from disease tissues. Morphological characteristics of this organism did not match any reported Phytophthora species and the organism was named Phytophthora amaranthi. Pathogenicity tests and molecular characterization confirmed the identity of the organism as a new pathogen of amaranth and a new species of Phytophthora. 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 from 59 fields were obtained. The pathogen was with host specificity; it only attacked amaranth species but not any other vegetable crops. In the fields, the Phytophthora attacked root, basal stem and leaf of the host and caused root and basal stem rot, and leaf blight, respectively. The ranges of temperatures for supporting pathogen growth were from 8 to 32℃ and for inducing disease from 12 to 28℃, with optimum growth and disease development at 20-24℃. A large number of oospores were formed in all the diseased tissues under all the temperatures suitable for disease development. The pathogen could survive as oospores in the soil for more than 2.5 years. All the isolates were slightly resistant to metalaxyl. They can growth at media amended with 10 ppm chemicals. The effects of chemicals on disease control were evaluated. The test chemicals included neutralized phosphorous acid (NPA), Fosetyl-aluminum, oxine copper and dimethomorph. Resulted showed that the best chemical for control of leaf blight was dimethomorph (4000x), followed by Fosetyl-aluminum (500x) and NPA (500 and 1000x), oxine copper was the worst (1500×). While for inhibition of root and basal stem rot in the green house and field studies, NPA (100 & 200x) and Fosetyl-aluminum (200x) were the best. The soil disinfection with steam for 30 minutes or 60 minutes can completely kill the pathogen in the soil depth of 20 cm and significantly reduced the disease incidence of seedling dumping-off and Phytophthora basal stem root. Meanwhile the effect of soil steaming on suppression of Phytophthora disease was better than the Pythium diseases. Result of field study showed that soil drenching with 1000 ppm and 2000 ppm NPA for 3 times could effectively inhibit Phytophthora disease as well as white rust disease of amaranth in the field, meanwhile the control effect of phosphorous acid could last to next plantation.
|Appears in Collections:||植物病理組|
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