菊花莖腐病防治及健康菊苗育成之初步研究

Preliminary Study on the Control of Basal Stem Rot and Raise Healthy Cuttings of Chrysanthemum

由Rhizoctonia solani Kühn引起之菊苗莖腐病為臺灣夏季培育菊苗時之最嚴重病害。本文報導「植保素一號」〔暫稱；滑石粉內含0.2%萘乙酸（NAA，α-naphthalene acetic acid）及0.1%免賴得（ Benlate，Benomyl）］能促進菊插穗發根及提高成活率，進而增加對病害之抵抗性。插穗先用藥劑如6.5%新阿蘇仁（Neo Asozin）2000倍液，或50%貝芬替（Bavistin）可濕性粉劑1500倍液浸10分鐘，取出待水滴乾後，插穗基端站「植保素一號」粉劑。本處理可促增加根數二倍左右或更多，但對根長無甚影響。由於根數增加，移植後恢復生機較速，尤於夏季及初秋值高溫多濕育苗困難時，仍可育成發根良好之菊苗。若再配合苗床之改進，可保障臺灣夏季健康菊苗之育成。本菌在田間病株上能形成菌核。菌核在水稻田即浸水條件下之生存較旱作時差。倘本菌密度高時，土壤消毒，仍難有效防治本病。因此建議採用流水所經之河川砂為育苗苗床材料。苗床中菊苗生根帶處，添加鋸木屑或稻殼，對移植本田之菊苗，能附著較多苗床材料，對移植後恢復生機較速，似值得推行。「植保素一號」不僅為農民所樂用，對多數草花卉本如吊鐘花、金魚草、康乃馨等及木本花卉如杜鵑、茶、茶花又桑樹苗素亦有保護及促進生根之作用。

In summer, basal stem rot of Chrysanthemum cuttings induced by Rhizoctonia solani, is the most serious disease in Taiwan. Plant Protection Powder NO.1 (tentative name in this report) composing 0.2 per cent NAA (α-naphthalene acetic acid) plus 0.l per. cent Beplate ［50% Benomyl, 1-(Buthyl carbamoyl) -2-benimidazole carbamic acid］ in talc controls the disease and also increases root number of the cuttings. The cuttings are pretreated by soaking in 2000 times dilution of 6.5% Neo Asoain (ammonium salts of ferric methyl arsenic acid) or 1500 times dilution of 50% Bavistin (MBC, Carbendazim, Methyl-2-benzimidazole carbamate) for 10 min. After draining the cutting end is powdered and then planted. Percentage of living cuttings and root length are generally same between treated and nontreated samples but the number of root is usually twice in the treated cuttings. By using sand collected from streaming river bed to make the cutting bed and combined with the above mentioned treatment allow the growers to raise enough and healthy cuttings in Taiwan during summer time. The fungus survive more than a year in the field condition by sclerotium in the soil although less in the paddy field. High propagules make the soil disinfestation impractical to control the disease. Mixing saw dust or rice grain husk in the root zone makes the cuttings carry more cutting bed materials which is speculated to enhance the recovery of the cuttings after transplanting. 'Plant Protection Powder No. 1' is also good to raise healthier cuttings not only for herbaceous plants such as snapdragon, Fuchsia magellanica, carnation but also for woody cuttings such as azalea, camellia and mulberry.