溫濕度對百合白絹病發生之影響

Effects of Temperature and Moisture on the Occurrence of Lily Southern Blight Caused by Sclerotium rolfsii Sacc.

謝廷芳(T. F. Hsieh) ； 杜金池(C. C. Tu) ； 蔡武雄(W. H. Tsai)

《中華農業研究》 39卷4期 (1990/12) Pp. 315-324

https://doi.org/10.29951/JARC.199012.0007

摘要

百合白絹病係由Sclertium rolfsii Sacc.所引起，以人工接種風乾菌核於種球周圍1公分內之土壤，得知5粒菌核（接種源密度爲2.6個菌核／100立方公分土壤）即可致使百合出現黃化病徵，且被害度會隨著菌核接種數目的增加而增加。一般而言，自接種之日起二個星期內病害即可發生。八種受測試之百合品種中以Polyanna和Cote d'Azur較罹病，被害度分別爲0.56和0.50。百合全生長時期皆可遭受白絹病之爲害，被害度以露蕾期最高。本菌菌核於土壤平板上適合發芽溫度爲20~28℃，如先經乾燥低溫(20℃)處理三天再加水並移置於28℃下可提高發芽率。百合先經20℃處理一星期再移置於28℃下，最易遭受白絹病之爲害，與28℃之處理呈顯著差異(ρ=0.05)。最適合本菌菌核發芽和菌絲生長之水分潛勢爲－1~-10bars，低於－20bars時會降低其發芽率和生長速率。遞減土壤含水量會促進病害之發生，在土壤含水量先30%(W/W)後15%變化處理時被害程度爲0.75，與15%含水量處理者呈顯著差異(ρ=0.05)。當由20℃提高至28℃時，無論土壤含水量爲15或30%，在接種四星期後，百合被害度均達0.81，唯一不同只是在15%土壤含水量下病勢進展較快速。

關鍵字

百合 ； 白絹病 ； 接種源密度 ； 溫度 ； 土壤濕度 ； 被害度

並列摘要

Lily southern blight was caused by Scierotium rolfsii Sacc. When 5 dried sclerotia (Inoculum density about 2.6 sclerotia per 100cm^3 of soil) were inoculated into soil around the bulb of lily within 1cm, the yellowing symptom could appear obviously within 2 weeks. Moreover, the disease severity increased gradually with the increasing number of inoculating sclerotia. Eight varieties of lily tested for resistance to S. rolfsii (Sr029) indicated that all of them could be infested in 2 weeks after inoculation. Varieties Polyanna and Cote d'Azur of Lilium asiatic hybrid group were more susceptible than others. All of the growth stages of lily were susceptible to the pathogen especially at the visible bud stage. On soil plate, the maximum sclerotial germination occurred at 20-28℃. The percentage of germination was increased when the sclerotia were incubated under drying condition for 3 days at 20℃ and then remoistened and placed at 28℃. Consistently, the greater disease severity was obtained when the lily plants were transferred into the 28℃ condition after 1 week of incubation under 20℃. In general, the best solute water potential for sclerotial germination and mycelial growth was between -1 and -10 bars. However, with decreasing of solute water potential from -10 to -50 bars, the percentage of germination and growth rate were decreased. Changing soil moisture promoted disease severity; the disease severity was about 0.75 when soil moisture was adjusted to about 30% moisture holding capacity (MHC) and then progressively dried by natural way down to 15% MHC. Moreover, under the condition that tested plants were tranferred from 20 to 28℃, the disease severity of both soil moisture treatments (15 and 30% MHC) was up to 0.81 after 4 weeks of inoculation, however, it showed that the disease development was faster at 15% MHC.

並列關鍵字

lily ； Sclerotium rolfsii Sacc ； inoculum density ； temperature ； soil moisture ； disease severity