作者：曾惠中

類別：圖書文獻類 - 手稿

材質：紙質

年代：1969~1969

尺寸：長:24.6 x 寬:20.5 (cm)

藏品來源：曾惠中捐贈

登錄號：2019-001-0001-046

藏品描述：本病係藉白色粉狀物中之分生孢子傳播，當溫濕度適合時，分生孢子很快長出發芽管而侵入菸葉角質層和表皮細胞，數日後菌絲便產生分生孢子梗及分生孢子再傳播感染。初期感染大多數以老葉開始，在葉面出現淡色污斑，後漸擴大，表面長滿白粉狀孢子，病斑週緣逐漸變黃，而呈枯褐色，通常菸草下位葉先出現病徵，漸次向上位葉蔓延。

The causal fungus Erysiphe cichoracearum is ecotophytic and it produces much mycelia, conidiophores and conidia. Conidia invade the tobacco leaves. Initially the disease appears as small, white isolated patches on the upper surface of the leaves. Later, it spreads fast and covers the entire lamina. The disease initially appears on the lower leaves and as disease advances, the rest of the leaves are also infected and sometimes powdery growth can be seen on the stem also. The affected leaves turn to brown and wither and show scorched appearance. The severe infection leads to defoliation and reduction in quantity and quality of the curable leaves.