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：2019-001-0001-016

藏品描述：柑橘的葉片、果實及枝條上皆有潰瘍病的發生。在葉片上，首先出現暗綠色小點，病斑逐漸擴大，中央部呈灰白色凹陷，周圍呈現褐色木栓化之結構；在病斑邊緣常有黃色暈環，罹病葉片漸黃化後落葉。枝條上的病斑和葉片上者甚相似，唯其邊緣缺乏黃暈，呈暗綠色油脂狀。果實上的病斑初期為紅褐色小點，略隆起，隨著病勢進展，病斑逐漸擴大與葉片上病斑相似，唯病斑表面木栓化更甚，外觀也更粗糙，常缺乏鮮明的黃暈。

Citrus canker is a disease affecting Citrus species caused by the bacterium Xanthomonas campestris. Infection causes lesions on the leaves, stems, and fruit of citrus trees, including lime, oranges, and grapefruit. While not harmful to humans, canker significantly affects the vitality of citrus trees, causing leaves and fruit to drop prematurely; a fruit infected with canker is safe to eat, but too unsightly to be sold. The disease, which is believed to have originated in Southeast Asia, is extremely persistent when it becomes established in an area. Citrus groves have been destroyed in attempts to eradicate the disease.