植物病害概念

對於每一類事物都需要有一個明確的概念。植物病理學首先應當根據所累積的全部資料做出植物病害的定義。但是,我們看到英美新近出版的某些植物病理學教科書的著者顯然感到無所適從,索性完全規避對於植物病害做概括的說明。這就是拔特勒等(E.J.Butler& S.G.Jones,1949)所採取的態度。還有一些書說一句廢話來塞責。例如,切斯特爾(K.S.Cheater,1947)說:"植物中的病害就是與其正常結構、功能或經濟價值相違反的任何改變"。威斯特卡特(Westoott,1950)說:"植物病害的最簡單定義是正常的任何偏差"。在很廣泛被採用的一些較老的教科書中常常對於植物病害做冗長的說明,但是完全沒有涉及要點。索羅爾(Paul Sorauer 1914-1920)首先提出的所謂"絕對病害"

PLANT DISEASE CONCEPT

Plant disease, defined dialectically, is the process of contest between plant and a causal agent under the influence of environmental conditions, manifested in the development of injurious effect on the plant. This concept not only facilitates solution of debatable problems on etiology of a definite disease or disease complex in plants without metaphysical error, but also furnishes ideas of possible means for plant disease control.