一、叶片病害 1.黑痂病(Black crust) 症状此菌在有子座情况下,特别对橡胶,症状非常显著。在叶背上有黑色、圆形、光亮的菌痂,直径为5—10毫米,在病斑的反面产生浅黄色斑点。菌痂可呈圆形,沿着叶脉辐射向外发展或集中在一个或几个同心圆形的斑点上。病斑很多,常常引起落叶。 First, leaf disease 1. Black crust symptoms (Black crust) Symptoms of bacteria in the case of a child, especially on the rubber, the symptoms are very significant. On the back of the leaves are black, round, bright callus, 5-10 mm in diameter, producing a yellowish blotch on the opposite side of the lesion. The callus may be rounded, radiating outward along the veins or concentrating on one or more concentric spots. Many lesions, often causing deciduous.