(a) mosaic disease of tobacco :
In this disease leaves get shrinked and become small. The chlorophyll of leaves get destroyed. The factor of this disease is Tobacco Mosaic Virus (TMV).
Control - Affected plants should be burnt.
(b) Bunchy top of banana - This diseases is caused by banana virus. In this disease plants become dwarf and all the leaves get accumulated like a rose on the branch.
Wilt of Potato : It is also known as ring diseases because brown ring is formed on the xylem. The factor of this disease is Pseudomonas solonacearum bacteria. In this disease the conduction system of the plant is affected.
(b) Black Arm of cotton : The factor of this disease is Xanthomonas Bacteria. In this disease a water body (brown) is formed on the leaves.
Bacterial blight of Rice : This disease is caused by Xanthomonas oryzae bacteria. Yellow-greenish spot is seen on both side of leaves. Vascular bundles get blocked due to bacterial growth.
Citrus Canker : The factor of this disease is Xanthomonas citribacteria. It has originated in China. Leaves, branches, fruits all are affected by this disease.
Tundu disease of wheat : The factors of this disease are Corinobacterium titrici bacteria and Enzuina Titriki Nematode. In this disease lower parts of the leaves are faded and turned.
The diseases included in this group are caused by fungi.
» Rust of wheat is a disease caused by fungi Puccinia.