Mad cow" disease is an infectious disease caused by prions that affect the brains of cattle. The actual name of the disease is bovine spongiform encephalopathy (BSE), a name that refers to the changes seen in brain tissue of affected cows.
Several pathogens, including viruses, viroids, and phytoplasma, cause serious diseases in chrysanthemums. So far, ten species including Chrysanthemum stunt viroid (CSVd) and Potato spindle tuber viroid (PSTVd) are members of the genus Pospiviroid.
Mycoplasma is a genus of the bacteria which infects plants, animals and humans causing diseases. Some of the common diseases in plants caused by Mycoplasma are citrus greening, sandal spike and grassy shoot in sugarcane plant. In citrus greening, the fruits are small and green in colour. In sandal spike, there is a reduction in leaf size and formation of rosette spike. In the grassy shoot, there is an overgrowth of leaves and there is no growth of cane.
Rice tungro disease is caused by the combination of two viruses, which are transmitted by leafhoppers. It causes leaf discoloration, stunted growth, reduced tiller numbers and sterile or partly filled grains. Tungro infects cultivated rice, some wild rice relatives and other grassy weeds commonly found in rice paddies.