Title: Plant disease - Transmission | Britannica
Headings: 
Transmission
Control
Some viral and viroid diseases of plants
Diseases caused by bacteria
General characteristics

Content: causes reduction of crop yield

Diseases caused by bacteria
Thousands of bacterial species occur in nature. Many of these perform biochemical processes essential for the continuity of life; for example, bacterial detritivores, or decomposers, feed on nonliving organic matter, recycling it through the ecosystem. There are, however, hundreds of bacterial species that cause diseases in humans, animals, and plants. General characteristics
Bacteria are prokaryotic microorganisms—i.e., single-celled microorganisms in which the nuclear substance is not enclosed in a membrane. There are two major types of bacteria, the eubacteria and the archaebacteria, and they are distinguished by differences in the composition of their cell wall and cytoplasmic membrane and by certain metabolic features. Plant pathogens belong to the eubacteria. The eubacteria can be divided into three groups: gram-negative bacteria, gram-positive bacteria, and the mycoplasmas and spiroplasmas, referred to as mycoplasma-like organisms (MLOs).