Which statement is TRUE regarding common sources of viral disease in plants?

Which statement is TRUE regarding common sources of viral disease in plants?

• A. Viruses are spread from one plant to another by insect or nematode vectors
• B. Plant becomes waterlogged due to clogged drainage ditches
• C. Weeds
• D. Alfalfa leaves show chewing damage

Answer: (A)

Viral diseases in plants spread mainly through living carriers that move the virus from an infected plant to healthy ones. The most common spread is by insect vectors such as aphids, whiteflies, and leafhoppers, which acquire the virus while feeding and then transmit it to other plants. Some viruses can also be transmitted by nematodes that feed on plant tissues, providing another route for spread. This vector-based transmission is the typical way viruses move through crops, rather than by waterlogged soil or bare plant tissue. The other statements don’t describe how viruses are usually moved: waterlogging is a soil/air- or moisture-related stress, not a mechanism for virus spread; weeds can act as reservoirs but the option by itself isn’t describing the spread mechanism; and chewing damage on alfalfa is a sign of insect feeding or other damage, not a viral transmission route.

Viral diseases in plants spread mainly through living carriers that move the virus from an infected plant to healthy ones. The most common spread is by insect vectors such as aphids, whiteflies, and leafhoppers, which acquire the virus while feeding and then transmit it to other plants. Some viruses can also be transmitted by nematodes that feed on plant tissues, providing another route for spread. This vector-based transmission is the typical way viruses move through crops, rather than by waterlogged soil or bare plant tissue.

The other statements don’t describe how viruses are usually moved: waterlogging is a soil/air- or moisture-related stress, not a mechanism for virus spread; weeds can act as reservoirs but the option by itself isn’t describing the spread mechanism; and chewing damage on alfalfa is a sign of insect feeding or other damage, not a viral transmission route.