The difference between Blight and Scab

Blight as a noun (plant disease):

Any of many plant diseases causing damage to, or the death of, leaves, fruit or other parts.

Blight as a noun:

The bacterium, virus or fungus that causes such a condition.

Blight as a noun (by extension):

Anything that impedes growth or development or spoils any other aspect of life.

Blight as a verb (transitive):

To affect with blight; to blast; to prevent the growth and fertility of.

Blight as a verb (intransitive):

To suffer blight.

Blight as a verb (transitive):

To spoil or ruin (something).

Scab as a noun:

An incrustation over a sore, wound, vesicle, or pustule, formed during healing.

Scab as a noun (colloquial, or, obsolete):

The scabies.

Scab as a noun:

The mange, especially when it appears on sheep.

Scab as a noun:

Any of several different diseases of potatoes producing pits and other damage on their surface, caused by streptomyces bacteria (but formerly believed to be caused by a fungus).

Scab as a noun:

Common scab, a relatively harmless variety of scab (potato disease) caused by .

Scab as a noun (plant disease):

Any one of various more or less destructive fungal diseases that attack cultivated plants, forming dark-colored crustlike spots.

Scab as a noun (founding):

A slight irregular protuberance which defaces the surface of a casting, caused by the breaking away of a part of the mold.

Scab as a noun:

A mean, dirty, paltry fellow.

Scab as a noun (offensive, slang):

A worker who acts against trade union policies, especially a strikebreaker.

Scab as a verb (intransitive):

To become covered by a scab or scabs.

Scab as a verb (intransitive):

To form into scabs and be shed, as damaged or diseased skin.

Scab as a verb (transitive):

To remove part of a surface (from).

Scab as a verb (intransitive):

To act as a strikebreaker.

Scab as a verb (transitive, UK, Australia, NZ, informal):

To beg (for), to cadge or bum.