What is the meaning of infestation?

Answer 1

The presence of unacceptable numbers of a pest populationis the meaning of 'infestation'. The numbers may be considered too high because of the sheer numbers. They particularly are considered too high because of the damage, danger, discomfort, threat or unattractiveness that the size of the populations may involve.

For example, gardeners may like the presence of ladybugs [of the Coccinellidae family] outside. But they may not like those same numbers indoors. Outside, ladybugs tend not to fall into the 'infestation' category. They're seen as hearty eaters of garden pests.

But indoors, these very same ladybugs well may fall into the 'infestation' category. They still may be beneficial in eating mites [of the Acarina subclass]. But homeowners tend not to like seeing ladybugs mass sheltering behind window hangings.