Minuscule black bugs on houseplants

(Question)

Basil plants had small black bugs on them.  The plants are done and have been discarded.  Should I throw the soil out?  I also have those same black bugs on a sweet potato vine.  I did spray it the other day but bugs are still there.  I will probably have to throw it out as well.  Should I throw that soil out too?

(Answer)

Anytime there is an infestation, and treatment has been unsuccessful, it would be best to discard the soil along with the plant in order to minimize any future problems.

This infestation is spider mites and they are very difficult to get rid of.  Some things you can try are:

  • disposal of affected plants including soil
  • isolate the plant and spray with  horticultural oil or insecticidal soap
  • a hard spray of water including under the leaves
  • introduce predators such as ladybugs or predatory mites

These treatments are not always successful and more often, plants are sacrificed and replaced with healthy specimens.