Strains of pathogens that mildly harm, but do not kill, the host plant are termed . a. salicylic b. avirulent c. herbivores d. jasmonic e. virulent

Explanation:

1. An avirulent pathogen gains enough access to its host plant to enable it to perpetuate itself  mildly harm  without severely damaging or killing the host plant  

2. Avirulent pathogen Not highly infective or likely to cause disease

3.  Avirulent - not virulent and unable to produce disease.

4.  Infecting  a host plant with a strain of virus  which causing the host only mild disease symptoms and no severe disease ; known as  avirulent strain.