Spider mites can become the pest of almost any plant during dry weather. Normal rains help keep them in check; hot dry weather can cause major outbreaks.  Light yellow spotting (stippling) on the leaves is the main symptom.  Tissue may appear sand blasted and will dry up and die.  When their numbers are high, spider mites may also make webbing.   Most insecticides are not effective so special products called miticides can be used.