Aphids suck plant juices but are easily controlled with applications of Sevin, rotenone or Diazinon dust.
Verbena leaf miner makes blotches along the leaf margins as it mines out the leaves. Pick off and destroy infested leaves. No chemical control is listed.
Greenhouse whitefly infests and feeds on verbena causing bronzed leaves. Some varieties are more susceptible than others. Infested garden plants should not be brought into the house for winter bloom.
Thrips rasp the leaf tissue then suck the plant juices. They will be controlled with Sevin or rotenone.
Mites cause bronzing of the foliage and loss of green color.