Aphids may be controlled with applications of Diazinon dust or sprays of Sevin or rotenone.
The iris borer is the most serious insect pest. They overwinter as eggs on debris. The larvae enter the leaves when the leaves are 5 to 6 inches high and may pupate in the rhizome.
Thrips rasp the foliage causing russeting and blackening of growth. In older clumps the tops die out and turn brown. These insects can be controlled with rotenone, or Sevin.