Good culture often eliminates many problems. Compared to many plants Iris are relatively trouble free but under certain conditions you may see the following problems: Related links......Cultivation
Irises suffer less from diseases and pests than most other garden plants under normal conditions. However, some diseases and pests do attack iris and they must either be prevented or destroyed if we are to have a healthy garden we can take pride in. You should maintain a clean garden since many pests and diseases hide in garden debris and over-winter there. An iris garden should not be over-watered, overcrowded, or overfed if it is to be healthy. In warmer climates, overhead watering spreads diseases, overcrowding keeps the air from circulating and overfeeding makes large, but soft, rhizomes.
When spraying or dusting, there are a few basics to remember. Be careful of yourself, others and animals, as all sprays and dusts are poisonous to some extent. Read and follow the directions, both as to dilution and spraying intervals. Be sure to use the right product that is approved for use on irises to control the pest or disease that you are trying to control. If unsure, consult your nurseryman or County Agricultural Agent. Use sprays only if there is a need for them. Preventative spraying is fine, but it is more ecologically sensible to spray only when you find a pest or disease causing a problem. The diseases and pests discussed below are the most common ones affecting irises and the suggested treatments are generally the most common and easiest to use. Not all pests or diseases are found over the entire country, so we are fortunate.
-- Main.RPries - 2010-10-13