New Llano, Lo
|Why does my Iris's have rust colored spots. What is the cause? How do I cure it?
|Answer from NGA
April 15, 2010
|If the spots are actually spots and not long streaks, it's a fungal disease and a fungicide can help. But iris borers feeding on the rhizomes can also cause rusty areas on the leaves. A well-timed insecticide application can help reduce an iris borer infestation. Two options are acephate (Orthene) or spinosad (Bulls-Eye). It is important to time the application when eggs are just hatching. This is approximately when new growth is about four to six inches high. A repeat treatment 10-14 days after the first application may be necessary.
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