Iris borer
Iris borer (Macronoctua onusta) is a pinkish caterpillar with rows of black spots on their sides. When full grown, it is about 2 inches long. The larvae emerge from the ground in April or early May when iris leaves are about 4-6 inches tall. They enter the leaves through tiny pinholes and burrow their way down to the rhizome. By midsummer they eat their way through the rhizome leaving only the outside shell and then return to the soil to pupate. In August-October, iris borer emerges as a night-flying moth with brown front wings and yellow-brown hind wings and a wing span of 2 inches. The moths will then lay creamy white eggs which later turn lavender on foliage or debris which will winterover and start a new lifecycle the following spring.
Early signs of iris borer are disfigured foliage with irregular tunnels in the lower section of the leaf and chewed leaf edges that appear in early spring. Leaves may also have water soaked streaks.
Bacterial soft rot
One of the major problems that iris borer introduces to the leaves and rhizomes is bacterial soft rot (Pecotobacterium carotovorum). Rhizomes become soft, mushy and have an offensive odor. The leaf tips are withered and leaves have long brown streaks or appear water soaked. Bacterial rot can also be introduced through careless cultivation. Crowded, shaded growing conditions can make the plant susceptible to infection. More info on iris..
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My bearded iris seem to be dying all of a sudden, the leaves are going brown, what can I do, I have been growing them for years and moved them in to the rose beds some time ago they grew wonderfully until last week.
Treating iris borer
Concerning my iris tubers with pinholes, how do I treat them? Someone told me about using a mild bleach solution but I don’t know how much or how long.
Thanks for all the info regarding Iris. Relative to the borer – please advise what do you do to the dirt in your beds to get rid of the borer? Need to know ASAP. Thanks
I WAS TOLD TO DIG UP AND DIP RHIZOMES OF THE IRISES IN 1 PART OF BLEACH TO 3 PARTS WATER AFTER CUTTING OFF ANY ROT WITH A KNIFE AND TO CUT BACK YOUR IRIS LEAVES IN THE FALL TO 3 TO FOUR INCHES TO RID OF EGGS LAID ON TIPS.BEST OF LUCK…Lorrie
The best way to get rid of bacterial soft rot, which is caused by a bacteria not the iris borer, is to scrape the rot from the rhizome without removing it from the ground and then pour Dial Aniti-bacterial Hand soap directly on the rhizome and the surrounding soil. I grow 300 varieties of irises and used to use the chlorox, but the soap works much better
Is this the kind you use straight from the bottle that is alchohol based or the regular liquid handsoap. And how much? Thanks Liz
Freeze damage
I have a few iris plants with leaves that have accordian like folds in them and some of the buds are deformed. Any answers Thx