I posted this on the Ornamental Grasses forum, but got little help. Someone there suggested I post here.

I planted a Miscanthus Malepartus about 2 years ago, but it never did well. Other Miscanthus's are happy in these conditions.

The Malepartus began to flower this fall but the flowers haven't developed well - I looked closely and the stems were developing dark splotches.

I did some quick searching in the Ornamental Grasses forum and thought that it might be Miscanthus blight, so I went off to a reputable garden center to get some fungicide. I brought a sample of the infected grass with me.

The garden center personnel pulled the sample apart and found a white cottony substance and a beige insect inside. They said it was cottony scale and there was no treatment for ornamental grasses. They suggested I throw out the plant, or try cutting it way down and check it again in the spring. Maybe I'd be lucky and cut the insects off.

I went home and did a search for cottony scale, and a search for Miscanthus Mealybug.

This is what it looked like:

Miscanthus Mealybug

so I'm betting it's the mealybug, not cottony scale.

I'd like to keep the grass if possible, my questions are:

- Is cottony scale common on Miscanthus?

- If this is actually Miscanthus Mealybug, is it reasonable to cut the grass down to a few inches now and drench the soil and plant with imidacloprid in the spring?

The Malepartus is right next to a Miscanthus Little Kitten and several Panicum virgatums, none of which appear to be infected right now.

This clump of grasses is designed to be a wind barrier for a bird feeder, so I'd like to keep it reasonably intact through this winter. I'm in southeastern MA.

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RE cutting it down now rather than in the spring - I know the mealybug is dormant, but we get fierce winter winds here and I don't want the dormant bugs to get blown around into my other miscanthus's (miscanthuses?).

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I decided to cut the grass down a few days after I first posted, after a very windy day. I really don't want to spread the mealybugs to the other grasses.

I then dug out the Bayer's Rose and Flower spray (imidacloprid) I keep for the lily leaf beetles and I poured the stuff over the cut stems. In the spring I'll use the soil drench (it contains fertilizer so I don't want to use it now).

I've never cut miscanthus when it was still mostly green, and I was astonished to see that about half of the stems had a blood red core at the base. The rest were greenish-white. I even checked my fingers to make sure I wasn't bleeding.

Is this normal? or indicative of some other frightening condition?

Thanks,

Claire