Friday, June 26, 2009

Jane: Horticultural Advice

I was on a radio call-in show today.

No, not Rush Limbaugh! It was "Talk at Twelve," the local NPR show. Friday is Horticulture day, and I called in with a question about my star magnolia. Eli and I noticed these odd white dusty blobs on the underside of some of its branches the other day.
And below them, sticky black goo coated some of the leaves.
The entomologist knew what it was immediately.

"You have something any entomologist would love!" he said. "Do you want it?" I asked.

These blobs are Magnolia Scale, an odd insect that is Iowa's only native scale. It looks like a fungus, but it's some kind of insect. These blobs are sucking the sap from my magnolia. The sticky goo is the remnants of the sap that they excrete, which turns black with a fungus.


Anyway, they suggested I begin by pruning the branches that have the most scale on them. Scale won't kill the tree immediately, but if they get it year after year, it will kill them.

I can also apply a systemic herbicide called imidacloprid that gets into the tree's sap and kills the scale. I may try that as the tree does seem to have a lot of scale on it, even after I trimmed the worst parts.

I blame it all on the hot and humid and rainy weather we've been having! One of my (non-fancy) hostas seems to have an aphid infestation as well. Ugh!

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