Chemical control for Magnolia Scale?

A neighbor has been trying for the past several summers to either control or kill the Magnolia scale on his Magnolia tree.
His one and only method has been to apply some sort of oil spray via a hand-pumped sprayer. The tree is about 15 to 20 feet tall and naturally it's awkward and time consuming to apply the oil this way. The oil really doesn't seem to be having any effect. By late summer, many leafs have ugly black stains on them.
I read that the following chemical products are applicable in the control of Magnolia Scale:
ACEPHATE (Orthene), ABAMECTIN (Avid), CARBARYL (Sevin/Sevimol), DIMETHOATE (Cygon), MALATHION (Malathion), CHLORPYRIFOS (Dursban)
I believe that Cygon and Dursban are no longer available to the average consumer through stores like Home Depot, etc. I've only seen Dursban available as a granular for turf grass application anyways.
So my question is, which type of chemical control is available for Magnolia Scale that (1) can be purchased by an average home-owner and (2) can be applied via hose-end sprayer.
Can liquid malathion be applied via a hose-end sprayer in this situation? And if so, when is the best time of year to apply?
???
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It would be a waste of time and money to spray now since the scale are pretty dormant right now like the tree. I assume you're talking about a Japanese magnolia with the pink flowers that is deciduous? Spray early before the flowers open with oil or oil/Malathion (Diazinon, Dursban if you have them). After the flowers drop and as the foliage opens, spray with Orthene which has a contact and systemic affect. Treat the area around the tree for ants. It's unlikely that the scale gets there by itself. Ants are notorious for "farming" aphids and scale for the sweet secretions they make. Magnolias are not the only target. I've had ants spread aphids on hibiscus and scale on citrus. You can add Enstar to the Orthene for a major punch. Enstar is an insect hormone that prevents juveniles from becoming adults and they quickly die. It's expensive but works. Of course, it's all in vain if you allow the ants back. Good luck. Gary

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