Scouting Watch

September 26, 2007

Magnolia scale is a pest of yellow poplar and other magnolias. It is more common in northern Illinois than in other parts of the state.

Magnolia scale and crawlers.

Crawlers are present from now until spring and susceptible to insecticide applications at this time. As winter approaches, many will move into protected locations—such as into bark crevices, making them less susceptible to control. Acephate (Orthene), insecticidal soap, and summer oil are effective at this time, as well as in early spring when the buds are opening.

Cooley spruce gall adelgid and Eastern spruce gall adelgid are exposed now and in early spring. They can be controlled at these times with carbaryl (Sevin), imidacloprid (Merit), insecticidal soap, and summer oil.

Cooley spruce galls.

Spruce spider mite becomes active and controllable in the fall after being in the egg stage during most of the summer. Acequinocyl (Shuttle), bifenthrin (Astro, Talstar), insecticidal soap, spiromesifen (Forbid), and summer oil are effective now, as well as in early spring. Scout for active mites before treating by holding a white sheet of paper under a suspected branch and striking the branch sharply to dislodge the mites onto the paper, where they can be easily seen. Spider mites streak green when smashed. Beneficial predatory mites streak red. If predatory mites are common on a tree, spraying for spider mites will probably be unnecessary.