Early spring pests and to-do list

By John Fulton

[April 25, 2013]  Early in the spring, there are many pests that become active. Many of these are timed by the saucer magnolia blooms, according to Orton's "Coincide" book. Spruce spider mites become active when magnolia blooms are in the pink stage. These mites are one of the major downfalls of spruce in our area. One of the early symptoms is a mottled appearance to the needles. Another is fine webbing attached to needles.

To determine if you have spruce spider mites, hold a piece of white paper under a branch and shake it. The mites will look like moving dust specks on the paper. Many times, there will be some fine webbing, like spider web, visible on the needles as well. Spruce spider mites can be controlled with sprays of acequinocyl, bifenthrin, cyfluthrin, insecticidal soap or summer oil spray. The soap or oil sprays will require a second application about a week later to give good control. These mites normally remain active until mid-May, but the cool conditions may extend their life cycle. These mites will again be active in the cool fall weather.

Spruce trees have a multitude of other problems they may encounter, so the spruce spider mites may only be a contributing factor. Some of the other problems are Rhizoshphaera needle cast, Stigmina needle blight, different root and butt rots, Cytospora canker, sudden needle drop, Weir's spruce cushion rust, spruce galls, and bagworms. For online descriptions of each of the spruce problems mentioned, see http://web.extension.illinois.edu/plantclinic/
downloads/Plant%20Clinic%20Report%20
Spruce.pdf.

Other spring pests are also indicated by the saucer magnolia. During the bloom stage, just finishing now, the ash plant bug, fall cankerworm, spring cankerworm, Fletcher scale, leaf crumpler, eastern tent caterpillar, juniper webworm and Zimmerman pine moth are susceptible to control. As we get to the petal fall stage, European pine sawfly, Gypsy moth, hawthorn mealybug, honeylocust pod gall and willow aphid become susceptible to control.

Reminders

• Mow the grass as it is needed. To do away with catching or raking grass, try to remove no more than one-third of the leaf blade. That first trip out with the mower usually shocks us how long some of the grass is.

• We have missed the first batch of crabgrass germination. Control is still possible with one of the organic arsenicals such as MSMA or DSMA sprayed on the recently germinated crabgrass, but it does stress the desirable grasses and may turn them some different shades of blue or green.

• Broadleaf control is just around the corner for many weeds. Look at early May for control.

• Grub control is largely unsuccessful in the spring because of large grub size and a short life cycle. Look to August and September for grub control.

• Moles are active, but controlling the grubs won't help much now. Look to a noose or scissor trap, or one of the soft baits with poison for control.

• The average date for the last killing frost is about May 5 for our area, and many gardening charts use May 10 for planting tender crops in our area. This would include squash, peppers, tomatoes, green beans and others.

• Prune flowering shrubs after they are done flowering. This will promote growth and hopefully maximize your flowers for next year.

• If you are interested in using the soil-applied treatment for Japanese beetle control on ornamental trees and shrubs, the earlier applications allow for better distribution in the plants. These treatments will not eliminate damage, but will reduce it by 50-75 percent since beetles must feed until they consume enough of the insecticide in the leaves.

[By JOHN FULTON, University of Illinois Extension]