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
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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.
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Broadleaf control
is just around the corner for many weeds. Look at early May for
control.
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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.
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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.
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The average last
killing frost date 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.
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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] |