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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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 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.
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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]
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