Jenny wrote:

Back several months ago I posted about my miserable rhododendrons. Just
about every leaf had been eaten by a bug and I was contemplating pulling
them out.

The diagnosis was root weevils.

If they are black vine weevils or strawberry root weevils, they live in
the ground and climb up the plant each day to dine. Feeding is done at
night. Specimens may be collected at night for identification. The major
damage is caused by weevil larvae which girdle the roots and kill the
plant. Larvacidal drenches may be used to kill them but are of limited
effectiveness. A more effective approach is to use nematodes. They are
very effective against weevils when applied in the fall to control the
larvae. While this approach is promising, it has limitations in that the
beneficial nematodes are very sensitive to temperature and moisture
extremes and will not live over winter. If applied to soil that is too
cold, too wet, too dry or too hot, they will die and provide no control.
Best control is achieved by using both chemical and nematode methods
with proper timing. Foliar sprays are very effective at controlling
adult weevils when leaf notching starts. Foliar sprays of Orthene should
be sprayed at about three week intervals from about May to October,
depending on the weather, until no adults emerge. Since weevils feed at
night, you can hand pick adult weevils at night using a flashlight.
Since weevils spend the daytime in the soil and come out at night to
feed, you can paint the trunk with Tanglefoot to stop them, but make
sure no branches are touching the ground.
--
Pardon my spam deterrent; send email to
Visit my Rhododendron and Azalea web pages at:
http://home.earthlink.net/~rhodyman/rhody.html
Also visit the Rhododendron and Azalea Bookstore at:
http://home.earthlink.net/~rhodyman/rhodybooks.html
Cheers, Steve Henning in Reading, PA USA Zone 6