This section is from the book "The Gardener's Monthly And Horticulturist V26", by Thomas Meehan. See also: Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long.
A correspondent finds her rhododendrons suffering from a stem borer which enters near the ground, as in the quince and other fruit trees, and from which the plants often break clean off, during a storm of wind, close to the ground.
We had not known, before, of the existence of such an enemy. Perhaps the yellowish looking plants often seen in a bed of rhododendrons may sometimes come from the attacks of these insects, though often attributed, and certainly with justice, to the attack of fungus. Either of these enemies would lead to yellow-looking plants.
The remedy is to examine the plants carefully every fall or spring, taking away the earth a few inches deep around the stem, and search for traces of the insects. If there, they will be readily detected by the sawdust they push out from their holes. Then thrust in a piece of stiff wire, which will destroy the grub which does the harm.