katesflowers said:Some of my mature snapdragon plants are showing stages of wilt. If trimmed of the dead branches, the plant still eventually dies. Upon examining the roots, they seem fine, not suffering from strangulation. The plant leaves are not spotted, just wilted and died. Yet, adjoining plants & snaps in the grouping are fine. All have received regular watering.
Hi Kathy,
I am a zinnia hobbyist, so will respond according to my experience with zinnias. If these were zinnias, the culprit would be a stalk borer. It is the larva of a moth. It enters the stalk by eating a more-or-less circular hole in the side and proceeds to eat the insides of the stalk.
Some plants can withstand the damage without dying -- for example Giant Ragweed and some large thick stemmed sunflowers. Stalk borer attacks usually kill my zinnias, and your Snaps may also succumb.
If you still have the Snap in that top photo, try cutting the stalk in sections looking for signs of a borer. If you see signs of borer damage but no worm, it may have exited and be attacking another Snap stem. Sometimes you will find the stalk borer still in the affected stalk. One borer can kill several plants before it pupates. Catch-and-release is not a good idea with Stalk Borer larvae.
ZM
