Don't spray anything on a wilted plant. Foliage that is stressed for moisture is more vulnerable to spray damage.

Soft tip growth can wilt in the afternoon just because the sun came out after a cloudy spell.

If leaves are only wilted on one cane, the cane is probably broken or cankered at the base.

If the whole plant wilts suddenly and severely, voles may have chewed off the roots. Rock the plant to see if it is anchored.

Then there are a couple of systemic diseases that can cause wilting, but they are unusual.

If voles have gotten to it, you may still be able to save it. If there is a possibility of voles, worth spraying with castor oil to get rid of them.
kay

If voles have gotten to it, you may still be able to save it. If there is a possibility of voles, worth spraying with castor oil to get rid of them.
kay

If something's eaten the roots, it may help to take it up, cut it back, and soak it in water for a couple of days, in a shady spot. Then, pot it up.

If it is an own root plant, it can grow new roots. If it's budded, it might go own root. Worth a try, anyhow.

jeri