Nursery - Black Vine Weevil Active in Container Perennials

Black vine weevil is active this fall and is feeding on herbaceous nursery plant roots. The following is a good article on the subject from the University of Maryland.

Black Vine Weevils

Adult females notch the edges of the foliage in June through September. The larvae will continue to feed on the roots of herbaceous perennials until late fall when they will migrate down to the bottom of container grown plants. Susceptible hosts include: Astilbe, heuchera, hosta, sedum, bergenia, aster, lily of the valley, foam flower, epimedium, fern, cranesbill geranium, heather, liriope, peony, phlox, and toad lily.

Black Vine Weevil damage to roots.

Black Vine Weevil

Chemical Control: Bifenthrin (Talstar) applied as a soil drench will control larvae.

Biological Control: Several species of entomopathogenic nematodes applied as a soil drench are effective including; Steinernema carpocapsae, S. glaseri, and Heterorhabditis bacteriospora (= heliothidis). In Europe, Heterorhabditis megidis has also been used successfully to control black vine weevil larvae. The nematodes will reproduce inside the black vine Black Vine Weevil Damage weevil larvae, and then migrate out into the soil to look for another host. For nematode survival, the soil must be kept moist and soil temperatures must be above 10° C (50° F). Steinernema kraussei has been used to control black vine weevil at temperatures between 43-50° F. This species may be a good choice for growers at this time in the fall.

Adapted from an article in the October 24, 2008 edition of the TPM/IPM Weekly Report for Arborists, Landscape Managers & Nursery Managers from the University of Maryland Cooperative Extension.