About Black Vine Weevils
Black vine weevil host plants include over 100 different species, but they favor the following above all else:
Yew Hemlock Rhododendrons Azalea Mountain laurel Euonymus Japanese holly Grapes Liquidambar
These 1/2 inch (1 cm.) long beetles look much like the strawberry root weevil but are twice their size; they may be impossible to distinguish from other members of their family with the naked eye. However, if you’ve got damaged yews nearby, the chances are good that you’re dealing with black vine weevils. The adult form is fairly easy to spot and the damage is conspicuous, but the real trouble starts with their larvae. Since they burrow in the soil and feed on roots underground, getting rid of black vine weevils can be difficult. Larval feeding damage tends to be worst in the spring, when soil moisture drives the grub-like pests closer to the surface where they’ll happily girdle plants and chew bark.
Black Vine Weevil Control
If you catch black vine weevil adults feeding in your garden, they’re not all that difficult to defeat while their numbers are still low. It generally takes 21 to 28 days of feeding before they’re ready to lay eggs, so your first goal is to kill the adults before this happens. Hand-picking is one of the safest, though tedious, ways of eliminating large numbers of black vine weevils. Look for them toward dusk with a flashlight and drop all your hapless victims into a bucket of soapy water. When you know you’ve not caught all the weevils by hand-picking or your plant continues to suffer despite your efforts, it might be time to look into what kills black vine weevils besides human hands. The answer to that question is nematodes! Heterorhabditis spp. are recommended for black vine weevils because of their relative mobility and willingness to search deeper in the soil for prey. Follow the package directions when drenching with nematodes. One dose isn’t usually enough to get good results, so make sure you retreat a week or two later to help the nematode colony better establish itself.
