What's eating your snowball bush? ... or who?
Like many Islanders... you might have a snowball bush in your backyard. Have you noticed lots of holes in its leaves?
You likely have an infestation of the viburnum leaf beetle (VLB)!
This small beetle is native to Europe and Asia and was first found in North America in 1947... in Ontario!
The VLB feeds exclusively on Viburnum spp. Some species are more susceptible than others so when planting viburnums its a good idea to do a bit of research.
The adult is a small, brownish beetle that lays it eggs on Viburnum spp. in the twig tips. If you look at the twig tips you will see "egg caps". If you peal back the "cap", which BTW is made up of excrement, chewed bark and mucous secretions... I know TMI... you will find masses of small, yellowish eggs. The VLB overwinters in the egg stage and in the spring hatches as the leaf buds begin to open. The larvae are small and yellowish with black markings. They feed on leaves and flowers and can defoliate an entire shrub. The mature larvae drop to the ground and enter the soil to pupate around mid-June. The beetle emerges about 10 days later and also feeds on the leaves of the viburnum shrubs.
The best way to control VLB is to prune off all the twig tips where the eggs have been laid. A good time to do this is in the spring before the leaves have emerged. The egg caps are readily visible at this time and the eggs won't have hatched yet.
There's some great information on the following websites. There is even a Citizen Science project you can take part in!
- Beth Hoar, Chair, PEIISC