What bug eats viburnum leaves?

Help! Something’s Eating My Viburnum! A Guide to Identifying the Culprits

Viburnums. Aren’t they just gorgeous? Those lush leaves, the beautiful blooms, and let’s not forget the berries that the birds adore. They’re a landscape staple for good reason. But, like anything worthwhile, they can have their problems – specifically, pests that turn those lovely leaves into something resembling Swiss cheese. Figuring out who is doing the munching is the first step in saving your shrub.

The Usual Suspect: Viburnum Leaf Beetle (aka, the VLB)

If your viburnum looks like it’s been through a hailstorm (but without the actual hail), chances are you’ve got the viburnum leaf beetle, or VLB, on your hands. Pyrrhalta viburni sounds pretty intimidating, right? Well, this little bugger is originally from Europe and Asia, and it’s made itself quite at home here in North America. It first popped up in Canada way back in 1947, then made its way to New York State in ’96, and has been spreading ever since. In fact, the Royal Horticultural Society in the UK even called it their “number one pest species” back in 2010! That’s not a title you want.

The real trouble comes from both the larvae and the adult beetles, but honestly, those larvae? They’re the ones doing the bulk of the damage.

Spotting VLB Damage: A Detective’s Guide

• Larval Lunacy: Picture this: It’s springtime, maybe late April through June, and you notice the leaves looking… skeletal. The larvae are basically eating everything except the veins, leaving this lacy, see-through effect. I’ve seen it so bad that it looks like a delicate doily rather than a healthy leaf. They get to work even before the leaves fully unfurl, the little monsters.
• Adult Antics: Fast forward to late June and early July. The adults emerge, and they’re not exactly neat eaters. They chew these oblong, kind of irregular holes in the leaves. It’s like they’re using the leaves as a practice target.
• Total Defoliation Drama: Here’s the scary part: If you don’t get this under control, these pests can completely strip your viburnum bare. I’m talking naked branches. This weakens the plant over time, and after a couple of years of this heavy feeding, your viburnum might just give up the ghost. It’s heartbreaking to watch.
• Egg-Laying Evidence: Keep an eye out for this in late summer and fall. The female beetles lay their eggs right in the twigs. They chew little holes, deposit the eggs, and then cover them up with what looks like chewed-up wood. These twigs become brittle and break easily. It’s like they’re setting little booby traps for your plant.

Viburnum Pickiness: Who’s on the Menu?

Now, here’s a bit of good news: Not all viburnums taste the same to these beetles. Some are like a five-star restaurant, while others are more like… well, you get the idea. The VLB has its favorites:

• Arrowwood viburnum (Viburnum dentatum) – Apparently, this is prime rib.
• European cranberrybush viburnum (Viburnum opulus) – Another top choice.
• American cranberrybush viburnum (Viburnum opulus var. americanum) – Seems like cranberrybush viburnums are particularly tasty.
• Possumhaw viburnum (Viburnum nudum) – Also on the preferred list.

On the other hand, if you’ve got Viburnum carlesii or Viburnum plicatum, you’re in slightly better shape. These aren’t usually the VLB’s first choice.

Beyond the VLB: Other Leaf-Munching Marauders

Okay, so the VLB is the main offender, but it’s not the only one. Other insects might be taking a bite out of your viburnum, too:

• Sawflies: These guys look like caterpillars, and they eat like them, too. Some even spin webs on the leaves, which is just rude.
• Root Weevils: The adults leave these jagged, notched edges on the leaves. The real problem, though, is their larvae, which chow down on the roots. That can do some serious damage.
• Aphids: These tiny sap-suckers cause all sorts of problems, like twisting and curling leaves. Snowball aphids are especially fond of European cranberrybush and snowball viburnums.
• Flower Thrips: These slender insects will feed on leaves and flowers, causing purplish-red spots on the undersides of leaves and causing foliage to curl or drop prematurely .

VLB or Not VLB? That Is the Question.

So, how do you know if it’s really the viburnum leaf beetle? Look for that tell-tale skeletonization from the larvae and those oblong holes from the adults. And, of course, try to actually see the critters themselves.

Fighting Back: Taking Control of the Situation

• Regular Check-Ups: Get up close and personal with your viburnums. Keep an eye out for any signs of trouble. Early detection is key.
• Hand-to-Hand Combat: If you see larvae, pick them off and toss them into a bucket of soapy water. It’s a bit gross, but effective.
• Pruning Power: Get those pruners out! Cut off any infested twigs or branches, especially the ones with eggs. Destroy them – don’t just leave them on the ground.
• Chemical Warfare (Use with Caution): If things get really bad, you might need to resort to insecticides. But be careful! Use them as a last resort and always follow the instructions. Systemic insecticides can be effective, too.
• Smart Planting: When you’re choosing viburnums, think about planting those less-susceptible varieties. It’s like choosing the right neighborhood to avoid trouble.

By playing detective, identifying the culprit, and taking action, you can keep your viburnums healthy and beautiful. Happy gardening!