Alas, Rose Chafer beetle season is upon us here at the Gardens of Box and Bay. A three to six week onslaught of mating, flying, wriggling masses of bland beetles with a voracious appetite and no known predators.
I see you up there you bad word!
We are lucky in that we really only have one major (knock on wood) garden plague and this is it. Thankfully they only have one hatch a year. Thankfully they don’t stick around forever. And thankfully they aren’t harmful to us.
On the other hand… they are toxic to anything that would consider eating them (my very first thought upon discovering them 3 years ago was chickens/ducks/guinea fowl). Nothing kills them reliably that won’t also kill me and everything else. They eat just about anything (fruit, flowers, foliage- totally indiscriminate). They have orgies on your plants. And the only really reliable way to kill them to attempt to control numbers is manually.
Soap. Water. Bucket. Hands.
I’ve done my fair share of research each year they arrive. It is always in some feeble hope of finding out someone, somewhere came up with a real-deal organic solution to annihilating these guys in the past 12 months. They’ve not done it yet.
The nearest ‘solutions’ I have found are really Integrated Pest Management (IPM) techniques geared less towards killing the beetles and more towards making your space less inviting.
- Beneficial Nematode application via soil soak. This is costly and the nematodes may not overwinter in our climate (no one is 100% sure of their hardiness apparently). It is also the only ‘solution’ that does have the ultimate goal of killing them, just at the larval stage. I certainly wouldn’t dream of trying to soil soak 3.5 acres though so I’m not sure if doing selected areas near valuable targets is even worth it.
- Seeding the lawn with clovers to make the soil harder to reach and less appealing to the egg-laying females. Not as costly, but very labor intensive. Our ‘lawn’ is crap though, so this could end up being a win on multiple fronts if it works. This is likely a late summer-early fall project in the making.
- Pheromone traps. I’m still not sold on these. The fear (or at least the fear I was taught in Master Gardener training) is that these traps usually only serve to bring more bugs into your area and don’t kill as many as they attract.
- The one I’m least fond of is just suggesting you get rid of the plants they seem to visit most. I agree with this in principle, but with a non-specific pest, I worry that removing the birch tree will only mean they move on to the peonies and raspberries they are currently ignoring (praise be). Perhaps the birch and Viburnums are best used as a ‘trap crop‘ since we know they love them and it seems to keep them out of the rest of the garden.
The problem, of course, is that our soil is the absolute perfect habitat for these guys so any improvements we make will likely only be incremental. All out eradication is nothing we could even hope to achieve. Sad trombone.
Since we know from experience they will go after our precious apples (and eventually the plums too), we bought reuseable fruit bags last year on Amazon, (Clemson University has super affordable ones through their orchard program as well). I spent last evening up on a ladder trying to tie these things on without crushing the branches or damaging the fruit. Its a pretty fiddly task, but at least the fruit should be protected until after the onslaught has ended!
Any foliar damage to shrubs and perennials generally recovers on its own a few weeks after the infestation ends and now that most of our plants are well established, my concerns for them are much lower. However, the skeletonized leaves aren’t a good look and make everything look wilty and unhappy.
They’ve somehow not made their way to our peonies yet. I’m hoping this is because the ground is so well mulched that the breeding conditions aren’t appealing and there is easier ‘prey’ elsewhere- much nearer to good egg-laying conditions. But I don’t dare plant a rose in our garden proper for fear it would be tantamount to a bad Black Friday frenzy.
Alas, the buckets of soapy water will forever be fixtures in the early summer gardens here.
What pests are your yearly battles and how do you go about managing it?