when I find this happening for mine I find I have borer in them and this year the borer is terrable...You should be able to see white droppings down along the leaaves where the borer droppings have came out the hole that the borer got in...Don't know how to cure the borer.Have tried for years and still have them...
Bluepoppy, try a product with Imidacloprid, which has to be applied early in the growing season to get the borers. I was plagued by iris borers last year, and I used the product earlier this spring and no borers so far. Now I just have to stay on top of the rabbits.
I would guess that it is Bayer Long season Grub Control with Merit, which is what I rely on for iris borers. Evidently there are a lot of borers, like corn borers, etc. For irises you have to put it on very early in the season for it to work - don't know about lilies, but I did have this problem with mine once and didn't know what to do.
Bayer season-long with Imidacloprid has gotten a bad rap as being the cause of bee colony collapse ~ which has been proven that it is not. I've used it for years and my garden has always been loaded with bees, from honey bees to big bumbles.
If I didn't use it on my shrubs I wouldn't have any. In fact, I delayed on my siberian pea hedge and it is all twigs and no leaves now. Hopefully it will return next year, but the aphids destroyed it. And leaf curlers are awful here and the bayer keeps them down to not much bother.
Loveforests, I've not had any problems with killing off bees or other insects either, the birds, bees wasps etc are very active in my garden this year as in any other year that I didn't use the Bonide. What I do have this year are much happier irises and NO borers yippeee!!!! Everyone is entitled to their own opinion, and shouldn't let others feel bad about posting something that works for them ;-). Annette
I use Bayer 12 month Tree and Shrub for both Iris ( first year I tried it ) and Lilies.
When lilies emerge so you can just see the red tips and when iris leaves are 2 inches I drench the soil around them.This is my first year for Bayer product. It has worked on lilies this year.Imidicloprid is the main ing.in all Bayer products.
In the past 2 years I used Sevin. I have very little beetle activity, practically none,earwigs are another matter.
Early spring drench is necessary to kill the beetle larve. This pest is wide spread in NewEngland and spotty other eastcoast states.
I have a business and have to use something, so I use the Bayer, like Jo does. If you could see all the different bees here, snakes, butterflies, frogs, and whatever, you would certainly never know I used any chemicals at all. Right now my hydrangea paniculatas are just covered with bees.
Of course we all need to use chemicals responsibly, but respect what others do, and do what you need to do.