Someone asked about Milky Spore works. I think it is supposed
to slowly spread out in the soil over 3 years [lasting up to 10 years]
and kill the Jbeetle grubs.
It is expensive [$30], but we have such a Jbeetle problem that I
thought we should try it. Our neighbor [with over 40 roses] has done
it to her property also. In a neighborhood you others to do it too.
Last year I discontinued the Jbeetle traps [I used those for about 5
years] and tried Neem. I have a cherry tree that Jbeetles love [as
well as my Kerria bush & the roses] & I sprayed with Neem daily.
I don't think it did enough. Hopefully the Milky Spore will work.
I still expect Jbeetles this year -- maybe less of them though. But
the warm winter in PA won't be helpful, I'm afraid. I'm just going to
dunk the things into soapy water -- after all, I cleaned aphids off
the roses 3 times a day at their height!
Good luck to all in the fight!