that's the bastage !!!
Head to your nearest farm/garden store,get a two or three jap beetle traps,they work great,i'm told spray will not work unles direct contact with insect,in my area they treat the soft soil in fall like your garden as they buroow down to lay eggs.
These traps use a sex hormone thet draws these little bastards by the 100's,once they fall into the trap they can't get out,just need to empty the trap daily,we're on week two and finally seeing the end game.
Interesting find maddog,I'm down to one trap this week,they have migrated elsewhere or died,like maddog I empty the traps in a bucket of soapy water.
With that said my neighbor has quite the trapline set,has a row of 6 traps along his rasberries and another 6 along the treeline out back,they seem to like birch and elm leaves.
So maybe thats the fix,buy traps for your neighbors,tell them the area in infested with these beetles,let them put the traps out~to keep your yard bettle free.