Welcome Paul,
How wet do you keep your plants? I wouldn't think grubs could
stand it if the plants were being kept at their 'normal' water levels.
The thing about your S.oreophila seems to also be caused by not enough
water. When that plant gets alittle to dry anytime after the first
growth, it will stop growing pitchers. This is an adaptation for
surviving through the dry summers. I can recall that others on the
list reported that if they allowed their S.oreophila to dry even
for a day or two, within a week all the pitchers would abort and none
would grow until next spring.
Dave Evans