Question
QUESTION: Hi Jack,

I live in Hawaii on Oahu.  Today, I was transplanting my rose bush from its container when I noticed a grub worm in the soil.  I didn't know what kind of worm it was at first so I tossed it aside.  However, when I was sifting through the soil, I noticed there were 4 or 5 more of the same worms and I only figured out their identities when I checked online.  How can I control these pests?  I'd like to not use any pesticides so are there alternatives I can use?

ANSWER: Sean,

Can you post a picture? There are lots of different insects that people call "grubs". If these are "white grubs" (see http://www.livingwithbugs.com/white_grub.html) they are larvae of certain beetles but there are also moth larvae that some people call "grubs". The control options would be different for these two pests.

Jack DeAngelis




---------- FOLLOW-UP ----------

QUESTION: Hi Jack,

Yep, those white grubs are the ones.

Answer
I'm not positive about the Hawaiian fauna but rose chafer and/or Japanese beetle are two possibilities (see http://www.livingwithbugs.com/japanese_beetle.html). The adult beetles emerge in early summer and these can be hand-picked or treated with spinosad (see http://www.livingwithbugs.com/spinosad.html). Larvae in the soil are more difficult but nematodes or milky spore disease can be effective - see the page cited above about Japanese beetles. You might also google "white grubs hawaii".

Jack DeAngelis