If you do use mothballs, remember that there are two kinds,
napthlene(sp?) and paradichlorobenzene. It's the
paradichlorobenzene ones you want. They also should be
flakes, and not "balls". I've also read elsewhere that the soil
you mound over the flakes has to be "disposed" of after you
remove it.
I found these web sites by searching on Google by search on
paradichlorobenzene (For first site) and then
paradichlorobenzene and fruit for the rest: