There are many vegetables, legumes etc which according to poskim need to be checked for bugs due to insect infestation. Can anyone tell me if this is also true for popcorn kernels?
According to the current (updated February 7, 2014) version of the Star-K's "Insect Checking Quick Reference Guide for Mashgichim", corn doesn't need to be checked for infestation. It does say that the corn should be stored sealed and in a cool, dry area to prevent infestation. [And, of course, if the corn is obviously infested, don't eat it.] It doesn't differentiate between popcorn kernels and any other type or form of corn.
According to Rabbi Moshe Vaye popcorn kernels should be checked.
A. Strain, over a white surface, in a strainer with large holes and check whether any small insects are found among the debris that fell through.
B. Spread out a handful of kernels at a time on the palm of your hand, and look for insects among the kernels or round holes in the kernels. Turn over onto the other hand and check the other side (Illustration 391). A black dot at the tip of the kernel is not an indication of infestation (Illustration 392). If definite infestation is found, it is preferable not to use the kernels, since there may be internal infestation that is undetectable from the outside.