Evaluation of contamination of packages containing cereal-fruit bars by eggs of the pest Indian meal moth (Plodia interpunctella, Lepidoptera) due to perforations in their polypropylene foil packaging.

The quality and type of food packaging affect the level of food protection against pests. This work first evaluated the effect of package perforations on the infestation of cereal-fruit bars by the eggs of the Indian meal moth (Plodia interpunctella). We measured the differential oviposition of moths on the unpackaged bars, empty packages, bars in packages and bars in perforated packages in choice and no-choice experiments. Almost 100% of the laid eggs were laid directly on the bars when they were placed in the enclosure without packaging. A low proportion of the eggs (0.4-3%) were laid on either the empty or non-perforated polypropylene foil packages. Plodia interpunctella efficiently located and infested the bars with eggs when 5 mm package perforations were present in no-choice test. In choice test P. interpunctella preferred to oviposit on open bars than on the packaged or perforated bars. After deposition on the bars the egg hatchability ranged between 40 and 74%. For the food industry, the most significant practical conclusions of this study are that non-perforated packages provide protection against oviposition of P. interpunctella, but small perforations enable the moth to infest the resource with eggs.