Submitted to: Insects
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/5/2018
Publication Date: 4/17/2018
Citation: Scheff, D.S., Sehgal, B., Subramanyam, B. 2018. Evaluating penetration ability of Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae) larvae into multilayer polypropylene packages. Insects. 9(2): 1-15. https://doi.org/10.3390/insects9020042. Interpretive Summary: The Indian meal moth, is cosmopolitan stored product insect found throughout the world. The Indian meal moth larvae is capable of chewing through packaging materials and infesting the product inside, but limited information is available on penetration of multi-layer packaging and there is a lack of a standard methodology to test packaging integrity. We found that small, medium, and large larvae were all able to chew through the three different packaging materials tested and infest the product. However, the larger larvae were able to chew through more of the different types of packages tested and caused more damage to the product. The thickest package was most resilient to penetration by the Indian meal moth larvae. In conclusion, the methodology presented in this study provides a standard to use when testing future packaging products against the Indian meal moth and that given the variation in penetration of different packaging materials there is potential for improving packaging designs to increase protect of products.
Technical Abstract: Larvae of the Indian meal moth, Plodia interpunctella (Hübner), can invade or penetrate packaging materials and infest food products. Energy bars with three polypropylene packaging types were challenged with eggs (first instars), third, and fifth instars of P. interpunctella to determine package resistance at 28°C and 65% r.h. The packing types were also challenged with two male and two female pupae of P. interpunctella under similar conditions, to determine which package provided the greatest protection against larval penetration. Samples infested with eggs, third instars, and pupae were evaluated after 21 days and 42 days to count the number of larvae, pupae, and adults found inside the packages. Packages challenged with fifth instars were observed after 21 days to count number of larvae, pupae, and adults inside each package. The number and diameter of holes were determined in each package, followed by the amount of damage sustained to the energy bar. Third and fifth instars showed a higher tendency to penetrate all packaging types. First instars showed a reduction in package pentration abiltiy compared to third and fifth instars. The increase in exposure time resulted in an increase in damage sustained to the energy bars. Among packaging types, the thickest package (Test A) was most resilient to penetration by all larval stages. In conclusion, energy bar manufactures need to invest more in improving packaging designs, thicker gauge films or odor barrier technology, to prevent penetration and infestation by P. interpunctella larvae.