Effect of PVG treated polymer packaging on fecundity, Egg hatchability and egg to adult emergence of Tribolium castaneum Larvae development of Lasioderma serricorne
Abstract
Dry foods, both in raw and processed forms, face contamination and infestation by insects during storage and/or long transportation cycles. Provision Value Gard (PVG) has a unique, organic, and safe, approach to interrupt the growth cycle of insects in packaged foods thereby decreasing the loss of food, the need for harmful pesticides and the overall costs. This paper documents tests conducted to determine the efficacy of the PVG solution with respect to common insect pests associated with the loss of dry foods in India.
The egg hatchability and growth from egg to adult emergence of red flour beetle, Tribolium castaneum and cigarette beetle Lasioderma. serricorne, were evaluated in untreated and PVG treated packaging materials at an average ambient temperature of 32ºC and an average of 60 percent relative humidity (R.H). To test these entire hypotheses, 9 cm diameter packaging samples were placed in petri dish and 2 grams of a food source were added to the arenas. One group of arenas had 50 Tribolium eggs added. The second group of arenas had 30 Lasioderma larvae added. The hatchability of Tribolium was consistently lower in PVG treated packaging as compared to the untreated packaging. There was no development of larvae to pupa in any of the PVG treated arenas. Similar results were observed with the larva of Lasioderma.
None of the eggs emerged into adults in PVG treated packaging materials. Thus PVG solutions appear to fulfill the promise of effectively inhibiting the growth of T. castaneum and serricorne.
- Introduction
Stored product insects are a recurring and persistent problem in retail shops and storage godowns where they cause damage to food products. In India, the damage of stored grains by insect pests was estimated as 6.5 percent of the total storage amount (Raju, 1984). Infested food products result in infection and health issues, thus makes the consumers to loss their confidence. Both red flour beetle, T. castaneum, and the cigarette beetle, L. serricorne are pests of stored food products worldwide. They attack stored grain and processed foods including flour, cereals, pasta, biscuits, beans, and nuts, etc. Innovations in food packaging are being adopted by Indian packaging companies to make the packaging more resistant to infestation problems so as to increase the shelf life of food products and to reduce losses, while being safe for humans. These options can be prohibitively expensive.
Provision Value Gard provides protection to multiple forms of packaging materials, by arresting the growth and development of insects at the earlier stage. It affects larvae moulting and transformation from the larvae to pupal stage or from pupal to adult stage. The objective of this study was to determine the effect of untreated and PVG treated packaging materials on egg hatchability and growth from egg to adult emergence of T. castaneum and L. serricorne.
2.Materials and methods
2.1 Culturing of Insects
T. castaneum used in this study were obtained from laboratory cultures at the Indian Institute of Food Processing Technology, Thanjavur. Cultures of T. castaneum were reared under ambient temperature of 28 to 30°C and 60 percent R.H. with wheat flour as food source in 12cm glass jars fitted with filter paper lids and covered with cloths.
To obtain eggs, adults of T. castaneum with uniform ages were introduced into glass jar containing 100 gm of fresh un-infested wheat flour. The containers were incubated at 30°C and 60 percent RH. After 24 hours, the adults were removed from jars by sieving through BSS No.30(0.500mm) sieve. Adults were retained on the top sieve and wheat flour with eggs was collected at the bottom sieve. Eggs were collected from flour by sieving through BSS No. 60(0.250 mm) sieve. L. serricorne used in this study were also obtained from laboratory cultures at IIFPT. Cultures of Lasioderma were reared under ambient temperatures of 28 to 30°C and 60 percent. Wheat flour was provided as a food source in 12 cm glass jars, fitted with filter paper lids to prevent contamination.
To obtain larvae, adults of L. serricorne with uniform ages were introduced into glass jar containing 100 gm of fresh uninfested wheat flour. The containers were incubated at 30°C and 60 percent RH. After 24 hours, the adults were removed from jars by sieving through BSS No.30(0.500mm) sieve. Adults were retained on the top sieve and wheat flour with larval was collected at the bottom sieve. After 3 days, larvae were collected from flour by sieving through BSS No. 60 (0.250 mm) sieve and counted through stereo zoom microscope (LEICA S8AP0).
2.2 PVG treated materials
Seven types of PVG material supplied by Provision Value Gard were used in these experiments. The details of material supplied were given below,
- A) Single layer of Polyethylene film treated with 3% PVG 81086 was extruded by blownfilm extrusion process. PVG additive was added during the polymer loading of extrusion process. The polymer films were of 40 microns thick.
- B) Single layer of Polyethylene film treated with 2% of PVG 81086 was extruded by blown film extrusion process. PVG additive was added during the polymer loading of extrusion process. The polymer films were of 40 microns thick.
- C) 3 Ply poly layer of HDPE, LDPE and LLDPE film blended together by extrusion coating process. PVG 81086 was added in the middle layer at concentration of 2%. The polymer film was of 80 microns thick.
- D) Woven Poly film laminated with PVG 81086 at 3% concentration. Woven poly film made of polypropylene laminated with LDPE and LLDPE by extrusion coating. PVG 81086 was added to lamination during extrusion coating. Lamination layer was 20 micron thick.
- E) Non-woven Bags treated with PVG 81086 at 3% concentration. The non-woven bags are made of polypropylene by spun bond extrusion process. PVG 81086 was added at the time of loading at the rate of 3%. These materials were of 80 microns in thickness.
- F) Mono carton boxes treated with PVG 23207 Top Coat added during the printing process.The top coat of mono cartons was 5 microns thick.
Experiments
To determine the effect of packaging material on life stage of T. castaneum and L. serricorne, both untreated and PVG treated materials were cut to size and inserted into the 9cm diameter petri dishes. Approximately two grams of wheat flour was added to each dish.
(i) T. castaneum
Three days old 50 eggs of T. castaneum were added to each petri dish and incubated at 27 to 30ºC and 60 percent RH. The experiment was conducted in triplicate. The set up was kept undisturbed in the laboratory for a period of 45 days to observe full life cycle of red flour beetle, castaneum. Temperature and humidity were monitored throughout the experimental period with a data logger. Percentage of survivability was found using the following formula.
(ii) L. serricorne
Thirty larvae of L. serricorne were added to each petri dish and incubated at 27°C to 30ºC and 60 percent R.H. The experiment was also conducted in triplicate. The set up was kept undisturbed in the laboratory for a period of 60 days to observe full life cycle of L. serricorne. Temperature and humidity were monitored throughout the experimental period with a data logger.
- Results and Interpretation
3.1. Untreated control
(i) T. castaneum
The results showed that 86 percent of the eggs hatched into larvae in the untreated control. These larvae developed into pupa and then emerged into adults in a period of 45 days.
(ii) L. serricorne
It was observed that the larvae completed its life cycle and the newly emerged adults laid eggs which resulted in an average increase of 149% on 60th day.
- A) Single ply poly treated with 2% PVG material
(i) T. castaneum
The eggs released in 2% PVG treated single ply poly arenas showed that 67% of the eggs hatched into larvae. There was no further development to pupa and adults on 45th day. This can be attributed to the inhibition of growth by the 2% PVG treated single ply poly bags in the larval stage, whereas in the untreated packaging the majority of the larvae grown into pupa and adult stages.
(ii) L. serricorne
The effect of 2% PVG treated single ply poly packaging material showed that none of the released larvae developed into pupa. The result indicated that PVG treated single ply poly bags inhibited the growth of the larva.
- B) Single ply poly treated with 3% PVG material
(i) T. castaneum
The eggs released in 3% PVG treated single ply poly arenas showed that 73% of the eggs hatched into larvae. There was no further development of larva to pupa and adults on 45th day. This can be attributed to the inhibition of growth by the 3% PVG treated single ply poly bags in the larval stage, whereas in the untreated packaging the majority of the larvae grown into pupa and adult stages.
(ii) L. serricorne
The effect of 3% PVG treated single ply poly packaging material showed the none of the released larvae developed into pupa. The result indicated that 3% PVG treated single ply poly bags inhibited the growth of the larva.
- C) Three Ply poly treated with 2% PVG material
(i) T. castaneum
The results showed that 88% of the eggs hatched into larvae in 2% PVG treated three ply poly arenas. There was no further development of larva to pupa and adults, when observed on 45th day. This can be attributed to the inhibition of growth by the 2% PVG treated three ply poly bags in the larval stage, whereas in the untreated packaging the majority of the larvae grown into pupa and adult stages.
(ii) L. serricorne
The effect of 2% PVG treated three ply poly packaging material showed the none of the released larvae developed into pupa. The result indicated that 2% PVG treated three ply poly bags inhibited the growth of the larva.
- D) Woven laminates treated with PVG material:
(i) T. castaneum
The results showed that only 10% of the eggs hatched into larvae in PVG treated woven laminated arenas. There was no further development of larva to pupa and adults on 45th day. This can be attributed to the inhibition of growth by the PVG treated woven laminated bags in the larval stage, whereas in the untreated packaging material, the majority of the larvae grown into pupa and adult stages.
(ii) L. serricorne
The effect of PVG treated woven laminated packaging material showed only 2% larvae developed into pupa. The result indicated that PVG treated woven laminated bags inhibited the growth of the larva.
- E) Non-woven bags treated with PVG material
(i) T. castaneum
The results showed that none of the eggs hatched into larvae in PVG treated non-woven laminated arenas. This can be attributed to the effect of treatment on the eggs.
(ii) L. serricorne
The effect of PVG treated non-woven laminated packaging material showed the none of the released larvae developed into pupa. The result indicated that PVG treated non-woven laminated bags inhibited the growth of the larva.
- F) Mono cartons treated with PVG top coat:
(i) T. castaneum
The results showed that 67% of the eggs hatched into larvae in mono cartons treated with PVG top coat. There was no further development of larva to pupa and adults on 45th day. This can be attributed to the inhibition of growth by the mono cartons treated with PVG top coat in the larval stage.
(ii) L. serricorne
The effect of PVG treated mono cartons packaging material showed the none of the released larvae developed into pupa. The result indicated that mono cartons treated with PVG top coat bags inhibited the growth of the larva.
- Conclusion
The present study has demonstrated the effectiveness of Provision Value Gard treated packaging materials against red flour beetle, T. castaneum and cigarette beetle, L. serricorne. Exposure of egg stage of T. castaneum to PVG treated packaging materials showed efficacy in inhibiting the growth of larval stage and further development of insects. The packaging treatment with PVG could be used as a preventive method to help manage stored products insects in areas where bagged and packaged food products are stored. Thus PVG products will effectively help in the inhibiting the growth of T. castaneum and L. serricorne.
<em>Effect of PVG treated polymer packaging on fecundity, Egg hatchability and egg to adult emergence of Tribolium castaneum Larvae development of Lasioderma serricorne</em>
Effect of PVG treated polymer packaging on fecundity, Egg hatchability and egg to adult emergence of Tribolium castaneum Larvae development of Lasioderma serricorne
Project Leader: Dr. M. Loganathan
Assistant: Mr Akash, PA
Effect of PVG treated polymer packaging on fecundity, Egg hatchability and egg to adult emergence of Tribolium castaneum Larvae development of Lasioderma serricorne
Indian Institute of Food Processing Technology
(Ministry of Food Processing Industries)