Post-harvest waste of spice crop used against storage pest -

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Post-harvest waste of spice crop used against storage pest

                 Post-harvest waste of local cardamom plants (Amomum cardamomum Wild.) such as stem and leaves have no economic value but potential as a bioinsecticide. It was known to contain insecticidally active ingredients. This study aimed to analyze the behavioral response of adult Sitophilus oryzae, L. under two shapes extract from post-harvest waste of local cardamom as the repellent control. The behavioral response was observed by the Preference Index (PI) value and Percentage of Repellency (PR). PR values were significantly under difference of doses and shape, while the optimally doses at 100%. PR value of extract was 57.6%, higher than the powder which was only 52.8%. It is found that rice weevil adult has the ability to respond behaviorally to post-harvest waste of local cardamom plants, but extract shape is more effective than powder. This study provides positive information about the potential that post-harvest waste of local cardamom as an economically-value bioinsecticide.

Powder and extract preparation

Material samples from post-harvest wastage of local cardamom (stem and leaves) in a ratio of 1:1 were washed, cut into pieces and dried in the shade. Dried samples were milled mechanically and stored in an airtight container. This powder was partially packed in a tea bag for powder treatment tests. Others were macerated in 96% ethanol with a ratio of 1:1 to obtain 100% extract, and then extract 100% was stored in a dark glass bottle. Some extracts were taken to be evaporated and analyzed its contents of the active compounds using the GC-MS method.

Rice Weevil Culture

            Male and female adult rice weevil were cultured in rice media at room temperature of 28 oC ± 1oC and humidity of 75% ± 5%, with a female-male ratio of 1:3. Adult rice weevil from the first generation (F1) of breeding, unsexing were used for the experiments.

Behavioral response of rice weevil to repellent effect

The behavioral response of rice weevil adults to odor stimuli (powder and extract of cardamom plant wastage) was measured by using the Y-shape olfactometertube. Olfactometer with 3 connected glass tubes (Y shapes, 10 cm long, 2 cm diameter). Each of tubes were connected with a glass bottle (3.5 cm long, 2 cm diameter), and another end of the tube was used to introduce insects. To confirm the repellent effect cardamom plant respectively. Liquid maceration 100% were assumed to be doses of 100% crude extract. To get a dose of 75%, 50% and 25%, liquid extract diluted using 70% alcohol. Powder treatment was also made in 4 levels of treatment, in this study, 100 mg of powder was assumed to be equivalent to 100% (100μL) of crude extract, because it was obtained from the maceration of the material in a ratio of 100 g of powder: 100 ml of 96% ethanol solvent (1:1). Each treatment was given as much as 100μL of extract dropped into Whatman filter paper (2cm in diameter). The filter paper was allowed to evaporate for 1 minute, then folded and placed inside the glass bottle, which was attached to each end of the olfactometer’s arm. Arm A was given filter paper according to treatment; arm B was only given filter paper without crude extract as a control.

                 Y-olfactometer was placed horizontally on a white paper. A total of 25 unsexed rice weevil were put in the tube. A total of 25 unsexed rice weevil (test insects) were introduced into the olfactometer. If rice weevil did not like the odor stimuli of powder or crude extract on arm A, they were assumed to be reversing towards the arm without treatment (B). After 60 minutes no displacement occurred, the number of rice weevil found in each olfactometer’s arm was recorded. The powder and crude extract of cardamom plant were tested separately in four doses, and each dose was replicated 5 times. Behavioral responses of the repetition of rice weevil due to the effect of treatment were stated as the Preference Index (PI) and Percentage of Repellence (PR). Negative values of PI indicated that post-harvest waste of local cardamom has a repelling effect on rice weevil. PR value was used to find out how strong the repellent effect of the material was on test insects.

Results

                 The stem and leaves of cardamom plants have a similar aroma to the part of the seed. This is a marker there are the same essential oil compounds in both organs. GC-MS analysis showed that the phytochemical compounds in the cardamom stem and leaf extract were dominated by a high percentage of fatty acid, namely palmitic acid, 13-trans-13-octadecanoic acid and Oleic acid. It also detected essential oils such as p-Cymol; 1.8 Cineole; Sabinol; Isothymol; ascaridole and Piperitone, as well as saponin and flavonoid. Based on these results, the waste of cardamom plants has the potential as an economical source of bioinsecticides.

Production of repellents derived from plants may be easier and cheap than the synthesis of some more complex attractive semio chemicals. Therefore, developing bio insecticide from natural materials with no economic value today is a strategic alternative. Inexpensive materials, abundant availability and their use do not compete with human needs, are some considerations to produce economically profitable products. Repellents from plant origins are considered safe in pest control operations as they minimize pesticide residues; ensure the safety of the people, food, environment, and wildlife.

Percentage of repellence

                 The response of rice weevil to the repellent effect of powder and extract cardamom plant can be seen from the percentage of repellency (PR). The highest PR value is found in 100% doses, both in powder and crude extracts. In high concentration, the natural oil from cardamom acts as a potential grain protectant by thuggery various life stages of the insects attacking wheat, such as T.castaneum and S. zeamais, via contact and fumigant action. In this study, the post-harvest wastage from cardamom stems and leaves is known to contain oil essential as like in seeds, but the concentration is low. Therefore, the bioassay- test on rice weevil causes repellent effects only doesn’t have an impact on mortality.

Based on the established criteria, the use of powder up to 100 mg gives a medium category repellent effect (PR 52.8%). But in the extract treatment, the repellent effect was seen at 75% and 100% extract dosages with a range of 53.6 – 57.6%. It indicates that cardamom waste in extract form gives a better repellent effect than cardamom waste in powder. It means rice weevil had given a rejection response to cardamom extract at a dose of 75%, while the rejection response to new powder is detected by rice weevil at a dose of 100 mg. It happened because the aromatic compounds in the extract evaporated faster and spread more widely than aromatic compounds bounded in the powder.  The volume of the Y-olfactometer tube is approximately [3.14 x (2.3) 2] x 10 cm3 = 180 cm3 (= 180,000 μL). Based on the results of this study, is to provide positive information about the potential that post-harvest wastage of local cardamom as an economically-value bioinsecticide.

Conclusion

                 This study provides positive information about the potential that post-harvest waste of local cardamom as an economically-value bioinsecticide. The findings of this study also inform farmers that bioinsecticide can be easily prepared using the simple and available materials.

Reference:

Widiyaningrum, P., Candrawati, D., Indriyanti, D.R. and Priyono, B., 2019, October. Behavioral response of Sitophilus oryzae L. to repellent effect frompost-harvest waste of local cardamom. In Journal of Physics: Conference Series (Vol. 1321, No. 3, p. 032028). IOP Publishing.