Research Report
Lemon Grass (Cymbopogon citratus Stapf) Methanol and Ethanol Extracts, a Repellant with Less Insecticidal Effect on Maize Weevils (Sitophilus zeamais Motschulsky) Infesting Maize (Zea mays) Grains
Author Correspondence author
Plant Gene and Trait, 2017, Vol. 8, No. 5 doi: 10.5376/pgt.2017.08.0005
Received: 03 Aug., 2017 Accepted: 23 Aug., 2017 Published: 27 Oct., 2017
Salami O.S., and Olufemi -Salami F. K., 2017, Lemon Grass (Cymbopogon citratus Stapf) methanol and ethanol extracts, a repellant with less insecticidal effect on maize weevils (Sitopilus zeamais Motschulsky) infesting maize (Zea mays) grains, Plant Gene and Trait, 8(5): 56-60 (doi: 10.5376/pgt.2017.08.0005)
The insecticidal efficacy and repellant activity of lemon grass (Cymbopogon citratus) extracts were investigated within laboratory conditions of 28±2°C and 72±5% temperature and relative humidity respectively, against maize weevil Sitophilus zeamais. The results showed that both methanol and ethanol extracts of C. citratus have no contact toxicity against adult S. zeamais. At the highest concentrations (25.00%) of the extracts used, none of the S. zeamais died after 7 days of post treatments. The percentage damages on the treated seeds of maize also revealed that the percentage damages done on the treated seeds decreases as the concentration of the extracts used increases. The highest and lowest percentage damages of 17.17% and 0.67% were observed in the untreated control grains and grains treated with 25.00% concentration of methanol extract. The same pattern was observed in the ethanol extract treated grains; only with slight increases in the percentage damages of the untreated control grains and grains treated with 25.00% concentration of ethanol extract. The repellant activity of the extracts showed that at 10% concentration and above, produced 100% repellant effect on S. zeamais in both methanol and ethanol extracts. C. citratus extracts is a good repellant with less contact toxicity on S. zeamais.