Acanthoscelides obtectus (Coleoptera: Chrisomelidae: Bruchidae) is an insect pest which attacks the common bean (Phaseolus vulgaris, L.). It has been suggested that plant products, e.g. essential oils, may be a suitable alternative for controlling insect pests1, including A. obtectus2. The objective of this study was to determine the capacity of essential oils of Lippia spp. to control A. obtectus adults under laboratory conditions. One millilitre of solution (6 μL of Lippia orinanoides and Lippia alba diluted in 994 μL of ethanol) was sprayed (Potter tower) directly on Petri dishes (90 mm in diameter) covered with sterile filter paper. One hour after, twenty A. obtectus adults were placed in these Petri dishes. Four replicates were used for each Lippia spp. Daily monitoring of insect mortality was performed for 15 days.
Results (Figure 1) show L. orinagoides accumulated an insect mortality of 54%, significantly different from L. alba, which achieved a mortality of 43%. Both Lippia spp. treatments were significantly different from control treatment, with an accumulated mortality of 16%.
The ability of both essential oils of Lippia spp. to paralyze the adults and kill them make these essential oils a new suitable tool for the control of adults of this insect pest in small storages.
Keywords: Acanthoscelides obtectus, Phaseolus vulgaris, Essential oils, Lippia origanoides, Lippia alba
References:
[1] Pavela R. Insecticidal and repellent activity of selected essentials oils against of the pollen beetle, Meligethes aeneus (Fabricius) adults. Ind. Crops Prod. 2011, 34: 888-892.
[2] Papachristos DP, Karamanoli KI, Stamopoulos DC, Menkissoglu-Spiroudi U. The relation between the chemical composition of three essential oils and their insecticidal activity against Acanthoscelides obtectus (Say). Pest Manag. Sci. 2004, 60: 514–520.