Potentiality of some botanical extracts as biopesticides against the maize weevil, Sitophilus zeamais Motsch. (Coleoptera: Curculionidae)

Abstract

Laboratory studies were conducted with the aim of investigating the efficacy of some botanicals in the management of Sitophilus zeamais Motsch infesting stored sorghum. The selected plant species were Euphorbia balsamifera Aiton, Lawsonia inermis L. and Mitracarpus hirtus L. Chloroform leaf extracts of the botanicals applied at 6.25, 12.50, 25.00, 50.00 and 100.00 mgml -1 were applied to determine their effect on adult survival, concentration of total body protein and inhibition of acetycholinesterase enzyme (AChE) activity in the weevils at 30 ± 2 o C and 70 ± 5% R.H. The botanicals resulted in adult mortalities ranging from 10.00 ± 0.00 to 90.00 ± 5.77%, reduced body protein and significantly inhibited the activity of AChE in S. zeamais. The botanicals tested could serve as biopesticides in the management of S. zeamais infesting sorghum in the storage.

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“…Therefore, the use of plant materials as bio-pesticides for the control of insect pests has been considered as an indigenous pest management for reducing damage caused by pests [46,47,48] . The botanicals can be used in various forms such as powders, extracts of different organic solvents, essential oils or as dried whole plants applied as layers in between grains in traditional stores [24,35,49,50,51,52,53,54] . Researchers have been engaged in testing insecticidal activities of different plant species against the maize weevils infesting cereal grains in Nigerian stores.…”

“…There have been a lot of research efforts to investigate the potentiality of plant materials on adult mortality of S. zeamais in stored cereal grains [33,35,40,42,43,54,55,56,57,59,60,73] . It was also confirmed that some botanical extracts resulted in promising adult mortality of maize weevil in Nigeria.…”

“…When this activity is interfered, loss of coordination may likely occur, which could lead to knock-down and eventually death of the insect [78] . Halliru and Suleiman [54] reported that chloroform leaf extracts of E. balsamifera, L. inermis and M. hirtus significantly reduced the concentration of total body protein of S. zeamais and inhibited the activity of AChE in the insect body. This finding has uncovered that some botanicals have the potential of interfering with the role of total body protein and AChE in reproduction and neurotransmission in S. zeamais, respectively.…”