Oviposition Deterrent and Egg Hatchability Suppression of Secamone Afzelii ( Schult ) K. Schum Leaf Extract on Callosobruchus Maculatus ( Fabricius ) ( Coleoptera : Chrysomelidae )

Abstract

The efficacy of oil extracted from the leaves of Secamone afzelii was evaluated in the laboratory against Callosobruchus maculatus infesting stored cowpea. Leaf extracts from S. afzelii were obtained through the soxhlet extraction method using methanol and hexane as the solvent. Each of the extracts was tested by exposing five pairs of adult beetles to various levels of 0.5, 1.0, 1.5 and 2.0 ml corresponding to 2.5, 5.0, 7.5 and 10.0% v/w concentrations admixed with 20g cowpea in three replications respectively, in a Completely Randomized Design (CRD). Control treatment was set along. The results showed that oviposition and percentage egg hatched were significantly (P <0.05) suppressed on seeds treated with higher treatment level of extracts. Leaf extract with hexane at 2 ml (10.0% v/w)/20g cowpea seeds was most effective in suppressing oviposition and egg hatched. Therefore, S. afzelii exhibit promising degree of oviposition deterrent and ovicidal properties and, thus, have a great potential for use as a plant-based biopesticide as an alternative to synthetic insecticides for controlling C. maculatus infestation on stored cowpea grains.

Seed preservatives properties of Secamone afzelii (Schult) K. Schum extracts on wheat grains damage and germination capability

“…The reduction in adult emergence observed in the treated grains might be as a result of the low survival rate of parent adult insect exposed to contact and fumigant toxicity, anti-oviposition, ovicidal and larvicidal properties of the tested extracts. This aligned with the findings of Tapondjou et al 2002; Adesina et al 2011; Adesina and Ofuya (2015); Adesina et al (2015a, b) who opined that the oviposition inhibition property of plant products on adult storage insects makes them laid fewer eggs and where eggs are hatched the plant products killed the larvae hatching from eggs laid on grains. Udo (2005) opined that there is a relationship between first filla adult insect emergence and parental death as well as the likely presence of oviposition restrictive.…”

“…From available literature, no scientific report of S. afzelii products as insecticide against stored wheat insect pests was documented. However, the insecticidal activity of the plant methanol and hexane extracts was effective against Callosobruchus maculatus (Adesina and Ofuya 2015). Therefore, this study forms part of the search for bioinsecticides for the management of destructive pests of stored wheat grain products against grain damage and germination capabilities with extracts of S. afzelii as the main focus.…”

Perforation index assessment of cowpea seeds against cowpea bruchid, Callosobruchus maculatus (Fabricius) [Coleoptera: Chrysomelidae], infestation using Piper guineense

“…Zabri, Kabran, Kodjo and Trabi (2009) opined that the ability of pesticidal plant products to reduce the egg laying capability by female beetles may be ascribed to the occurrence of flavonoids (Ileke, 2014). The reduction in oviposition in the extract-treated seeds compared to powder may also be caused by an extract film on the seeds which makes it becomes unsuitable for oviposition (Adesina and Ofuya, 2015). The experimental plant products significantly reduced adult emergence or progeny development in treated cowpea seeds.…”

Efficacy of Kigelia africana Lam. (Benth.) leaf and stem bark ethanolic extracts on adult cowpea seed beetle, [Callosobruchus maculatus Fabricius (Coleoptera: Chrysomelidae)] affecting stored cowpea seeds (Vigna unguiculata)

“…One of the major constraints to large scale production of cowpea seeds has been the problem of insect pests ( Mailafiya et al., 2014 ; Adesina and Ofuya, 2015 ). This has led to serious economic losses both in the field and in storage ( Uyi and Igbinoba, 2016 ).…”

“…Infestation enhances a substantial reduction in grain value. Infested cowpea seeds are unattractive to consumers and usually reduce the agricultural and commercial purposes ( Adesina and Ofuya, 2015 ; Iloba et al., 2016 ). Losses caused by C. maculatus to untreated seeds falls between 40 to 100% ( Akami et al., 2017 ; Mensah et al., 2017 ).…”