Protection of cowpea,Vigna unguiculataL. (Walp.) withNewbouldia laevis(Seem.) extracts against infestation byCallosobruchus maculatus(Fabricius)

Abstract

Evaluation of protectant ability of Newbouldia laevis (Seem.) extracts against infestation by Callosobruchus maculatus in cowpea, Vigna unguiculata L. (Walp.) was carried out in the laboratory at ambient temperature of 28 ± 2°C and 70 ± 5% relative humidity. Extracts from wood ash, leaf, stem and root bark were tested at different concentrations of 0, 1, 2, 3, 4 and 5%. One hundred per cent mortality of adult beetles was achieved at all concentrations within 72 h of treatment with extracts except in wood ash at 1% concentration, but they were significantly different (p < 0.05) from the controls. All the extracts were still able to cause high beetle mortality after one, two and three months of cowpea storage at high concentrations (4 and 5%) except wood ash, although there was a slight decrease in mortality during the period of storage. All the extracts significantly (p < 0.05) reduced oviposition and adult emergence of C. maculatus when compared with the controls although the reduction was higher at 5% concentration than others. Adult beetle emergence was completely prevented at higher concentrations (4 and 5%) except in wood ash. Both oviposition and adult emergence increased during the months of storage probably because of the slight reduction in the effectiveness of the extracts. The root bark extract was much more effective in reducing oviposition and adult emergence than others throughout the period of storage. The plant extracts of N. laevis was able to protect the cowpea seeds from damage and prevent weight loss. Cowpea seed damage and weight loss was significantly more (p < 0.05) in the controls than other for the three-month duration probably because of the more adult emergence. The extracts from N. laevis did not adversely affect the germination of the protected seeds and seed germination ranged from 86.7 to 100%. It has been shown in this study that the extracts of N. laevis were effective against C. maculatus in cowpea although the root bark extract seemed to be the most effective while the wood ash extract was least effective. Their effectiveness, however, slightly decreased during the period of storage. N. laevis could be incorporated into pest management of stored cowpeas since the products are ecologically safe.

Biotoxic Efficacy of Different Fractions of <i>Acalypha godseffiana</i> Oil Extract against <i>Callosobruchus maculatus</i> Infesting Stored Cowpea

“…Also, the high mortality recorded could due to inability of the insect to feed on the seeds that have been coated with the fractions of the oil, thus leading to the starvation of the insect. The result obtained agreed with the findings of Ashamo et al (2013) and Oni (2014) in which extracts of botanicals have been found to cause mortality of C. maculatus. …”

Bioefficacy of powdery formulations based on kaolin powder and cashew (<i>Anacardium occidentale</i> L.) balms to control <i>Callosobruchus maculatus</i> F. (Coleoptera, Chrysomelideae: Bruchidae) in stored cowpea (<i>Vigna unguiculata </i>L.)

“…As soon as they were in contact with the kaolin powder, these respiratory openings were blocked thus causing the asphyxiation and the insects' mortality. Don-Pedro (1989), Ileke and Olotuah (2012), Ashamo et al (2013), andAL-Dabbagh (1993) showed that the most significant characteristic of an inert dust was its great capacity for absorption of water and the lipids. Thus the kaolin powder applied absorbed water and the lipids coming from the insect hardened body, causing its death.…”

Influence of Different Growth Media on the Morphometric Characters ofSansevieria liberica

“…Many diseases, fungi, bacteria and even insects and other pests have developed resistances to many popular synthetic drugs and pesticides [5,6]. For example, many malaria drugs are no longer effective as before Basco and Ringwald [5].…”