International Journal of Horticulture, 2018, Vol.8, No.1, 1-7
1
Research Report Open Access
Effectiveness of the Powders of
Securidaca longepedunculata
(Fres.) as
Bioinsecticides against Cowpea Beetle,
Callosobruchus maculatus
(Fab.)
(Coleoptera: Chrysomelidae)
Ojo D.O.
1
, Omotoso O.T.
1
, Obembe O.M.
2
1 Department of Zoology and Environmental Biology, Faculty of Science, Ekiti State University, P.M.B. 5363, Ado Ekiti, Nigeria
2 Department of Plant Science and Biotechnology, Faculty of Science, Ekiti State University, P.M.B. 5363, Ado Ekiti, Nigeria
Corresponding email
International Journal of Horticulture, 2018, Vol.8, No.1 doi
Received: 03 Dec., 2017
Accepted: 10 Dec., 2017
Published: 12 Jan., 2018
Copyright
©2018 Ojo et al., This is an open access article published under the terms of the Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Preferred citation for this article
:
Ojo D.O., Omotoso O.T., and Obembe O.M., 2018, Effectiveness of the powders of
Securidaca longepedunculata
(Fres.) as bioinsecticides against cowpea
beetle,
Callosobruchus maculatus
(Fab.) (Coleoptera: Chrysomelidae), International Journal of Horticulture, 8(1): 1-7 (doi
Abstract
Insect pests cause a great deal of post-harvest losses of stored food products worldwide and especially in the tropics
where food products are usually susceptible to attack by insects between the periods of harvest, storage and consumption. In the
present study, powders obtained from different parts of
Securidaca longepedunculata
(Fres.) (leaf. Stem bark and root bark) were
tested against the cowpea beetle,
Callosobruchus maculatus
in the laboratory at ambient tropical conditions of temperature and
relative humidity. The powders were applied at 0.0 (control), 0.2, 0.4. 0.6. 0.8 and 1.0 g. Insect mortality was observed for four
(days). The result obtained showed that mortality of the insect increased with increased in concentration and exposure time. The
powder obtained from the root bark recorded the highest insect mortality of 71.25 % within 96 h of exposure at the highest dosage of
1.0 g this was followed by the stem bark causing 65 % at the same level of concentration. The LD
50
revealed the root bark powder to
be the most effective as 3.17 % was required to obtain 50% insect mortality within 96 h of application as reflected by the regression
probit analysis. The
least toxic powder on
C. maculatus
was leaf powder. It was also observed that the tested powders significantly
(P<0.05) reduced oviposition and percentage adult emergence when compared with the control. The results obtained from this
research work showed that root bark of
S. longepedunculata
contains components of higher toxicity potential.
Keywords
Mortality; Lethal dosage; Oviposition; Adult emergence; Cowpea; Plant powder;
Vigna unguiculata
; Synthetic
insecticides
Background
Farmers store their products for several reasons which include (i) making food available at all times to man (ii)
making food / diet available to livestock (iii) making raw materials available to industries. Storage of Agricultural
products has been hampered drastically as a result of infestation by insect pests (Udo, 2011). As in field crops, a
wide range of insect pests attacks stored products and the commonest being beetles and moths (Udo, 2011). The
primary insect attacking cowpea seed during storage is
Callosobruchus maculatus.
The larvae bore into the seed
which becomes unsuitable for human consumption and loose viability (Taylor, 1981).
C. maculatus
is known to
cause up to 100 % loss of stored cowpea and estimates have shown that over 30 million U.S. dollar is lost as a
result of cowpea damage in Nigeria (Udo and Epidi, 2009). Infestation usually starts in the field just before
harvest and the insects’ developmental stages are carried into the stored where the population builds up rapidly
(Ilelke
et al
., 2012).
Farmers still depend on the use of synthetic insecticides in the management of stored product especially under
large scale production (Gbaye and Holloway, 2011). The continued and intensive usage of these insecticides has
produced some undesirable toxic effects on non-target biotic components of the ecosystem (Ojo and Ogunleye,
2013). Other potential difficulties associated with the continuous use of these chemical insecticides include; high
cost of procurement, pest resurgence and resistance, poisonous residue accumulation in foods and poor
knowledge of application (Ileke and Oni, 2011). To solve these problems, entomologists all over the world are in
search for botanical insecticides which are safe and environmentally friendly for the control of these insects’ pests
