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International Journal of Horticulture 2014, Vol.4, No.17, 1
-
6
http://ijh.biopublisher.ca
1
Research Report Open Access
Evaluation of the insecticidal effects of
Hyptis suaveolens
(L.) for the
management of
Callosobruchus maculatus
(F.) on two varieties of cowpea,
Vigna
unguiculata
walp
Adebayo, R. A. , Eyo, M. E.
Federal University of Technology, Akure, PMB 704, Akure, Nigeria
Corresponding author email
International Journal of Horticulture, 2014, Vol.4, No.17 doi: 10.5376/ijh.2014.04.0017
Received: 25 Jul., 2014
Accepted: 15 Sep, 2014
Published: 27 Oct., 2014
Copyright
© 2014 Adebayo and Eyo, 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
:
Adebayo and Eyo, 2014, Evaluation of the insecticidal effects of
Hyptis suaveolens
(L.) for the management of
Callosobruchus maculatus
(F.) on two varieties
of cowpea,
Vigna unguiculata
walp, International Journal of Horticulture, 2014, Vol.4, No.17 1-6 (doi
Abstract
Studies were conducted at the laboratory of the department of Crop, Soil and Pest Management, the Federal University of
Technology Akure, Ondo State, Nigeria to test the insecticidal effects of powder from the leaf of
Hyptis suaveolens
(L.) for the
management of
Callosobruchus maculatus
(F.) on Oloyin and Ife brown varieties of cowpea,
Vigna unguiculata
Walp. Five levels of
the powder,0.00, 0.05g, 0.1g, 0.2g and 0.3g per 20g of cowpea varieties were evaluated against
Callosoruchus maculatus
under
laboratory conditions of 25-28
o
C, 65-75% RH). Mortality of
C. maculatus
was assessed at 24hours, 48hours and 72hours after
treatment application. Data were taken on oviposition, seeds with and without eggs, seeds with and without holes, adult emergence,
seed weight loss and germination tests. The results from the study revealed that the percentage mortality increased significantly with
concentrations. Highest number of
C. maculatus
died in seeds treated with 0.3g of the powder. Reduced values were obtained on
treated seeds compared to the untreated and were significantly different at p<0.05. Treated seeds had fewer eggs laid, reduced
emerged adults and seeds with eggs. Similar result was also observed for seeds with and without holes. Untreated seeds germinated
better than the treated seeds and showed statistical differences. Significantly higher weight loss was recorded in the untreated seeds
compared with the seeds treated with 0.3g of hyptis powder. The results obtained in this study showed that the tested powder exerts
protectant effects on the cowpea seeds and that the powder of
Hyptis suaveolens
is a potential bioinsecticide in the management
C.
maculatus
. Therefore it is recommended that higher rates of the powder and other components such as oil, water extract and ash of
the plant should be investigated.
Keywords
Hyptis suaveolens
;
Callosobruchus maculatus
;
Vigna unguiculata
; Management
Introduction
Cowpea beetle,
Callosobruchus maculatus
(F.)
(Coleoptera: Chrysomelidae) is a cosmopolitan insect
pest of cowpea. It is a field -to-store pest as its
infestation of cowpea often begins in the field as the
mature pods dry (Huignard et al.,
1985; Sathyaseelan
et al., 2008) and when such seeds are harvested and
stored, the pest population increases rapidly and
results in total destruction within a short duration of
3-4 months (Rahman and Talukder, 2006). It
multiplies very rapidly in storage and has caused 8.5%
loss in pulses during postharvest handling and storage
in India (Ouedraogo et al., 1996). Insect infestation is
a major contributor of quality deterioration of durables
(cereals, pulses, and tubers) stored in warm and humid
climates. Considerably physical and nutritional losses
sustained in these countries are due to infestation of
stored food products by weevils, bruchids and other
insects (Narong, 2003). Apart from the detrimental
economic impact, these losses pose a major threat to
food security. Currently, insect control in stored
products relies primarily upon the use of gaseous
synthetic fumigants and residual insecticides (Isman,
2005). Synthetic chemical insecticides have proved
very effective in the control of the beetle. However,
the problems associated with chemical insecticides
such as health hazards, insect resistance, pest
resurgence, residual toxicity, widespread environmental
hazards and increasing costs of application have
directed the need for effective, biodegradable
pesticides (Talukder and Howe, 2000; Elhag, 2000).
Ofuya (2003) reported that when these chemicals are
used improperly they pose risk to man and
environment. He also argued that this is most common
among uneducated rural farmers in Africa. Plant
derived materials for the protection of field crops and
stored commodities have a long history of use against
insect attack (Golob and Webley, 1980). They have