Scholarly Journal of Agricultural Science Vol. 3(2), pp. 62-65, February, 2013 Available online at http:// www.scholarly-journals.com/SJAS ISSN 2276-7118 ©2013 Scholarly-Journals
Full Length Research Paper
Effect of spray treatments on the production of an indigenous cowpea, Erusu Olotuah, O.F. 1
Department of Plant Science and Biotechnology, Adekunle Ajasin University, P.M.B.001, Akungba Akoko, Ondo State, Nigeria. Accepted 10 October, 2012
The effect of treatment applications of raw extract of neem leaves and cypermethrin on Erusu cowpea was determined. In the study, the effects of the spray treatments were determined through insect count, plant morphology and pod load. Research findings showed that despite the considerable reduced infestation and high morphological characteristics observed in cypermethrin treated plots, the pod set was significantly low compared to neem treatment and control. Thus, this local variety of cowpea had been confirmed to require no spray treatments as it could resist pest attacks. Keywords: Defence, spray treatment, indigenous cowpea, Akoko, cypermethrin, neem
INTRODUCTION Cowpea (Vigna unguiculata) (L) Walp is the second most important food grain legume in tropical Africa countries like Nigeria, Niger, Burkina Faso, Uganda and Senegal. It is mainly grown as a subsistence crop for home use in nearly all African countries. It is also grown extensively in South-East Asia and Latin America and to a limited extent in the Southern part of the U.S.A. Cowpea (common beans) is a supplementary staple food in the cities Dominic et al (2005). It is especially boiled and eaten with other dishes such as rice, yam, plantain, bread, etc. It can also be milled (after brief soaking in water) and fried in oil, with spices to form cakes or ‘akara’ balls, a common breakfast menu usually eaten with maize pap. When the bean meal is spiced, and large spoonful wrapped in leaves, then boiled in water at breakfast or supper. Cowpea stems/leaves are used as hay and silage for livestock. Cowpea is a valuable rotational crop for soil improvement. These nutrients content of the seeds are as follows: Water, 11%, protein, 23% carbohydrates, 57%, fat, 1.3% fibre, 3.9% and Ash, 3.6% (in cropproduction techniques for the tropic by Dominic et al. 2005).
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The protein in cowpea seed is rich in the amino acids Lysine and triptophan, compound to cereal grains; however, it is deficient in methionine and cysteine when compared to animal proteins. Therefore cowpea seed is valued as a nutritional supplement to cereals and an extender of animal protein. Cowpea can be used at all stages of growth as a vegetable crop. The tender green leaves are an important food source in Africa and are prepared as a potherb, like spinach. Immature snapped often being mixed with other food. Dry mature seeds are also suitable for boiling and caning. In many areas of the world, the cowpea is the only available high quality legume hay for livestock feed. Digestibility and yields of certain colures have been shown to be comparable to alfalfa. Cowpea is also used as a green-mature crop a nitrogen fixing crop, or for erosion control. Another important feature of cowpea is that it fixes atmospheric nitrogen through symbiosis with nodule bacteria (Bradyhozobium sp). Based on the extensive uses of cowpea, several species are produced through different breeding techniques, hybridization, tissue culture and locally. Cowpea varieties are attacked by a wide range of insect pests in Nigeria which had prompted the adoption of several control measures. These measures include the use of synthetics and botanicals. These different approaches have their merits but in recent years
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researches have been turning more towards selective bio-rational pesticides, generally perceived to be safer, cheaper, and more easily produced than the synthetic insecticides. Erusu cowpea is an indigenous cowpea whose name is derived from the locality in which it is produced. Erusu is located in Akoko North West Local Government Area of Ondo State, Nigeria. The people of this area are predominantly producers of this local variety of cowpea and employs local pest control mechanisms. Erusu cowpea is a peculiar breed that requires no treatment application during its growth season as it is seen to have an inbuilt Defence mechanism and/or if synthetic treatments are applied, the crop over-growths morphologically with poor pod set. Consequently, the cultivation of this crop differs in no way from the other varieties in terms of climatic, soil and other agronomic requirements. This research work was focused on the effect of treatment application of Cypermethrin on the production of this local variety of cowpea while the raw extract of the leaves of neem, Azadirachta indica was used as a natural protectant.
MATERIALS AND METHOD The study site The experiment was conducted at Ikaram Akoko a nearby village to Erusu Akoko in Akoko North West Local Government Area of Ondo State, Nigeria during the early planting season (April – June) of 2011. The field experiments according to Olotuah and Ofuya, 2010 consisted of five blocks each measuring 2.1 m wide by 11 m long and consisting of three main plots corresponding to treatments. Planting distances were 80 cm between rows and 25 cm within rows. The plots were planted in randomized block design. Collection of samples The seeds of the local cowpea, vigna unguiculata (L) WALP var. Erusu were collected from Erusu Akoko, Ondo state. Preparation of A. indica Raw extract of fresh leaves of Neem, Azadirachta indica at a concentration of 10% (1.0 kg soaked in 10 litres of water) was prepared as botanical spray treatment. Preparation of cypermethrin The spray of Cymbush 10EC which contains 100 gm Cypermethrin per litre was done at a recommended reduced dosage of 25 ml in 20 litres of water in a full load of a conventional knapsack CP 20 sprayer. Spray treatments were applied fortnightly and terminated at
eight Weeks after Planting. Natural infestation of experimental plots by the insects was not monitored. There was a control experiment with no treatment application. Evaluation of Trial The evaluation of efficacy of the treatments was determined by: a. Insect count Assessment. This was determined by counting in situ the total number of insects found on the total plot. b. Yield and Yield component assessment: This was determined at maturity by selecting 10 pods randomly from each experimental plot with different spray treatments. The pods were weighed and measured for successful pod production through count as Pod Load. Data Collection and Analysis All data were subjected to Analysis of Variance (ANOVA) and means compared for significance differences using Least Significance Difference (LSD) values at the 5 % level of probability of Tukey’s Honestly Significance Test. Counts were normalized by square root transformations ½ (x + 0.5) before analysis.
RESULTS AND DISCUSSION Erusu cowpea at its natural state is very healthy, resistant to disease and have good yield. The application of Cymbush 10EC which contains 100 gm Cypermethrin per litre reduced significantly insect infestation with concomitant high pod weight but reduced pod load. This improved morphological qualities resulting from spray treatment application corroborates the view of “Olatokunbo et al, 2008” in the antifungal and allelopathic effects of extracts of Zingiber officinale on growth parameters of Cowpea (Vigna unguiculata, Walp). It has equally been reported that cypermethrin will control a wide range of insect in a wide range of crop. When it acts as a stomach and contact insecticide, it begins work immediately upon contact or ingestion, leading to insect knockdown and death. It also acts as a high-power poison to the central nervous system in which once poisoned the insect nerve becomes excited, causing paralysis and preventing normal feeding and growing activities lead to insect death. This is similar to the performance of cypermethrin used in this study where it acted as a protectant against insect pest population growth by reducing the damage rate of the pest leaf, flowers, stem leading to improved morphological development of the crop. Disappointingly, this protective tendency and improved morphology had not translated into improved high pod set
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Table 1: Cumulative Means of Parameters of Cowpea in the field experiment
Treatment Neem Cymbush Control
Mean Insect Count 5.70± 0.1b (32) 3.67± 0.1c (13) 6.75± 0.1a (45)
Pod Weight (g) 1.5±0.1b 2.3±0.1a 1.2±0.1c
Pod Load 17.96± 0.2a (322,10.73) 3.54± 0.1c (12,0.4) 16.97± 0.2b (283,9.43)
Means in each column bearing the same letter are not significantly different at the 5 % level of probability by Turkey’s test. Values in parenthesis are cumulative counts and means
as this is a peculiar situation in this indigenous cowpea variety contrary to other cowpea varieties. Furthermore, Erusu cowpea sprayed with aqueous extract of Neem, Azadirachta indica produced pods significantly different, P>0.05, in weight and insect infestation compared to synthetic treatment and control which corroborates the efficacy of other botanicals as field and storage treatments, Table 1. In Nigeria the biological efficacies of powders from a few plants such as seeds of neem tree, Azadirachta indica A. Juss., dry flower buds of clove, Eugenia aromatica (L.) Baill., dry fruits of West African brown pepper, Piper guineense Schum and Thonn, dry seeds of “pepper fruit” tree, Dennetia tripetala Baker, and dry bark of the “tooth ache” plant, Zanthoxylum zanthoxyloides (Lam.) have been investigated and confirmed by many workers ; Adedire and Lajide, 2001; Ofuya and Salami, 2002; Boeke et al., 2001; Ofuya et al., 2010). Also, Tapondjon et al. 2002, showed that the dry grounded leaf of Chenopodium ambosioides inhibited F1 progeny production and adult emergence of the C. chinensis and C. maculatus and Kim et al. (2003) showed the potent insecticidal activity of extract from Cinnamon (Cinnamomum cassia) bark and oil, horseradish (Cocholeria aroacia) oil, and mustard (Brassica juncea) oil against C. chinesis, within one day after treatment. Consequently, Olotuah (2003) reported that the use of Cashew Nut shell liquid is effective in the control of Okra field insect pests, Podagrica uniforma and P. sjostedti). The protection by Cypermethrin had been reported to be due to the presence of some active compounds such as insecticide (pyrethroid ester insecticide) acaricides (pyrethroid ester acaricides) and nimbolide and 28 – dexonimbolide. In the same vein, the efficacy of Neem had been attributed to the presence of azadirachtin which is the principal active compound in the leaf and has also been confirmed to repel pests by acting as an antifeedant, and so disputes insect growth and reproduction thereby reducing insect damage to cowpeas. This study on the effect on spray treatment on the indigenous cowpea, Erusu showed that Cymbush and Neem extract had a great improvement on its morphological development. Although the reduced pod load in cypermethrin application could be attributed to over-dosage which calls for a review of its recommended dosage application and also the improved performance with the recommended application of neem is equally an indication that the indigenous cowpea must be endowed
with in-built Defence mechanism and requires little or no treatment application. The control of field pests as observed in the two spray treatments and concomitant improvement in morphology had opened new vistas of approach to crop protection.
CONCLUSION The findings in this study indicate that Erusu cowpea in its natural state is healthy and has high insect resistant capability. The research tends toward finding a more reliable control measure which involves the adoption of a similar and indigenous cowpea variety which appears to be endowed with an in-built Defence mechanism and requires no spray treatment. As such, this indigenous cowpea variety could be cultivated and the active ingredients extracted, formulated and packaged after the convincing findings. Thus, the research would fulfill the dream of providing more ecologically tolerable control measures of pest management using formulated plant extracts and as such promote the importance of intensified plant protection programs as a means of increasing productivity to feed the world's growing population. ACKNOWLEDGEMENT This research will be incomplete without mentioning the contributions of peasant farmers at Ikaram and Erusu Akoko for their information, provision of viable seeds and land for the cultivation of the indigenous cowpea variety. REFERENCES Adedire, CO,Lajide, L ( 2001). Efficacy of powders of some tropical plants in the control of the pulse beetle, Callosobruchus maculatus (F.) (Coleoptera: Bruchidae). Applied Trop. Agric. 6:11 - 15. Boeke, SJ, van Loon, JJA, Van Huis, A, Kossou, DK, Dicke, M (2001. The use of plant material to protect stored leguminous seeds against seed beetles: A Review. 108 pp. Backhuys Publishers, The Netherlands. Dominic, J, Udoh, BA, Asequo,NU (2005). Crop Production Techniques for the Tropics. J. of Stored Products Res. 37: 216-217. Kim, SI, JY, Roh, DH, Kim, HS, Lee, Ahn, YJ (2003). Insecticidal activities of Aromatic plant extracts and essential oils against Sitophilus oryzae and Callosobruchus chineensis Journal of Stored products Research 39(3): 293-303. Ofuya, TI, Olotuah, OF, Akinyoade, DO, (2010): The Effect of storage
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on the Efficacy of Eugenia aromatica (Baill.) in the control of Callosobruchus maculatus (Fabricius) pest. J. Appl. Sci. Environ. Manage. Vol. 14(1) 97-100. (Nigeria) Ofuya, TI, Salami, A (2002). Laboratory evaluation of different powders from Dennetia tripetala Bak. as protectants against damage to stored seeds of cowpea by Callosobruchus maculatus (F.). J. of Sustainable Agric. and the Environ. 4(1): 36 - 41. Olatokunbo, SA, Olotuah, OF, Lawanson, FO (2008): Antifungal and Allelopathic Effects of Extracts of Zingiber officinale on growth parameters of Cowpea (Vigna unguiculata, Walp). Science Research Annals, 4(2):6 – 11.
Olotuah, OF (2003). Evaluation of cashew nut shell liquid (CNSL) for the control of podagrica beetles infesting okra, Abelmoschus esculentus (L) Moench. Applied Trop. Agric. 8: 8-10. Taponjou, LA, Adler, C, Bouda, H , Fontan, DA (2002). Efficacy of Powder and Essential Oil from Chenopodium ambrostodes leaves as post-harvest grain Protestants against six-stored product beetles, J. of Stored Product Res. 38(4) 395-402.
