Adesina J.M. , Afolabi L.A.

1. Department of Horticultural Technology, Rufus Giwa Polytechnic, P.M.B. 1019, Owo, Ondo State, Nigeria
2. Dean’s office, Faculty of Agricultural Technology, Rufus Giwa Polytechnic, P.M.B. 1019, Owo, Ondo State, Nigeria
Author    Correspondence author
International Journal of Horticulture, 2014, Vol. 4, No. 2   doi: 10.5376/ijh.2014.04.0002
Received: 03 Dec., 2013    Accepted: 26 Dec., 2013    Published: 03 Jan., 2014

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.

Adesina et al., 2014, Comparative Bio-Efficacy of Aqueous Extracts of Loncarpous Cyanescens and Trema Orientalis Against Flea Beetle (Podagrica Spp) (Coleoptera: Chrysomelidae) Infestation And Yeild of Okra, International Journal of Horticulture, 2014, Vol.4, No.2 4-9 (doi: 10.5376/ijh.2014.04.0002)

In Nigeria, Okra (Abelmoschus esculentus) is attacked by two flea beetle species, Podagrica uniforma (Jaq.) and Nisotra dilecta (Jaq.) (Coleoptera: Chrysomelidae) which are responsible for heavy defoliation and causes significant yield losses and synthetic insecticides with its attendant problems is currently be employed for insect pest control. A field experiment was conducted at the Teaching and Research Farms of Rufus Giwa Polytechnic, Owo, Ondo State between June – August, 2013, to investigate the insecticidal potentials of Loncarpous cyanescens and Trema orientalis against flea beetle infestation on okra in Randomised Completely Block Design (RCBD) and treatments replicate three times. Synthetic insecticide (Lambda cyhalothrin) was used as check to compare the effectiveness of the plant extracts. Crude aqueous extracts of each plant was prepared by pounding 1 kg of plant leaves using mortar and pestle and soaked in 4 litres of cold water for 24 hours, sieved using muslin cloth. Spraying of okra plants were carried out at 5 spraying regimes beginning from crop establishment (4 weeks after planting (WAP) to harvesting period (50 days after planting (DAP) at weekly intervals using Knapsack 15 L sprayer under fairly calm weather condition. To assess the effect of the plant extracts and on the flea beetles; variables assessed included number of beetles were counted a day before treatment application, number of beetles post application of treatment and number of fresh fruit, fruit length and weight on 5 randomly selected plants per plot. Data collected were subjected to analysis of variance (ANOVA) and treatment means were separated using Least Significant Difference at 5% probability level. Results obtained shows that at 40 and 50 DAP i.e. at 4^th and 5^th spraying regimes, plot sprayed with L. cyanescens and T. orientalis extracts caused significant beetles infestation suppression (P<0.05) and not significantly different (P<0.05) compared to synthetic insecticide when compared. Plot control with L. cyanescens extract recorded the highest number of harvested fresh fruits (34.7) and fruit weight (0.78 kg), while T. orientalis extracts had 24.0 fresh fruits and longest fruit length (21.5 cm) and synthetic insecticide had the least number of fruits (22.0) and fruit length (18.7cm). Statistically, yield recorded from okra plant protected with plant extracts was significantly higher (P>0.05) compared to synthetic insecticide control plots. In light of the foregoing, it is evident from the study that the plant evaluated possess insecticidal properties which could be exploited as bio-insecticide as alternative to synthetic insecticide in the control of Podagrica uniforma (Jaq.) and Nisotra dilecta (Jaq.) infestation under organic okra production.

Heavy defoliation;Insecticidal potentials; Spraying regimes; Suppression; Synthetic insecticide