Efficacy of Selected Insecticides and Botanicals in the Control of Field Insect Pest of Okra (Abelmoschus Esculentus) in Akure

Okra (Abelmoschusesculentus (L) Moench) is one of the most widely grown and consumed vegetables.It forms an essential part of diet for its calcium and iodine contents as well as the mucilaginous properties of its fruit.Okra is also a good source of vitamins A, B and C. Okra is also a potential candidate as a biodiesel feedstock.The crop is battled with pests.Oladimeji et al. (2010) described the flea beetles as the most injurious insects on okra.Flea beetles are presently being controlled with insecticides among which lambda-cyhalothrin (Karate), a synthetic pyrethroid is known to be effective.However, the associated problems of synthetic insecticides have called for a renewed interest in the botanicals.Also, consumer demand for organically produced foods is on the increases and scientific research on the use of botanical pesticides is now gaining momentum (Nas, 2004).This research work evaluates the efficacies of commonly used organophosphorus (Chloropyrifos), carbamate (Carbofuran), synthetic pyrethroid (Lambda-cyhalothrin) and the potentials of aqueous extracts of three botanicals obtained from seeds of Azadirachtaindica, Piper guineense and Allium sativumpaste in the control of insect pests of okra.The specific objectives are to assess the level of insect pests infestation on okra in response to the various insecticide treatments; to determine the efficacy of the selected insecticides and botanicals in the control of insect pests of okra; and to determine the separate and combined effects of the botanicals under study in the control of insect pests on okra. MATERIALS AND METHODSThe research was conducted at the Experiment Station of the Department of Crop, Soil and Pest Management of the Federal University of Technology, Akure in the 2014 early raining season.The site lies roughly between latitude 7 0 16 1 northand longitude 5 0 12 1 east of Greenwich meridian.It is in the rainforest zone with alfisol soil type.The rainfall pattern is similar to that of any humid tropical climate, characterized by two peaks.The experimental site was ploughed twice with a two-week Abstract: A randomized complete block field experiment was conducted to evaluate the insecticidal efficacy of selected synthetic insecticides and botanicals for the control of insect pests of okra (Abelmoschus esculentus) L Moench at the Teaching and Research Farm of The Federal University of Technology, Akure (70 16'N, 150 12'E).The experiments consisted of four rates (50, 75, 100, and 125%) of lambda-cyhalothrin, dichloropyrivos and carbaryl and two extraction methods comprising of hot and cold extracts of Piper guineense, Allium sativum and Azadirachtaindica including their mixtures.The treatments were sprayed twice and thrice while assessments of insecticidal efficacy based on Henderson Tilton formular was conducted at 2, 4 and 6 week after treatment application.Insect counts were collected and percent efficacy calculated.Result obtained shows that there was a general decline in insect population as the insecticide application continued and all the biocides were significantly (P<0.05)toxic to the flea beetles than the control.Carbaryl performance exceeded all other insecticides in the parameter measured.Although the performance of the botanicals is not as good as synthetic insecticide, it was better than the untreated control plot.It is concluded that A. indica, P. guineense and A. sativum (in order of importance) can be used as an alternative to the synthetic insecticides tested in this study for the control of flea beetle and other insect pests on okra.