ABSTRACT

 The emergence of biodegradable pesticides as safe option has reduced the problems that result from the use of synthetic insecticides, thus creating a renewed interest in their development and use in integrated pest management of crops. 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. The experiment was conducted between 7th June 2017 to August, 18th, 2017 within the premises of Federal Ministry of Agriculture and Rural development Umuahia, opposite timber market along Ikot Ekpene express road Umuahia. Seeds of Abelmoschus esculentus (okra) were gotten from a local market in Umudike in Umuahia. Freshly harvested leaves of Vernonia amygdalina and Chromolaena odorata, were room dried and grinded into a powdery form. During application, the grinded leaves are soaked in water (21itres of water) for about 12 hours and sieved before application. The wood ash was applied on the plants ecologically (by hand spraying), 10ml of the synthetic chemical was collected using a syringe and was mixed with 2 litres of water before application. The mixture comprising of 2 litres of water, 2grinded pepper, 2g of aerial detergent, 2 tablespoonful of kerosene were also mixed together before application. Results show the presence of phytochemicals in V. Amygdalina such as terpenoids as the highest phytochemical present followed by tannins, steroids, alkaloids, phenols, flavonoids and saponins while C. odorata recorded saponins as the highest phytochemical present. This is followed by phenols, tannins, and alkaloids while steroids and terpenoids are close in range. According to the planting and randomized distribution of the insecticidal plants in the plots, block 1 had C. Odorata and V. Amygdalina at a close range occupying plots 1 and 2, respectively. This block showed highest insecticidal activity as evident in the results ofthe morphological and yield parameters which include number ofsprouts, leaves, openings, leaf area, percentage yield as well as fresh and dry weight ofthe yields. The physicochemical properties of the soil with BS having the highest percentage which was followed by sand at a close range. Silt clay and pH were recorded. Some minerals also identified in the soil include phosphorus, P, organic carbon, OC and organic matter, OM. Other physic-chemical properties (Cmol/kg) as recorded in fig. 8 are as follows: calcium, magnesium, potassium, sodium, exchangeable acidity, EA and ECEC. From this work, it was observed that C. odorata and V. Amygdalina possess some phytochemical compounds which are needful and necessary for humans and studies have also shown that some ofthese phytochemicals are applied by the plants in defence mechanisms and as such having some pesticidal activities of which C. odorata and V. Amygdalina are typical examples. Their ability to wade off okra insects was made manifest in the morphological characteristics and this is likely due to the strong synergistic activity of both plants.