Comparing the effects of crude and refined Mammea americana (Mamey apple) leaf extracts on Doralis symphyti (aphids) on ochro (Hibiscus esculentus) plants

The aphid, Doralis symphyti (Homoptera: Aphididae), a harmful pest of many crops, causes direct damage by consuming all plant parts, reducing plant vigour, and indirect damage by honeydew secretion and transmission of several viruses. Due to the problem of pesticide resistance, alternative techniques for chemical control, such as the use of natural insecticides with minimal effects on the environment and natural enemies also coincide with organic agriculture have been the objective of this research. The effects of Mammea (Mammey americana) leaf extracts on the mortality of aphids were evaluated. The mammey extracts (Crude and refined) were tested in the laboratory (bioassays) at 100%, 90%, 80%, 70% and 60% dilution. The 80% was determined to be the most efficient dilution. The refined extract resulted in 100% mortality at 84 hours while the dry leaf and green leaf extracts gave 100% mortality in 96 hours. In the field, the refined extract resulted in 65% mortality, dry leaf crude extract obtained in 43% mortality and the green leaf crude extract gave 25% mortality. The mamey leaf extracts were efficient against the aphid in the laboratory since 100% mortality was obtained for all treatments. The field study found that the green leaf extract obtained 29% mortality, dry leaf extract achieved 47% mortality and the refined extract attained 63% mortality of aphids.

MOISTURE AND ECONOMICS STUDY BY THE EFFECT OF MULCHING AND METHODS OF IRRIGATION ON OKRA (HIBISCUS ESCULENTUS L. MOENCH)

Okra (Hibiscus esculentus L. Moench) or Lady’s finger is one of the important vegetables grown throughout the tropics and subtropics. It is one of the most important vegetable grown commercially almost during the year in India. Irrigation scheduling is considered as a vital component of water management to produce higher irrigation efficiency under any irrigation system, as excessive or sub-optimum irrigation both have detrimental effects on productivity parameters of okra (Aiyelaagbe and Ogbonnaya, 1996). Mulching is effective in reducing evaporation, conserving soil moisture and has been known to modify the hydrothermal regime of soil. The result of method of irrigation is found to be non significant due to continuous rainfall. Hence, there are no differences among the methods of irrigation. Mulching with plastic sheet in okra var. VRO-6 proved the best mulch practice which produced superior growth and yield attributing characters

Performance Evaluation of Drip Irrigation Systems on Production of Okra (Hibiscus esculentus) in Southwestern, Nigeria

This study was carried out to evaluate the performance of drip irrigation systems on the production of okra (Hibiscus esculentus) in southwestern, Nigeria. Application of water to crops in an area of scarcity of water is very important to meet the food demand of the ever-increasing population and modified irrigation techniques that can assist the okra farmers to have affordable irrigation systems that will get them great yields at the end of the season was evaluated in this paper. A field experiment was conducted at the Teaching and Research farm of Agricultural and Bio-Environmental Engineering Department, School of Engineering Technology, The Federal Polytechnic, Ado, Ekiti - State, Nigeria. The field area of 150 mby 400 m was properly cleared, stumped, ploughed and harrowed. The topography of the land was flat with its suitable soil structure, texture, retention capacity and loamy clay soil. The cultivated area of land was divided into three and on each experimental plot, high yield and disease resistant okra variety seeds obtained from a research institute (IITA) were carefully selected and planted at a regular interval of 0.6 m. Drip laterals were laid in between rows of okra plants with inline drippers at a spacing of 20 cm. The parameters measured include okra seed germination, plant height, stem girth, number of leaves and yield production. The study also includes soil properties, crop water requirement and crop water use efficiency. There were no significant difference in the okra agronomic parameters at each experimental plots under drip irrigation system. The water applied to crop was greater than the actual crop water requirement and the efficiency of the drip irrigation was 68.5%. There is high in seed germination percentage in with 3.5%, 3.6% and 3.8% at each experimental plot respectively. The selected okra agronomic parameters showed that okra performed very well under drip irrigation systems. Based on the results, water application through drip irrigation has a positive impact on growth and vegetative development of okra.

Laboratory Studies on the Host Preference of Cotton Mealybug ‘Phenacoccussolenopsis’ Tinsely (Hemiptera: Pseudococcidae) in Khartoum State, Sudan

Cotton mealybug (Phenacoccussolenopsis) is a serious devastating pest which goes on a wide array of plant families. The pest spread all over the world from cool to dry hot regions. The main objective of this study was to investigate the food preference and behavior of P. solenopsis Tinseley (Hemiptera:Pseudococcidae) towards selected host plants in Khartoum State, Sudan, where a multi-choice experiment under laboratory conditions was adopted. Eight plant species were screened for attractiveness and food preference to Cotton mealybug. Where the proportions of the 1st, 2nd and 3rd nymphal instars and the adult females were recorded at 2, 8 and 24 hours after release, and compared with Chinese rose (Rosa chinensis) the control. The result revealed that the proportions of the 1st, 2nd and 3rd nymphal instars and adult females were maximum on plants of family Malvaceae, particularly the Okra (Hibiscus esculentus) followed by Cotton (Gossypium sp.) and Hambouk (Abutilon pannosum) as compared with the control. However, in contrast, the proportions were very low on unpalatable plants like Zaleya (Locally known as Raba) (Zaleyapentandra) and Eggplant (Solanum melongenaL.). However, in contrast, the proportions were very low on unpalatable plants like Zaleya (Locally known as Raba) (Zaleya pentandra) and Eggplant (SolanummelongenaL.). In conclusion, the most favorable host plants of the Cotton mealybug belonging to the family Malvaceae, while the families of Solanaceae [Egg plant (SolanummelongenaL.)] and Aizoaceae (Raba) were found to be the least preferred host plants.