CHAPTER ONE

INTRODUCTION

Background to Study

The vegetables sector in most West African countries is recovering from the shocks of policy reforms which are targeting to change the economic strategy to market oriented economy. These crop products are increasingly becoming important as produce for both local and export markets. They have a great potential to enhance the nutrition status and, thereby, health of consumers as most are good sources of vitamins, minerals and proteins needed for the proper functioning and development of the body (James et al., 2010). In Edo State, Nigeria, the government is encouraging the development of the vegetable sector in order to diversify the country’s export base (GIPC, 2013).

Among the vegetables grown, tomato is one of the most popular with high per capita consumption, used in almost every Edo State, Nigeriaian household (Asare-Bediako et al., 2007). However, crop yields per hectare are 35–50% below potential yields of 20 Mt/ha.The low yield was mainly attributed to the susceptible nature of the crop to insect pests and diseases among which plant-parasitic nematodes are one of the most prevalent (Anang etal., 2013).

Plant-parasitic nematodes have been implicated as a major constraint to tomato production (Luc et al., 2005a). Many different genera and species of nematodes are important to tomato production in Edo State, Nigeria. In many cases, a mixed community of plant-parasitic nematodes is present in farmers‟ fields, rather than a single species situation. In general, the most widespread nematode species are the root-knot nematodes (Meloidogyne spp.). The root-knot nematodes are economically important group of plant-parasitic nematodes (Perry et al., 2009). The common root-knot nematodes identified as parasites of tomatoes in the tropics are: M. incognita(Kofoid and White),M. javanica (Treub), and M. arenaria (Neal)of which M. incognitais the most important (Bridge et al., 2005).Previous studies on diversity of root-knot nematodes indentifiedM.incognita, M. javanicaand M. arenariaas the root-knot nematode species on tomato in Edo State, Nigeria (Kwara etal., 2014). Yield loss of about 20.6% in tomatoes has been attributed toMeloidogyne species (Luc et al., 2005b).The smallscale farmers on the other hand, mainly use crop rotation and weeding to control nematodes on vegetables. The commercial farmers use broad spectrum nematicides such as carbofuran and Methyl bromide to control root-knot nematodes. However, with the banning of these chemicals, alternative nematode management strategies are required.

Statement of Problem

The cropping systems used in small-scale farm conditions and in extensive field production, where the use of nematicides is either not economically viable or nonexistent, effective alternatives need to be rationally chosen for management programmes based on economics and reliability.

Organic amendments have been identified to enhance soil fertility and soil microbial populations(Changetal.,2007),aswellas suppress plant-parasiticnematodes (Bailey and Lazarovits, 2003). Therefore, it was against this backdrop that the efficacy of the different organic soil amendments was tested for their potentials in root-knot nematode management.

Research Objectives

The main objective of this study was to carry out in vitro studies in to the efficacy of citrus peels (orange, lemon and grape) control of the root-knot. The specific objectives were to:

i. assess farmers’ perception on root-knot nematodes and their management;

ii. confirm the presence of Meloidogyne spp. in the experiments using ITS- RLFPs techniques;

iii. determine the efficacy of sweet orange peels and Citrus peels as amendment in the management of root-knot nematodes in vitro and in vivo;

iv. assess the effect of sweet orange and Citrus peels on the chemical properties of the soil as well as the mycoflora and free-living nematodes in the soil;