Pesticides and Food safety in Africa – A review

Abstract

African countries have experienced rejects and other forms of embarrassment in international trade from the importing countries of their agricultural produce based on the presence of pesticides at levels above the set global limits. Not a few of the infractions were a result of incorrect ways of pesticide application and the nature of the chemical structure. This leaves open a window of biological alternatives which this review article seems to explore.

Keywords: pesticides, food security, human health, green,  africa

INTRODUCTION

With an annual growth rate of 1.2%, the world population is estimated to reach 9 billion by 2050 (Godfray et al., 2010 and Carvalho, 2006). United Nations (UN) estimates, indicate that 95% of this increase in world population will occur in the developing countries and regions such as sub-Saharan Africa (UN 2001, 2005), hence the need to step-up food production through increase in agricultural productivity. In Africa, crop losses caused by pests and diseases are two major barriers to increase in agricultural produce. This has led to the overzealous application of agrochemicals or pesticides to farm crops and this in turn has brought its own set of problems both to the farmers and the environment (Nnamonu and Onekutu, 2015). Pesticides are chemical substances used to kill, repel or control pests or used to prevent the damage the pests may cause. They are commonly used to control a variety of agricultural pests that are likely to damage farm crops and livestock, leading to a substantial reduction in farm productivity. Initially, with little insight into the long term effect, pesticides use seemed to be a success, until the incidence of resistance. Hitherto, easily controlled pests became uncontrollable leading to application of higher amounts to ensure effectiveness. agriculture, pest infestation have been identified as a major threat worldwide and a source of crop diseases and losses (Cook, 2017). The first record of the use of insecticides was 4,500 years ago, when sulphur was used by the Sumerians to control insects and mites.  Other chemicals and heavy metals such as mercury, arsenic, tar, copper, sulphate, and lime have been used to prevent pests and protect crops. By 1940, Sodium Chlorate and Sulphuric acid were in use and in the late 1940s synthetic pesticides such as DDT, BHC, Aldrin, Dieldrin, Endrin, Chlordane, Parathion, Captan, and 2,4 –D were developed and widely used. These new products were cheap, effective and generally accepted. However, in 1962, the problems and danger of the indiscriminate use of pesticides to the environment was highlighted. Even when many African countries are familiar with, and possibly signatories to many global initiatives like FAO code of conduct on distribution and use of pesticides, Codex, Cartagena Protocol, Montreal Protocol, Stockholm convention, needless application leading to environmental pollution and the concerns about health of living organisms still subsists. Reasons for these include inadequate expertise(Sithole and Sauyama, 2003) conscious use of obsolete pesticides(Shiyelekeni, 2000) and different monitoring capacities that vary from one location to another (Mutengwe et al., 2016). In South Africa, according to Mutengwe et al 2016, the implicated pesticides that exceeded established MRLs were imazalil (37.71%), prochloraz (28.69%), and iprodione (5.74%). The unregistered pesticide most often found on grapes and avocados was also imazalil (62.23%) and, on nectarines and avocados,diphenylamine (11.15%) and the exceedances of MRL values involved oranges (43.44%), avocados (27.87%),grapefruits (7.38%), and lemons (6.56%).

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