**2. Maize**

#### **2.1 Maize production**

Maize is known to be one of the world's most important cereal crops. It has a wide genetic diversity and diverse uses which accounts for its cultivation in a vast range of agro-ecological environments. Apart from the consumption of maize by man and animals, maize is also used to produce corn ethanol and other maize products, such as corn starch and corn syrup [36].

Andean countries of South America, Mexico, Central America and the Caribbean, Africa and South and Southeast Asia are known to consume maize as human food much higher than half of its maize production. Interestingly, maize accounts for at least 15 percent of the total calories daily intake in almost all the countries in Africa and Latin America. The economy of the developed and developing countries is significantly impacted by maize production [37]. The world market has recorded an enormous growth in maize production in the most especially in countries with temperate environment where hybrids and high yielding agronomic practices are used. The main maize exporters are: United States, Argentina, France, China P.R., Hungary, Canada, South Africa. China is a relatively new exporter being the main suppliers of Asian neighbor countries. There was a prediction for developing countries by Ortiz et al. [13] that there will be a growing demand for maize alone as food to increase by around 1.3% per annum until 2020. Furthermore, another prediction by Rosegrant et al. [38] stated a double demand for maize by 2050 in the developing world, and maize is predicted to become the crop with the greatest production globally, and in the developing world by 2025.

#### **2.2 Maize losses**

Abiotic and Biotic factors (pests, pathogens and weeds) significantly contribute to grain loses and thus affects food supply. About one-third of potential crop yield is lost to pre-harvest pests, pathogens and weeds [39]. Coupled with pre-harvest losses, the losses occurring during transport, pre-processing, storage, processing, packaging, marketing and plate waste are also important. An average of 35% of potential crop yield is lost to pre-harvest pests worldwide [40].

There are different number of ways pests reduce crops productivity; their effects include, stand reducers (damping-off pathogens), photosynthetic rate reducers (fungi, bacteria, viruses), leaf senescence accelerators (pathogens), light stealers (weeds, some pathogens), assimilate sappers (nematodes, pathogens, sucking arthropods), and tissue consumers (chewing animals, necrotrophic pathogens) [41].

Post-harvest loss occurs between harvest and consumptions. The major physiological, physical and environmental causes of post-harvest losses are high crop perishability; mechanical damage; excessive exposure to high ambient temperature, relative humidity and rain; contamination by spoilage fungal and bacteria; invasion by birds, rodents, insects and other pests; and inappropriate handling, storage and processing techniques [42]. Post-harvest losses lead to high food prices thus reducing food in the market. Reducing post-harvest losses in maize is an important element in any strategic planning to make more food available without increasing the burden on the natural environment.
