Cigarette beetle, Lasioderma serricorne F (Col.: Anobiidae) is a cosmopolitan stored product insect pest (Rees, 2004). The female beetles are found to deposit about 100 eggs loosely on commodities which hatch between 6- 10 days in territory weather conditions (Cabrera, 2007). The beetles that emerge as adult are capable of flight and do not feed as adult but create holes in the product to locate a suitable oviposition site (Papadopoulou, 2006). The shortest development period from egg to adult stage is 26 days at 30°C and 70 % relative humidity (Rees, 2004) (in what product?)
The cigarette beetle is one of the most common household insect that causes damage to stored products such as dried materials of animal and vegetable origin, nuts, herbs, spices, grains and grain products etc. They usually feed heavily at the larval stage (Cabrera, 2007). The insects are also found to develop favourably on root and tuber crops such as cassava, yam, cocoyam and sweet potato mostly in the dried or processed state for storage (Adebayor, 2002). The insect usually infest and contaminates stored products with their cocoons and body parts when they die, thereby reducing the qualitative and quantitative value of the stored product which makes it undesirable for human consumption (Buss and Fasulo, 2006). The rate of development of the cigarette beetle is dependent on the food source and environmental factors such as temperature and relative humidity (Rees, 2004). The longest developmental stage is usually recorded at the larval stage where most feeding is done; the longevity of the adult insect is usually dependent on the type and quantity of food consumed during the larval stage (Papadopoulou, 2006; Mahroof and Phillips, 2008).
Tropical root and tuber crops such as yam, cassava, cocoyam, and sweet potato are major staple crops in large parts of the humid and sub-humid tropics. Sub-saharan Africa is found to produce over 50% of cassava and over 90% of the yam in the world (ref). These are mostly produced on farms usually managed by smallholders who rely on traditional, labour intensive practices that do not allow for optimal exploitation of the crop productive potential. Although the severity of production and postharvest constraints differ with agro-ecology and specific crops, all the crops suffer severe yield losses due to a wide range of pest and disease infestation (IITA, 2009).
The biology and life history parameters of L. serricorne have been investigated under various temperature and relative humidity (r.h.) conditions, generally using tobacco, yeast, wheat or spices as food sources (Jones, 1913; Powell, 1931; Howe, 1957; Lefkovitch and Currie, 1967; Mahroof and Phillips, 2008). These different food sources have been shown to influence the insect’s life history parameters. However there is paucity of data on using roots and tuber crops as food sources. There is therefore the need to investigate on insect infestation on root and tuber crops in...