Prostephanus truncatus is commonly referred to as larger grain borer (LGB) with reference to the related Rhyzopertha dominica, which is relatively smaller, and referred to as the lesser grain borer. P. truncatus is about 6 mm (0.24 in) long as compared to 3 mm (0.12 in) long in R. dominica. At optimum conditions of 80% relative humidity and 32 °C (90 °F), and available food, P. truncatus completes its lifecycle within 27 days. It is a serious pest of dried grains, especially maize and dried cassava in West Africa. This beetle is believed to have been introduced into West Africa through food aid from America. It reached Africa through Tanzania in the early 1970s.
Management
Prevention Resistant varieties of maize are available. In Kenya, varieties EMB 0702 for are suitable for medium altitude, and MTPEH0701 and M/0702 are suitable for the coastal region Removal and burning any plant residue from previously infested fields can be conducted to prevent P. truncatus infestation. Used sacks can be immersed in boiling water to eliminate residue infestations For cassava, infestation from the larger grain borer can be prevented by removal of any plant residue from the previous harvest if the pest is known to be in the area. Leaving cassava roots in the ground for longer reduces storage time and chances for the borer to infest. Monitoring Pheromone traps can be used in susceptible areas to monitor populations. Careful sampling and examination of grains enables detection of low infestation levels. This can be conducted by inspecting holes and cracks where adults can hide and using a box sieve with a mesh of 1 to 2 mm to separate the insects and the grains. Direct control Biocontrol methods such as the predatory beetle Teretrius nigrescens can be used to control the spread of P. truncatus . Chemical control methods can also be used to control P. truncatus. == Sources ==