Oryzaephilus mercator
Oryzaephilus mercator, The Merchant Grain Beetle
Oryzaephilus mercator, the merchant grain beetle, is a major pest on oil seeds, such as groundnut, melon, palm kernels and sunflower seeds.
The Merchant Grain Beetle also causes damage to dried fruit and less frequently processed cereals. It is widely distributed and often infests locations in tropical regions and other warmer climates. This species does not survive well in cooler temperatures.
The merchant grain beetle prefers to feed on damaged grain. Despite this, it is capable of damaging intact grains.
Adult Oryzaephilus mercator- Merchant Grain Beetle
(Image full credit to USDA-ARS-GMPRC)
Biology of Oryzaephilus mercator, The Merchant Grain Beetle
Life cycle of the merchant grain beetle.
The adult is flattened in appearance with a red-brown colour, and around 2.5mm in length. Adults live an average of 6-10 months but have been known to live longer. Mature females can produce between 43 and 285 eggs every 28-42 days. The eggs are microscopic, white and elongated.
Larva Oryzaephilus mercator, Merchant grain beetle
(Image full credit to USDA-ARS-GMPRC)
The larva feed by burrowing into grain kernels. The merchant grain beetle exists in larval form for 2 weeks. It then pupates for a week before emerging as an adult. When they reach adulthood they develop wings, and can fly to infest facilities which were not previously infested. It takes around 35 days in optimum conditions for the life cycle of egg to adult to complete.
Pupal stage of Oryzaephilus mercator, Merchant grain beetle
(Image full credit to USDA-ARS-GMPRC)
Damage Caused by Oryzaephilus mercator, The Merchant Grain Beetle.
Damage caused by Oryzaephilus mercator to produce includes a reduced dry weight and quality of stored oilseeds and nuts. Water content increases within the environment sustaining the insects which is known to encourage fungal growth on remaining products, further damaging the stock. Other contaminations caused by these insects include the larval moults which have been shed during growth, and possible dead adult insects.
Adult Oryzaephilus mercator- Merchant grain beetles, infesting processed cereal
(Image full credit to Royal Alberta Museum)
Pheromone trap for Oryzaephilus mercator, The merchant Grain Beetle.
Russell IPM manufactures and supplies a complete monitoring system, Xlure-MST for Oryzaephilus mercator. This trap can be used to assess the severity of an infestation of Oryzaephilus mercator before it becomes serious. It can also be used to monitor the effectiveness of any control measure being used to treat an infestation of Oryzaephilus mercator. The Xlure-MST is a multispecies trap based on insect pheromones and food lures.