Rhyzopertha dominica, the Lesser Grain Borer.
The Lesser Grain Borer, Rhyzopertha dominica is a serious stored grain pest of corn, cocoa, nuts, tobacco, beans and other stored grain. This insect originated on the Indian subcontinent and now widely distributed all over the world. Rhyzopertha dominica damage is more severe in warm dry conditions but they are found in temperate regions. Both adults and larvae bore into the grain and hollow it out leaving only a husk. Infestation of Rhyzopertha dominica significantly reduces the market value of infested grains.
Frontal view of Rhyzopertha dominica, the lesser grain borer.
(Image full credit: Simon Hinkley and Ken Walker, MuseumVictoria)
Biology of Rhyzopertha dominica, The Lesser Grain Borer.
Rhyzopertha dominica, The lesser grain borer, pupa
(Image full credit: USDA, Agricultural Research Services)
An adult Rhyzopertha dominica is a dark brown to black grain borer which grows up to 3mm in length. Females lay eggs singly or in clusters of around 20, and a total of around 500 in lifetime. These eggs will hatch within 2-4 days. The larvae of the lesser grain borer are white with C shaped bodies. The lesser grain borer will stay at the larval stage from 27 - 46 days. The pupal stage is typically within the damaged grain husk hollowed out during the larval stage. Pupation usually lasts around a week before mature Rhyzopertha dominica emerge. The adults lifespan can reach 240 days. They are strong fliers and may fly to other areas within 1000m of original site and create new infestations.
Life cycle of The Lesser Grain Borer, Rhyzopertha dominic
Nature of Damage, Rhyzopertha dominica, The Lesser Grain Borer.
As a primary stored grain pest they pose a severe threat to wholegrain stores, they can bore into the grain and eat a substantial amount. It is reported that the essential amino acid content of grains is reduced during an infestation of this insect. Infestations of Rhyzopertha dominica are accompanied by an unpleasant odour and the grain is contaminated with shed skins, uric acid and the bodies of deceased adults. Grain spoiled by these organisms is not fit for use as the mass and quality are drastically reduced. Rhyzopertha dominica infestations can facilitate invasion of a secondary stored product pests such as flour beetles and fungi.
Adult Rhyzopertha dominica, lesser grain borer, on damaged wheat husk.
(Image full credit: Clemson University - USDA Cooperative Extension Slide Series)
Pheromone traps for Rhyzopertha dominica, The Lesser Grain Borer.
Russell IPM manufactures and supplies a complete monitoring system, Xlure-MST for Rhyzopertha dominica. This trap can be used to assess the severity of an infestation of Rhyzopertha dominica before it becomes serious. It can also be used to monitor the effectiveness of any control measure being used to treat an infestation of Rhyzopertha dominica. The Xlure-MST is a multispecies trap based on insect pheromones and food lures.