Sceintific Name: Ahasverus advena (Foreign grain beetle)

Common Name: Foreign grain beetle

Synonyms

Cathartus advena, Cryptophagus advena

Taxonomic Position

Class: Insecta

Order: Coleoptera

Family: Silvanidae

Genus: Ahasverus

Species: Ahasverus advena

Origin and Distribution

A. advena is more or less cosmopolitan in tropical and warm temperate regions of the world, but is most common in tropical Africa and Asia. It probably originated in America, where other species of the genus occur. It is absent in India and listed as quarantine pest in schedule VI of PQ Order, 2003.

Host Range

Oats, Barley, Rice, maize, Cocoa, Wheat, oilseeds, nuts, herbs and spices

Pest Destructive Stage

Secondary pest and mould feeder

Both larvae and adult can cause the damage. Larvae are external feeders.

Damage Symptoms

This insect does not feed on the grain itself, but on fungi. Its presence in grain is an indication of mouldy grain.

Identification features

Larvae

The larvae are white, Campodeiform, mobile and 1-3 mm in length.

Adult

• The adult is 2-3 mm long and mid-brown.
• The antennae are clubbed and moderately long.
• Antennae with gradual, three-segmented club, segment nine distinctly narrower and shorter than segment ten.
• Eyes prominent, temples short and acute, covering hind margin of eyes.
• Pronotum weakly transverse, with anterior angles strongly protuberant and side margins entire to weakly crenulate, disc very shallowly punctured.

Life Cycle

• The life cycle takes about 30 days at 30°C and 70% RH on wheat germ. A. advena does not breed when the humidity is below 65% RH and on cocoa it requires at least 80% RH.
• Adults of the foreign grain beetle are attracted to mould grains, where females deposit their eggs singly or in small clusters.
• The larvae develop through four to five larval instars in about fifteen days.
• The adults have an average lifespan of 215 to 250 days.
• The insect is a strong flyer and, from long distances, can easily locate mouldy grain in bins and in fields.

Detection methods

Samples can be examined with naked eye or under magnifying glass or stereoscopic binocular microscope and by using soft X-ray and seed transparency method hidden infestation can be detected.