STORAGE PEST OF MAIZE

BY

DENNIS OWUSU BOATENG (TECHNICAL OFFICER)

BUNSO COCOA COLLEGE
0240296835

•      Stored maize is susceptible to infestation by insect pests and attack by diseases and can also be damaged by rodents and birds. 

•      It is important to fumigate or periodically expose grain to the sun to kill storage insect pests such as the lesser grain weevil.

•      Cleaning of the grain store to remove all traces of previous crop, preferably by disinfecting the structure before use, is important.

•      It is also necessary to monitor the condition of the stored grain throughout the storage period for insect pests, disease, temperature and moisture.

Sitophilus oryzae (Lesser grain weevil)

•      Insect description

–     Adults are 2 to 3 mm long, with a long snout and four reddish spots on the wing covers.

–     The larvae spend all their time inside the grain.

•      Damage

–     Management of this insect is very important.

–     The larvae chew large irregular holes in the kernel and when adults emerge they make an irregular shaped hole about 1.5 mm in diameter.

Tribolium castaneum (red flour beetle)

•      Insect description

–     Adults are reddish brown with a flat, oval body 2.5–4.0 mm long with wings.

–     Larvae are mobile in the grain sample.

•      Damage

–     Larvae prefer feeding on the grain germ.

–     Damage is particularly serious in grains such as rice and wheat, which have either been dehusked or processed into other products.

–     When infestation is severe, these products turn greyish-yellow and become mouldy with a pungent odour (CPC 2000).

Oryzaephilus surinamensis (saw-toothed grain beetle)

•      Insect description

–     Adults are 2.5 to 3.0 mm long, with a slim, grey body with distinct ridges on the thorax and teeth-like projections on each side.

•      Damage

–     Adult beetles of O. surinamensis can be seen moving rapidly over stored food, but the immature stages are inconspicuous (CPC 2000).

–     They are a major pest of stored grain and milled products, as they can easily eat through packaging.

Araecerus fasciculatus (areca nut weevil)

•      Insect description

–     This is a fungus weevil that is a mottled dark brown all over its 3- to 5-mm long body.

•      Damage

–     Maize is a primary host of these grain-boring insects. Infestation may cause stored grain to be hollowed out or tunnelled by the larvae.

–     Adults bore circular holes when they emerge from the grain.

–     Adult feeding causes irregular ragged patterns of damage, particularly if feeding occurs on a commodity previously damaged by larvae (CPC 2000).

Controlling Storage Pest

•      The best form of controlling storage pest of maize is by Fumigating with Phosphine.