KEl’ORT ON ECONOMIC ENTOMOLOGY 
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Rij<l . — -The egg is wliite, cii'cular when viewed from above, liattened and radially 
striated. 
Diameter, about 6 mm. 
Larva (tig. 3). -The caterpillar varies in colour from pinkish or yellowish to dead 
white. Head brown, spiracles black. 
Lenijtli, 25-30 mm. 
Pupa (tig. 6).—The pupa is light chestnut in colour, with the intersegniental spaces 
on the abdomen yellowish. 
Leiii/th, 15-18 mm. 
Adult (tig. 1).—A stout-bodied, creamy-coloured moth, with a wing expanse of about 
30 mm. 
Thorax, abdomen, and fore-wings creamy. Hind-wings, silvery-white. T’ore-wings 
sometimes bear faint brownish markings. 
Life-history ami habits .— The eggs are deposited, frequently in batches of from three to 
five, between the sheathing leaf and the stem. On hatching, the young larva eats its way 
into the stem, and tunnels both upwards and downwards. A young plant so attacked soon 
dies, and the larva is then compelled to migrate to another plant in order to complete its 
development. 
When full-fed, it pupates in a loose cocoon composed of silk, chips and frass, usually 
within the burrow, or between the sheathing leaf and the stem. Occasionally a caterpillar 
will pupate within an earthen cell in the soil. 
The life-cycle may be completed in about six weeks. 
Where food plants are available, this pest breeds continually throughout the year. 
Effects on the crop .—-While the crop is young, numbers of the plants are killed by the 
borers. Later on in the season, they become strong enough to withstand the attack, though 
their growth is necessarily impaired. 
When the heads of corn are forming, many larv® betake themselves to them, and do 
considerable damage by gnawing the grain and fouling it with their excreta. In the case of 
dura shami, the cob becomes stunted and deformed and bears but few grains (tig. 4). 
.\ head of dura, however, being of a different construction, suffers more from fouling—the 
larva takes up its position between the head and its sheathing leaf, moisture collects, 
moulds are enabled to grow, and frequently that portion of the head becomes nothing but 
a filthy mass. 
It is no uncommon occurrence to find several larvae collected together in a single head 
of corn. 
Probably the death of a few plants at the beginning of the season has little 
effect on the ultimate yield of corn ])er feddan, but, by weakening the older plants and 
damaging the developing corn heads, the horers are responsible for a very real loss to 
the farmer. 
Preventions and remedies .—When there is no cro]) on the ground for this pest to attack, 
it passes the time either as the moth, or as the mature larva, or the pupa resting in 
the dead stalks. To keep it in check, therefore, it will be necessary to adopt several 
measures. 
When the crop is harvested, collect and burn all refuse, such as stuhble. 
When feeding the “gash ” (or straw) to stock, ensure that it is all either eaten, or so 
trampled upon that any larva3 or ])up;D contained in it must bo destroyed. 
Before sowing the main crop, plant a few “hods” of land to either dura or dura 
shami, to act as a trap crop. Moths will be attracted to lay their eggs on this, and when 
found to be infested it should he reaped, and either hurnt or fed to stock. Dura shami 
