M UZB. 13 I 



the grain, bo adult beetles, when they emerge and spread the infestation. .V 

 single grain of maize may develop up to four weevils. Development from 

 egg stage to adull stage occupies about six weeks. The aduH beetles live for 

 several weeks, feeding and laying eggs, 



Angoumois Grain Moth (Sitotroga cerealella). 



This is a small buff-coloured moth, resembling the clothes moth ; when its 

 wings are folded it measures about one-third of an inch in length. It lays 

 its eggs on the grain (of wheat as well as maize), and about sixty eggs may 

 be laid by a single female. The eggs hatch in a week, and the young cater- 

 pillar (which, unlike the weevil grub, has legs) crawls and bores into the 

 grain, eating out the interior. While still in the grain it changes into 

 a chrysalis, and thence into an adult (moth), in which form it emerges. This 

 development occupies about four weeks. To the small hole made by the 

 moth in exit there is often attached a perceptible circular lid. 



Angoumois Grain Moth (Sitotroga cerealella). 



a, eggs ; l>, lariaeal worle ; c, larva, side view ; d, pupa ; e, moth ; 

 /, same, side view. 



(After Chittenden.) 



Typical damage due to 

 Angoumois Grain Moth. 



Method of Treatment. 



To ensure that maize may remain free from insect infestation over a 

 period it may be treated in one of three ways : it may be fumigated with 

 liquid carbon bisulphide ; it may be fumigated with carbon dioxide gas, or 

 (if for seed) it may be treated with flaked naphthaline. Treatment with 

 lime, kerosene, &c, is of less value, and not to be recommended. 



Which of the methods mentioned will be the most economical will depend 

 in a measure upon the grower's circumstances, the quantity of grain to be 

 dealt with, and so on. For instance, for a small quantity of seed maize the 

 naphthaline treatment would be satisfactory, while for the treatment of grain 

 in bulk, fumigation would be the better. 



