78 DISEASES OF CROPS. 



and, when they turn to perfect insects, they eat their way 

 out of the now dried and puffed-out skins of the aphides. 

 (2) Another enemy of this and other aphides is the blue- 

 tit {Parus cceruleus). This little bird and the titmice 

 generally are without doubt the friends of the farmer. 

 Mr. W. Swaysland {Familiar Wild Birds) says : " The 

 number of obnoxious pests destroyed in one day by a 

 blue-tit must be very considerable, and it is to be re- 

 gretted that due importance is so seldom attached to this 

 fact by gardeners and other individuals who wage war 

 against it, merely regarding it as a nuisance and a de- 

 predator." (3) Good cultivation and a liberal supply of 

 manure (artificial as well as natural) are means of pre- 

 venting the attacks of this pest. 



Cure. — Dressings of lime, soot, or soot and lime, whilst 

 the crop is young, are means of destroying Aphis granaria. 



The Ribbon-footed Corn Fly {Chlorops tceniopus, 

 Fig. 32)1 attacks barley and wheat crops, but more par- 

 ticularly the former. '' Plants affected by Chlorops are 

 easily detected. Generally, the ears are not free as 

 healthy ears, but are enwrapped still in the sheathing 

 leaves. Little yellow maggots may be found near the 

 nascent ears, sucking out the juices of the plant. "When 

 these injured ears get out of their sheath, or are stripped 

 of their sheath when the plants are ripening, a destructive 

 furrow is seen from the base of the ear to the internode 

 (Tig. 32 D). In this furrow the larva changes to a pupa." 

 Affected plants are shorter than healthy ones, " their 

 stems are stouter and the joints are frequently swollen, 

 or ' gouty ' in fact." 



The fly (Fig. 32 A) is of a yellow colour with brown 



1 " Gout fly," " Haulm fly," etc. 



