FARM PESTS 47 



headings. The first serious pest is the Turnip Saw-fly 

 {AtJialia spinarum). This is a small brown insect related 

 to the Wasp tribe, and measuring about f inch across 

 the wings. The damage done consists solely in the 

 voracious habits of the larvae or *' niggers," which 

 may be instantly known by their dark colour, numerous 

 legs and curious habit of curling themselves about 

 in various attitudes as they feed. They are barely 

 an inch long when full-grown. The final stage takes 

 place in the soil, the white pupa being enclosed 

 within a brown pupa-case. Eggs are laid by the females 

 during May and June. They make small incisions in 

 the soft parts of the leaf by means of their saw-Uke 

 weapons, and one egg is placed in each slit, with a 

 drop of irritant fluid which excites the sap towards that 

 portion of the leaf and thus affords the young saw-fly 

 sustenance. They come out on to the surface when full- 

 grown and appear as shown in the sketch. In a bad 

 case the only cure is to plough in deeply when the pest 

 is half-grown. On a small scale, however, syringing 

 with tobacco-water is recommended. (See Plate 10.) 



There are three outstanding offenders among beetles 

 which make turnips and swedes generally their place of 

 business and convalescent home all in one. These are, 

 in their order of demerit, the wretched Turnip Flea or 

 Hopper {Phyllotreta nemorum), the Turnip Gall Weevil 

 (Ceuthorhynchus pleurostigma), and the Turnip Mud Beetle 

 {HelopJwrus rugosus). The first two divide their atten- 

 tions amongst the various cruciform plants, and the 

 third confines itself to the turnip only. I shall have to 

 deal with the Turnip Gall Weevil under cabbage pests 

 in the next chapter, as it is responsible for the kind of 

 injmy wrongly called club root, so we will take the Flea 

 here and see how best we may induce him to " hop it." 



This insect is barely an eighth of an inch long, blue- 

 black or green-black in colour, and it causes immense 

 injury in some years by eating off the seed leaves as soon 



