278 CULTURE OF FARM CROPS. 



When the weevils appear in large numbers, they soon clear 

 the fields of green. The only curative process which, 

 although attempted, will also be too frequently curative in 

 name merely is to brush the surface of the young plants 

 with a light seed or bush harrow when the dew is on them, 

 so as to bring the soil in contact with the leaves ; a soiled 

 or dirty leaf the weevils will not touch. The same effect 

 may also be obtained by broadcasting dried road-detritus 

 mixed with coal-ashes, soot, or with lime. 



77. When the leaves are fairly developed, they are 

 often attacked by the larvae of a minute fly, the presence 

 of which is indicated by little " faded patches, with a 

 minute brown speck in their centres." The fly is the same 

 as that which is one of the scourges of the turnip crop, the 

 Phytomoza nigricornis, and the larvae of which feed upon 

 the fleshy parts of the leaves. 



78. Should the pea still succeed in passing through these 

 ordeals, the nature of which we have described, and get 

 into the flowering stage, it is here again subjected to the 

 attacks of what is properly called the louse, but scientifi- 

 cally the Aphis pisi, the colour of which is green that of 

 the Aphis fabce, or bean louse, being black. The same 

 remedy so efficacious in the case of the bean cutting off 

 the head of the plant is, from the nature of the plant, 

 not admissible in the case of the pea. Of preventive mea- 

 sures, then, which are all that are left to the farmer for 

 this disease of the crop, many have been proposed. Salt 

 is said to be the best, but it requires to be used with great 

 judgment. Soot also is recommended by some. 



79. If, in spite of all these enemies, the pea-stalks 

 should get the length of being podded, the pods themselves 

 form receptacles for the larvae of certain fly scourges. And 

 as the pea itself progresses in growth, it is attacked, or 

 liable to be attacked, by the caterpillar of the moth Tortrix 

 pisana; so that when thrashed out they present the worm- 

 eaten appearance which is as much dreaded by the farmer 

 as the full, plump, sound sample is cherished by him. 

 Should he be fortunate enough to have a good sample of 



