BEET MOTH. 147 



caterpillars, in 1879, many were thus killed in 

 Essex. 



It was formerly difficult to apply this knowledge 

 practically ; but now, looking at the variety of imple- 

 ments which have been recently introduced into this 

 country, suitable for spraying or washing either 

 orchard tree leafage or that of field crops, there would 

 be no difficulty in experimenting, at least on orchard 

 foliage, as to the effects of cold water in clearing off 

 caterpillar presence. 



The treatment for prevention of surface caterpillars 

 may be shortly described thus : — Turn them up by 

 cultivation where land is known to have been infested ; 

 and where catch-cropping is practised let the field be 

 cleared of all food at least a fortnight before a new 

 crop is put in ; keep up the strength of the crop, but 

 use remedies if you can, — if they will be sure to de- 

 stroy the grubs. 



In a very large number of attacks, it is the worst 

 possible practice to tr}^ to work directly on the grubs ; 

 you must counteract their mischief, rather than try to 

 get (literally) hold of them; but with the large Moth 

 grubs, which are often one, instead of a score or 

 hundreds, to a plant, the case is different. 



For the same reason, birds lid}) us much with some 

 kinds of Moth caterpillars. They can bore down, and 

 •draw out these large grubs, without the broadcast 

 destruction which often follows on their services in 

 searching for Wireworm. 



The crow, raven, jackdaw, rook, and partridge, are 

 all said to be of use in clearing away the caterpillars 

 of tlie Turnip Moth ; and in the case of some of the 

 swarms of small caterpillars which attack forest trees, 

 especially the Small Green Oak-leaf Roller {Tortrix 

 viridana), the flocks of birds which collect when great 

 attack is going forward are our only helpers. 



In the preceding pages I have endeavoured to give 

 some idea of the characteristics of the methods of life 

 of some of the chief divisions, agriculturally considered, 



