1912.] 



Mustard Beetles. 



1019 



ground, and pass into the soil for pupation; in a fortnight 

 the new adults may come above ground. Both young and! 

 old plants are attacked. 



Treatment. 



1. The beetles may be collected by shaking them off the 

 plants into vessels containing paraffin, or into receptacles 

 coated with tar. The most satisfactory method for such 

 trapping would be the use of a machine that could be pushed 

 between the rows ; the machine would be provided with strips 

 of canvas and a catching apparatus in the form of troughs or 

 scoops situated low down within five or six inches of the 

 ground. The canvas strips would be so arranged as to hit 

 against the plants as the machine was pushed between the 

 rows, and thus cause the beetles to fall into the traps below. 



Miss Ormerod wrote favourably of such a machine in her 

 Report, 1894, while in 191 1 such a machine, in process of 

 being perfected, was exhibited at the Lancashire Agricul- 

 tural Society's Show. Trapping the beetles before they 

 had laid their eggs would be especially advantageous. 



2. Where great numbers of eggs have been laid on young 

 plants a few inches in height, the wisest measure would be to 

 plough in the crop at once. 



3. Against the grubs a useful spray would be arsenate of 

 lead, care being taken that the spray reached the under-sides 

 of the leaves. The arsenate of lead would be likely to poison 

 any beetles that ate leaves sprayed with it. 



4. Where, later in the year, the beetles are noticed to be 

 migrating to other fields, a shallow trench should be dug 

 across the path of the migrating swarm. If the trench be 

 kept tarred many beetles will be caught. 



5,, After a bad attack by Phaedon betulae, the straw, where 

 it has been left on the field, might, after lying for some 

 time, be burnt in order to destroy sheltering beetles. 



The Turnip, Mustard, and Cabbage Flower Beetle 

 (Meligethes aeneus, Fab.). 



This tiny beetle, belonging to a different family from 

 Phaedon, is an enemy to the seed crop of various Cruciferas. 

 It injures the flowers, and so reduces the amount of seed. 

 Badly infested flowers shrivel. It is often harmful on mus- 

 tard. It may be alone, or it may be present along with 



4 A 2 



