THE WESTERN CABBAGE ELEA-BEETLE. 18 



by frequent cultivation and heavy manuring in order to stimulate 

 the growth of the plant and enable it to recuperate from insect attack. 

 The irrigation system should be so installed that it may be kept 

 constantly in working order, that the plants may not suffer at any 

 time for lack of moisture. It should be unnecessary to add that the 

 crops be kept free from other insects and from disease. 



IRRIGATION. 



Irrigation has been suggested as a remedy for the hop flea-beetle 

 in its occurrence on sugar beets and should be of value where irriga- 

 tion is practiced on other crops. Its effectiveness could be increased 

 by brushing the plants, causing the beetles to jump into the water 

 and be carried away or drowned. 



MECHANICAL TRAPS. 



The use of sticky shields and tarred boards, which have proved 

 effective in the control of the hop flea-beetle in hop yards, might be 

 used against this pest when it occurs in its greatest numbers. The 

 conditions, naturally, are different, but there might be some cases 

 where either would prove effective. 



In 1914 Prof. H. M. Lefroy (9) made use of what he calls the Wisley 

 turnip-fly trap against two allied species of -flea-beetles 10 in then- 

 occurrence on turnip with what he describes as amazing results, due 

 apparently solely to the growth the seedlings make when their leaf 

 surface is entirely unharmed. This trap is made of two boards set 

 at a slope on a pair of runners like those of a sledge with a space 

 between. The trap is drawn along the rows so that the plants pass 

 through the space in the middle. In order to disturb the beetles a 

 loop hangs from a crossbar and brushes the plants. The boards are 

 smeared with a sticky substance, which captures the beetles as they 

 fly up. The illustrations furnished of the trap show that it can be 

 easily made and should prove quite successful where radish, turnip, 

 and similar crops are planted in rows, but, of course, would not be of 

 service where the seed is sown broadcast. 



TRAP CROPS. 



The fondness of this, as well as other cabbage flea-beetles, for 

 radish, mustard, and turnip suggests the employment of these as 

 early trap crops to attract the beetles from the later-appearing main 

 crops of cabbage, sugar beet, and others. The beetles may be swept 

 up from these trap crops by means of a bag sweep net of the type 

 used by entomologists to collect beetles and similar insects. This 

 should afford protection for the main crop. 



10 Phyllotreta consobrina Curt., and Ph. undwlata Kutsch. 



