44 



FARMERS BULLETIlSr 856. 



of October, or later or earlier, according to season and locality. 

 Figure 48 shows the work of this species on cucumbers. In the 

 worm stage this species causes damage to the roots. This, however, 



is seldom noticed. 

 The beetles are car- 

 riers of cucurbit 

 Av i 1 1 and mosaic 

 disease. 



(' ontrol. — The 

 simplest remedy for 

 garden use is cover- 

 ing young plants 

 with a cheeseclotJi- 

 covered frame made 

 by cutting a barrel 

 hoop in two, so aa 

 to form two semi- 

 circles. These are 

 placed at right an- 

 gles to each other 

 and the lower ends 

 sharpened and in- 

 serted in the ground with the curve uppermost. A cheap mosquito 

 netting covering is readily penetrated by the beetles, and heavy 

 cloth keeps out the sunlight. The lower edges must be held down 

 by stones or other weights. 



Plants may be set out as early as possible and thus avoid the beetle, 

 although there is danger of frosts. 



Another method is to plant more seed than is necessary by plant- 

 ing once each week in one of the squares as represented below : 



Fig. 49. — Tho 12-spott(Hl cucumbcT boeUe (Diahrotica duo- 

 decimpuiiciata) : a. Beetle; b, egj? ; c, larva; d, anal seg- 

 ment of larva ; c, work of larva at base of cornstalk ; 

 f, pupa. All much onlargtd except c, which is reduced. 

 (Riley, except /. i 



1 : 2 

 3 : 4 



The first and second plats are often killed, and sometimes the 

 third, but as long as the insects are poisoned with lead arsenate a 

 good stand is almost sure to be secured. 



Lead arsenate as used for the Colorado potato beetle is the most 

 useful remedy against this species. Bordeaux mixture, added to the 

 lead arsenate, acts as a repellent and prevents injury to the foliage so 

 treated. 



•\vi:i.vK-si 



IKl) CrriMHKR HKKTLK. 



The 12-spotted cucumber beetle (fig. 49) is a little larger than the 

 striped species and eats practically ever^'thing, and when it occurs on 



