Ground Beetles in Mangolds. 



225 



gramme taken to determine the moisture content. The roots are 

 also at once washed, dried, weighed, and split into four quarters 

 longitudinally. One quarter of each root is then sliced by a 

 suitable machine, and an average sample of one kilogramme 

 taken. 



Potatoes are treated in the same way, but the tubers are 

 allowed to lie a few hours on the ground in order that too much 

 soil may not remain clinging to them. The haulm, however, 

 is not collected, as its weight and examination present little 

 interest, but is removed from the field as soon as possible. 



Clover and grass is weighed green on the field, samples of 

 about fifteen pounds taken from each plot, and treated in the 

 same way as the leaves of the root crop. It is not advisable to 

 let the crop dry on the ground, since loss of leafage and other 

 accidents may lead to untrustworthy results. 



Ground Beetles in Mangolds. 



Specimens of beetles, which were found to be injuring 

 mangolds, were recently forwarded to the Board of Agriculture,, 

 and have been identified as Pterostichus (or Steropus) mandidus. 

 These ground beetles are generally common, and were at one 

 time thought to be carnivorous only, and therefore beneficial. 

 (Curtis records this species as attacking and eating wireworms.) 

 Although the majority are so, it is now known, however, that 

 certain species are very destructive. Three at least besides 

 that mentioned do a great deal of harm to strawberries ; and 

 Pterostichus mandidus, besides attacking mangolds and straw- 

 berries, is also found eating swedes and kohl-rabi. 



Miss Ormerod states that these beetles have been caught early 

 in the morning in the act of eating mangolds. The injury was 

 just at the ground level, sometimes all round what may be 

 termed the shoulders of the root, sometimes only on one side 

 or in patches, the damage extending very little below the 

 ground line, and chiefly above it. The beetles did not eat 



S 



