Reports to the Board of Agriculture. 139 

 Beetles {Pterostichm madidus) damaging Mangold. 



The beetles daiiiatfiiig manoolds seut by a correspondent were one 

 of the ground beetles or Carahidse, called Pferostichvs madidus, in 

 some works Stempva inadidiis. It is well known as a mangold 

 pest. 



The ground beetles were at one time thought to be only carnivorous, 

 and, therefore, beneficial. Although the majority are carnivorous we 

 now know certain species are very destructive. Three at least, 

 besides the one mentioned here, do a great deal of harm to straw- 

 berries. Steropus madidus, besides attacking mangold and straw- 

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



Miss Ormerod records this species as damaging mangolds as 

 follows : " Sieroiyus beetles were forwarded, which liad been caught 

 also 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. The beetles did not eat the leaves 

 and the damage was noticed as being done in the very early morning, 

 or, in fact, almost in the night." 



They usually attack plants just under the ground or level with it 

 generally where the root begins. The whole root may be eaten right 

 away or may be only partly damaged, as the one sent. When pieces 

 only are eaten out of the root the plant never properly develops ; 

 deformed and stunted wurzel result. 



The leaves never seem to be harmed. Like most CaralldcV, this 

 pest works almost entirely at night and hides away during the day. 

 One favourite hiding-place is under stones. Several attacks have 

 been noticed in fields where flints are abundant. Curtis records this 

 beetle as attacking and feeding upon Wireworm. 



As far as is known, the female lays her eggs either in tlie earth 

 cir under stones. The larvfe hatch from the eggs in eight days and 

 appear to be solely carnivorous. They are dark brown with large head 

 and jaws and six jointed-legs in front ; when mature they are about 

 two-thirds of an inch long ; the end of the body has two long bristly 

 processes. When mature they pupate in tlie ground and remain as 

 pupa; during the winter months. The beetle is common generally 

 in Great Britain, and also occurs in Germany, Belgium, France and 

 Switzerland. 



Prevention and Eemedies. 



After an attack of this pest, land should be deeply ploughed and 

 wurzel should not be grown in neighbouring fields when it is possible. to 



