The Pygmy Mangold Beetle. 
231 
where they have been at work showing blackened spots. 
Frequently they bite the plant almost through near the ground 
surface. The crop may thus be entirely destroyed, and the 
farmer, visiting it by day, sees nothing to account for the 
disaster. If he pulls some of the plants up the two or three 
miniite beetles which may be clinging to the roots may very 
well escape his notice, and if he sends them to an expert for 
examination the very active insects will almost certainly have 
escaped before the plants reach their destination. If, however, 
he knows what to look for, and lifts some of the damaged 
seedlings with their accompanying soil, the beetles soon betray 
themselves by crawling about. If the crop be visited at night 
multitudes of the insects will be found above ground. Thus, 
if it is once recognised as a likely cause of mangold failure, 
there is no difficulty in determining its presence in any given 
case. The trouble in the past has been that it was so little 
known as not to suggest itself as the cause of injury, and so 
small and elusive as to escape observation when the crop 
was examined, or when injured seedlings were sent for expert 
examination. 
Clearly this pest deserves more attention than it has yet 
received, for nothing seems to be definitely known of its 
life-history. We require in the first place to ascertain the 
frequency of its occurrence, and the circumstances — of weather 
and of ci’op rotation — under which it generally appears. It is 
especially necessary to find out where and how it lives in the 
intervals between mangold attacks. 
In cases of a pest such as this, which is better known in 
other countries than in England, we are naturally anxious to 
benefit by the experience of our neighbours, but with regard 
to the pygmy mangold beetle they give us little assistance. 
The information derivable from foreign entomologists may be 
summed up as follows : — 
1. The circumstances which seem to favour the attack are a light gravelly 
soil and prolonged dry weather. (The latter circumstance was certainly 
wanting in the Essex attack last May.) 
2. The beetles are sometimes found infesting dry dung, and may therefore 
be sometimes conveyed to the crop in farmyard manure. It seems likely, 
therefore, that the substitution, as far as possible, of chemical manures would 
be beneficial. 
3. Where the beetle is known to occur, extra thick seeding and stimulating 
manures are recommended. 
I. Kirchner recommends impregnating the seed with five parts sulphate of 
magnesia and one part carbolic acid in one hundred parts water for twenty 
minutes. [ Das impregnienen der Kiibenknaiil mit 6 teil schwefelsaurer Magnesia 
1 teil Karbolsaiire auf 100 teile Wasser (20 minuten lang).] 
5. The beetle is most injurious where sugar beet is grown year after year, 
so that the ground does not get the benefit of a proper rotation. The difficulty 
is partly met by sowing the beet in patches, and planting out. The patches 
