MUSTARD BEETLE. 
57 
To get this pest within our power we want special observations 
from growers of Mustard, but there are some points in the life-history 
which certainly might be worked on as a basis of means of prevention. 
Mr. Harrington, in his letter regarding the attack last spring, 
remarked, “ They were first noticed last autumn on Foulness Island, 
and have kept quiet during the winter, but are now causing serious 
alarm.” This keeping quiet during the winter (like the Turnip Flea 
Beetle, which is nearly allied) helps us to keep them in check by not 
allowing them the requisite shelters to spend the winter in and come 
out from. 
The Mustard Beetles hide at the roots of grass, or creep down 
pipes of reeds near ditches, or into hollow Mustard-stems, or shelter in 
Mustard-straw . In regard to this point, Mr. Little mentioned:— 
“ Some years ago nearly all the Mustard-straw was burnt when the crop 
was threshed, which was generally in the autumn ; but now a good deal 
is saved to make rough sheltering walls for cattle, and the cottagers beg 
a few loads and make use of it for covering their sheds or hovels.” 
Where Mustard is largely grown, the above point of the beetle 
sheltering itself in the rubbish of what may be called “ its own crop” 
would be well worth seeing to. If the plan is still ever followed, 
which was in use some years ago, of separating the seed from the 
straw on the field, burning this straw in small heaps on the land 
would get rid of the shelter, and return much of the material otherwise 
carried off the field to the ground ; or, if left at hand in one heap, 
it might act as a trap, and a large amount of pests be destroyed by 
firing it during the winter. 
As the beetles especially frequent Charlock, also are found at the 
roots of grass, and go down pipes or reeds, &c., it would seem that 
they might be expected to infest neglected corn-stubbles, and that a 
crop of Mustard or Coleseed on the ground, or on ground adjacent to 
such localities, would be likely to suffer. 
It is also open to consideration to what extent Mustard Beetles 
may be sown along with the seed. Mr. Caswell, in his notes sent to 
myself from Peterborough, mentioned :—“ We have found the beetles 
alive in sacks of the seed for two years after it has been threshed.” 
It would be very desirable to inspect seed before sowing relatively to 
this point, and, in case there should be any difficulty as to making 
sure of its condition, it would be my duty officially, as well as a 
pleasure personally, to examine any samples forwarded me as to 
amount of insect-presence. 
It was observed in 1878, by Mr. Marshall, that the Mustard 
Beetles “ completely ” avoided Mangolds, even when the crop was 
alternated with Kohl Babi in the same field. This might be turned 
to account in rotation. 
