MUSTARD BEETLE. 
75 
Beetle to crops of White and Brown Mustard, which are largely grown 
for seed in the district. On some farms the cultivation of these^crops 
has been given up (at least for a time) because they were so infested 
with this plague. The chief damage is done either by the grubs, 
“the Black Jacks,” or by the brood which is in full vigour in July. 
They seem at this season to eat out all the succulent part of the 
plant, and to leave only the woody fibre, and they so completely 
destroy the shell (cosh) of the seed-pod that the seed is shed and falls 
to the ground. 
From a Mustard field they troop off to anj^ neighbouring field 
where plants of the same tribe are to be found. They will completely 
devour a field of Bape if it is in a young stage, and a crop of Kohl 
Rabi, with bulbs as big as an orange, may sometimes be seen with the 
leaves eaten off by these insects, nothing but the rib of the leaf being 
left. At this period they seem to make little use of their wings. I 
have stopped their progress completely by burning damp straw in a 
gateway through which they were passing, but previously they fly 
vigorously. No attempts appear to be made to check the pest, except¬ 
ing the above plan of occasionally burning straw or stubble to arrest 
their progress when moving from one crop to another, or burning the 
straw or haulm after the crop has been reaped, by which means the 
great numbers of beetles which had sheltered in the hollow stems of 
the plant are destroyed. 
Mr. Little mentions that the Brown Mustard crop is not often 
seriously injured by this insect, as it ripens a little too early for the 
young brood, but the White Mustard, which is always a little later, is 
often completely destroyed. The best preventive of the ruin of the 
crop is considered to be sowing as early as is safe to secure good 
germination (and that the young plant shall not suffer from frost), and 
liberal manuring. The vigorous plant can thrive under an attack 
which would destroy a weakly one, and an early ripening diminishes 
the risk. 
It appears from the notes of various observers that the Mustard 
Beetles live through the winter, and shelter themselves in different 
kinds of places, sometimes amongst the roots of grass, often in hollow 
stems of Mustard * or the pipes of reeds, and it appears likely that, 
just in the same way with the Turnip Flea Beetle, to which they are 
* Mr. Little mentions—“ 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.” Looking at the 
fact of the beetles being known to shelter in Mustard straw in the winter, it appears 
well worth while to make out accurately whether they harbour in sufficient quantity 
in the old straw to make the loss on burning this less than what would be caused by 
the broods the wintered Beetles would start in the next spring. 
