Mustard Beetles. 
281 
old broken-up land. An instance of this was given in a crop 
to a part of which none was used, owing to the application of a 
heavy dressing of farmyard-manure. 
" This was not half tlie value of the rest of the field. . . . Proctor and 
Ryland's special mustard manure is very serviceable, the object heimj to 
promote a healthy and rapid growth out of the way of the insects." 
Nitrate of soda is stated to have been used without good 
results, and gas-lime also is mentioned as not found to be O'f 
much use. 
Measures fok Destroying the Beetles or their Grubs. 
6. Is there any kind of treatment found useful in getting rid 
of the grubs, such as dressing with lime or other applications 
when the dew is on ? Or are any measures of service when the 
grubs go down into the soil for their change, such as hand- or 
horse-hoeing which would throw the chrysalids out, or lay them 
open to such birds as may eat them ? Information would be 
particularly desirable as to any methods of destroying the 
beetles on the plants (if any such are known), or of checking 
their progress when advancing in bodies. Notes as to checking 
progress by fire, or by making a trench in front of the advance 
and killing the beetles in it, or by any other means, would be 
very acceptable. 
Quick lime, dry lime, soot, sulphur, and salt are mentioned 
as having been tried without any effect in stopping ravages. 
Likewise Jeyes' Fluid, Condy's Fluid, and rock oil have been 
sprinkled without any good results. A note is given of carbolic 
acid, used strong enough to kill the plants, only killing about 
10 per cent, of the beetles. 
Ploughing in a ruined crop at once has been found of use — 
in autumn to prevent the migration of the beetles on it to other 
neighbouring crops, and in spring to destroy the beetles, and to 
bury the plants with the beetle-eggs on the remains of the 
leaves, as these eggs would otherwise start a new attack. 
Burning the mustard straw and chaff was stated to be desirable 
where the insects are numerous. 
Use of burning Straw or Stubble and of Tar to check advance 
of Beetles. — Notes are given from several localities of burning 
straw (especially damp straw) in front of the line of march of the 
beetles when they are moving in large bodies as being of use in 
checking advance, and thus saving the crop to which they are 
migrating, the fires being lighted to windward so as to drive 
the smoke on to the beetles. Two loads of short damp straw 
