148 TURNIP. 
had written to me regarding some method of stopping ravage on the 
Mangolds, which the Surface Grubs were then ‘ eating off very fast.”’ 
In reply, on July 28rd, he mentioned that he was trying the salt 
and nitrate of soda, and thought it should do good. 
On August 12th he wrote further :—* You will no doubt be glad 
to hear that the treatment you recommended for the grub which was 
attacking my Mangold has been completely successful in arresting the 
pest, and I am very grateful to you for it.” And a little later, on 
August 20th, with the remark that he was anxious to make a few more 
observations about the Mangolds, he favoured me with a few lines of 
details of method of application :— 
“T simply kept the hoes going freely in these Mangolds, both 
between the plants and between the rows, and I then hand-sowed 
down them some salt and nitrate of soda mixed, at the rate of about 
three cwt. per acre.””—(H. P.) 
The success of the experiment in this carefully observed instance 
seems to me to make it well worth while to try it again when the 
Surface Caterpillars begin to male their regular yearly reappearance. 
oN: 
Turnip and Cabbage Gnat Midge. Cecidomyia brassice, Winnertz. 
On October 12th I was favoured by Mr. W. Sim, of Gourdas, 
Fyvie, Aberdeenshire, with observations regarding a small maggot 
which he was finding very injurious to Turnip seed in the pod, and 
of which he enclosed me specimens. From these, and also from 
specimens of the Gnat Midge which he had reared from some of the 
maggots, it appeared to me the infestation was of the minute gnat 
known as the Turnip and Cabbage Gnat Midge, of which the maggots 
are to be found in great numbers sucking the seeds, and causing 
deformed growth of the seed-pods, of Turnip, Cabbage, Rape, and 
others of the Cabbage kind. 
Mr. Sim’s first communication was as follows :— 
“Injury done to the Turnip seed crop.—When the seed-pods were 
nearly matured they suddenly turned yellow, and when handled they 
would open up in the same manner as if ripe and dry; but, instead of 
seed, a number of small white maggots would tumble out. The 
infested seed-pods contained from two or three to thirty, but generally 
from twelve to twenty, in each. The depredators eat the lining of the 
seed-pod as well as the young seed, hence the cause of it opening, I 
