BLACK APHIS}; COLLIER. 55) 
above, have ceased to be useful, there is no reason against removing. 
them, with a good hope that if the centre is still healthy the plant may: 
be saved. The power of making a fresh start when growth is. well 
pushed forward by stimulating manure is excellently shown by the 
following observation of successful treatment of badly attacked Man- 
golds at Rothamsted in 1890, which I was favoured with by Mr. J. J. 
Willis, by kind permission of Sir John Lawes.* In this instance the 
damage to the leafage was from Leaf Maggot, but the power of recovery 
of the plant would be the same whether outer leaves were destroyed 
by the Leaf Maggot within them, or Aphides sucking their juices, or 
Beet Carrion Beetle clearing off the leafage bodily down to the 
centre. : 
The Rothamsted observation was as follows :—‘‘ Insect injury, 
1890.—A field of Yellow Globe Mangolds of fourteen acres on the 
farm of Sir J. B. Lawes, at Rothamsted, was badly attacked by the 
Mangold-leaf Maggot (Anthomyia beta). The field was manured with 
twenty tons per acre of farmyard dung, applied just previous to sowing 
the seed. The injury commenced in July, and gradually got worse, 
until the leaves of the whole crop had the appearance of being scalded. 
They were of a brown colour, and greatly shrivelled up. : 
‘In the first week of August an application of 2 ewt. of nitrate of 
soda per acre was sown broadcast over the whole field. The injured 
leaves soon died off, and the plants formed new growth. The crop 
was taken up towards the end of October, and gave an average produce 
of almost-eighteen tons of roots to the acre.’”’—(J. J. W.) 
The above is a first-rate example of the well-known power of the 
Mangold to recover itself from effects of attack under favourable cir- 
cumstances, and when the cause of evil has ceased of itself, or been 
removed. Also it shows the prudence of the rule laid down, not to be 
over-hasty. to plough in a much damaged Mangold-crop. 
But whilst we all know the importance of a proper amount of 
strong healthy leafage for formation of good roots, it is an open question 
whether we should not benefit very much in lessening insect infesta- 
tions at a small quantity (if any) of loss to size of roots by removal of 
superfluous leaves. This is independent of cutting off leaves which are 
badly infested, which it is obvious is desirable when they are doing 
little excepting acting as a nursery for pests. 
But if we look back to the early days of Mangold-growing in 
England,t when the gold medal of the Society of Arts, &c., was 
awarded to Leonard Phillips for his successful work in the introduction 
* See my ‘ Report on Injurious Insects for 1890.’—Ep. 
+ See ‘Farmers’ Journal and Agricultural Advertiser’ for April 8th, 1816, of 
which Journal (the precursor of our ‘ Bell’s Weekly Messenger ’) a series was kindly 
placed in my hands for reference. 
