Measures for 
rome sen out 
the te 
14 
Guano is a very good manure neu used in conjunction with others, 
but it should not be relied upon to the exclusion of natural manures. 
Owing to its very variable composition it shold always be purchased on 
analysis, and samples should be analysed from time to time to see that 
what is supplied is up to the sta se, 
It sa] needless to insist upon the necessity of keeping the gro 
clean and free from all weeds, which should, when gathered Taa 
be mi 
ii. When the onion disease has attacked the aca our attention is 
directed to two problems: Firstly, te! to cure the crop; and, secondly, 
how to prevent the disease spreading. I have pestpeitee considering 
what means may be adopted with a view of curing the diseased plants 
until the third part of this section, and at present I propose to consider 
what means may be adopted with a vie ilies preventing Maw spread of 
the disease both as regards space and time. How can e disease be 
prevented from passing from one field to the naphbourse fields, or 
from one season to the next ? 
The means by which the fungus spreads from one See in a field all 
o a ms thence stat: neighbourin plantations are, as we haye seen 
all on which are abstricted from the ends of the 
brieenes of the fun 
me s their vary ‘minute size oer "e fe ena they float easily 
n the and are borne in countless numb wards whichever 
direction ‘the wind sets. Other agents by which. vies are dispersed are 
insects, birds, and even snails and slugs; in short, the spores may fall 
upon anything and be carried into another plantation. 
e spores exist in such countless millions that when the weather is 
favourable, that is, warm and moist, the disease. spreads with such 
rapidity that it is impossible to cope with it. But, on the other hand, 
if after the first appearance of the fungus the weather should change 
area of the affected field, and in case efforts = be made to arrest 
the progress of the disease with some chance of su 
All affected plants must be carefully collected. ad oe ni. Since the 
presence of the fungus on an onion arrests the growth of the plant but 
little is lost by collecting ce Tana parts, that is, the leaves. The 
ma if it is already formed, may still be used. 
eat care should be exercised in collecting the diseased plants, so as 
g the 
The parts collected shoud. be carefully burned. "As w e have seen 
the fungus bears millions of spores capable of reproducing the disease 
at once; and it also at a later stage produces immense numbers of 
resting-spores, which are capable of Sm in the — until the next 
season, and then See on the new crop and so carrying on the 
diseas ay one season to another. So that by bu bce rning the affected 
onions we destroy both kinds of spores and greatly diminish the chance 
of its spreading. 
4 it is impossible to burn the refuse. it should be mixed with 
quicklime and sonar - a considerable depth, but whenever it is 
ene tions also apply when the disease is at its worst, 
Ifa field of of oiio é Tis been completely destroyed by the disease, the 
