19 
stem protudes through the stomata of the leaf into the air. Its branches 
bear spores at their ti =e 
5. One method of combating the disease is to make the onion plants 
as strong as possible, so as to withstand the attacks of the parasite. 
Hence the site should be carefully selected, the soil well a good 
manures used, and the land kept clean and free from wee 
6. To prevent the spreading of the disease all affected plants must be 
collected and burned. Whilst doing this care must be taken that the 
collector does not himself ec: the disease by carrying the refuse 
loosely. Rotation of crops, or, when this is impossible, deep trenching, 
would lessen che. ebaki of the disease appearing. 
7. Diseased plants may be treated with a mixture of powdered 
sulphur and freshly burnt quicklime sprinkled by hand or by bellows; 
or they may be washed or sprayed with a weak solution of iron sulphate 
green vitriol). In both cases the fungus is destroyed without injury 
to the onion plant. Further, both these onia reme'lies have the 
additional advantage of being excellent manu 
8. Another fungus, Macrosporium parasiticum sometimes attacks the 
onions after the Peronospora has taken a good hold of the plant and 
weakened it. As this only occurs as “a sequel to the Peronospora, the 
extermination of the latter would involve the disappearance of the 
former. The Macrosporium does not attack the healthy plant. 
9. Only two kinds of insects, the onion thrips and the onion fly were 
met with, and the latter on only one occasion. e s were not 
numerous and appeared to do little harm. ey can easily be removed 
by application af a solution of iron sulphate, such as is recommended 
in Section IV. i 
Should the onion fly ever prove a serious, pest it may be dealt with 
by covering the bulb of the onion with a thin layer of earth. This 
prevents the fly approaching the bulb to lay its eggs. 
(Signed) ARTHUR E. SHIPLEY. 
Christ’s College, 
ambridge, 
August 3, 1887. 

