114 ONIONS. 
drawn by hand) and burnt. If thrown to the manure heap, as men- 
at p. 110, the wormlets will live on, and they, or their descendants, 
will be presently distributed in the manure, and infest anything liable 
to their attacks,—those bred in Onions being observed to have especial 
preference for again choosing Onions for their attacks. 
Resowing on ground which has been infested is obviously to be 
avoided; likewise care should be taken that none of the earth from 
beds where there has been presence of Onion Kelworm-sickness should 
be carried to other parts of the garden. Even a small quantity of this 
infested soil, such as may cling to the workmen’s boots or to gardening 
tools, as forks or spades, or to the wheel of a wheelbarrow, is quite 
enough to start presence of the pests. 
Where trenching can be managed without loss from turning up a 
barren subsoil, this is a good plan, as it buries down the Kelworms 
out of the way. Digging, or even double digging, only destroys some 
amount of them, and scatters the rest harmlessly (to them); but true 
trenching, in which the upper “‘spit’’ (or spade’s depth) is buried 
down, and the next ‘‘spit’’ beneath brought to the surface, is a very 
effectual way of getting rid of this and many other infestations. 
Probably growing Onions in succession to Celery would answer 
well. The thoroughly deep stirring of the soil in forming the trenches, 
and the rich, well-cultivated state of the ground, would respectively be 
very good for getting rid of the Kelworms, and also for encouraging 
the good hearty growth of the Onions, which enables the plants to 
resist attack, if not absolutely overwhelming. On the above principle 
good manuring is recommended. 
The recipe for destroying the HKelworms in the infested seed, 
without injuring the power of germination, is steeping the seed at 
sowing-time for twenty-four hours in a very weak mixture of sulphuric 
acid and water. The acid used should be the ordinary English com- 
mercial acid, not the coarse dark brown kind, and the proportion, as 
hear as may be, one pint of acid to a hundred and fifty quarts of 
water. But great care should be taken both that this dangerous acid 
(popularly known as vitriol or oil of vitriol) should be carefully secured 
in a well-marked bottle, and kept under lock and key, so as to avoid 
all risk of accidents; and also in mixing it, it should be remembered 
that in certain proportions great heat is generated, sufficient to break 
a glass, or, by some of the mixture flying, cause dangerous accidents. 
Adding the small proportion of acid named to the water is quite safe, but 
before adding small quantities of water to the acid (or other uncertain 
methods of action) advice should be taken. 
As yet we do not hear of this attack, which is so destructive in 
some of the Onion-growing districts in Holland, having appeared in 
our own fields, but even on this broad scale the above principles are 
