220 
Methods of Preventing and Checking 
spoils the gooseberry and currant crops in plantations and 
gardens. Caterpillars of a moth known as A nisopieryx jEsc ularia 
have lately taken to eat the foliage of filbert and cob-nut trees 
in Kent, and cause much loss to gooseberry growers, by eating 
the leaves and young fruit.' The mustard beetle (Phcpdon hetnlce) 
has much troubled the mustard-seed growers in Cambridgeshire 
and Lincolnshire since 1884. 
There are many other insects more or less vexatious to 
British cultivators that might be enumerated. Enough has, 
however, been adduced to show that crops of all kinds are ex- 
posed to the most grave dangers from this cause, against which 
it is most essential that instant and constant watchfulness should 
be observed. 
The same remarks apply to fungoid disorders, even more 
dangerous and insidious, whose infection can be transmitted by 
the breezes from field to field, even from country to country, by 
means of spores, or seeds, that cannot be distinguished without 
a microscope. Their infection may also be conveyed in plants, 
seeds, and tubers from one end of the world to the other. 
Glancing rapidly at the chief crop-destroying fungi, 
the potato fungus (Phutophthora vnfestmis), immeasurably the 
most formidable, must naturally be first mentioned. The 
terrible consequences of its ravages in Ireland are historical. 
Until lately no rational or satisfactory remedy was propounded 
for it. It is now believed that sulphate of copper is a valuable 
remedy for this disease, from experiments that have been made 
in the past three years in France, Belgium, and the United 
States. These experiments will be described later on in dealing 
with various substances that have been found useful against 
noxious insects and fungi, together with the machinesi for 
applying them. 
The hop mildew (Podosphcera castagnei) ravaged the English 
gardens unchecked until about twenty-five years ago, when the 
planters, hearing reports concerning the beneficial use of 
powdered sulphur against the vine mildew in France, tried this 
remedy upon the hop plants. Though its action is very un- 
certain, depending in a great degree upon the weather, there 
has been a large diminution in the injuries caused by the 
fungus since the employment of sulphur. 
Market gardeners have found the onion mildew (Peronospora 
Scldeidenianti) most troublesome latterly, affecting both the 
onions planted for seed as well as those sown for pulling for 
' Some gooseberries were sent me from Cambridge lately which had been 
half eaten by these caterpillars. 
