POLYANTHUSES. 221 
dent that they caufe its leaves to become 
yellow and fpotted, and eventually de- 
ftroy it; they multiply with fuch aftonilh- 
ing rapidity as to take poffeffion of a 
whole colleflion, in a very fhort fpace 
of time, if the neceflary precautions be 
not taken as foon as any plant puts on 
the appearance of infeftion. 
This infefl feldom attacks fuch plants 
as are in a ftate of vigour, or when the 
weather is cold and wet; it generally 
commences its depredations in the early 
part of fummer, and continues them as 
long as the heat and drynefs of the 
weather favour its exiftence: the juices 
alfo of the plants being then more vifcous 
and faccharine, afford it more fuitable 
nourilhment than at any other feafon. 
Such plants as appear infefled Ihould 
be immediately felefled from the reft, 
taken out of the earth, and foaked for 
two 
