COTTON APHIS!. 



Ill 



cloudy weather, aphis becomes more abundant and suddenly appears over 

 large areas. 



Plant-lice excrete a sugary 

 liquid, which, falling on the 



leaves below, dries to a sticky 

 coating. This appearance on 

 the leaves is a sign of the pest 

 and is familiar to cultivators. 



Many insects attack the 

 cotton aphis and are very im- 

 portant checks upon it; these 

 are described in a later section 

 under beneficial insects. These 

 insects should be familiar to all 

 who grow cotton and should not 

 be destroyed in error as injuri- 

 ous insects. 



The treatment for cotton 

 aphis lies in spraying with a 

 contact poison, doing this when 

 the first colonies appear on the 

 cotton and not delaying until 

 with cloudy weather they spread 

 over the whole field. If culti- 

 vators were familiar with aphis 

 and checked it as soon as they 

 first saw it, it would never 

 become so serious a pest. 

 Without this, large areas may in cloudy weather become an*ccted, and 

 though the pest is principally one on farms and experimental cultivation, 

 it is also an important field pest. 



FIG. 129. 



Cotton Aphis, winged female. 

 (Magnified fifteen, times.} 



Minor Pests. 



There are a number of insects which attack cotton casually, doing as 

 a rule no harm but possibly injurious in unusual seasons* The White 

 Weevil a is a small beetle, of a dull white colour, found upon the leaves of 

 all varieties of the cotton plant almost throughout the year* It bites the 

 leaves of the plant, eating in from the edge* It is most conspicuous from 



1 Myllocerus maculosus. l)es L. (Curculionida.';) 



