no 



tfiSTS Of THE COTTOX PLAJ^T. 



successful. AVliere it is necessary to lielp a struggling crop tlirougK a 

 bad season, spraying of this kind will be a necessity. When the plants 

 become stronger, they T^'ill not show the disease, and will not be impaired 

 by it. 



This insect is known from Gujarat, Nagpur, Cawnpore, Lyallpur and 

 Behar at the present time. It will probably be found wherever cotton is 

 grown in India. 



Cotton Aphis. 



Small sucking insects found in abundance on the shoots and leaves 

 of the cotton plant ; they are about one-twentieth of an inch long, 

 coloured in dull yellow or black, and have two short processes projecting 

 from the upper surface of the abdomen. This pest is one of the common 

 plant-lice discussed in a later section and has a similar life history. The 

 colonies found on cotton consist of female insects, which produce living 

 young. There is no metamorphosis ; the young are born alive and are 

 all females. After a few days they in turn commence to produce living 

 young ones. Two kinds of females may be seen, unwinged yellowish 

 ones and winged black ones. The latter fly from plant to plant and 



Fig. 128. 



Winjed female. {3Iagnified ten times.) 



Spread the pest over the field. As a rule the young and the unwinged 

 females move but little, feeding in compact colonies on the underside of 

 the leaves or on the shoots ; they extract the sap frcm the plant, making 

 it weak and sickly. The insect appears in the rains and, if cotton plants 

 are available, remains on them until the weather becomes very dry, often 

 until the end of the cold weather* In cloudy weather the ringed ones fly 

 far over the field and found nelv colonies. Hence it is that after the 



^B. i4j}liis gosst/fii- Glov. (ApLicla:) 



