96 



PESTS OF THE COTTON PLANT. 



Generally the picking of the first bolls is praetieuUy the only method 

 that can at present be advised. When the cotton bolls are formed at one 

 season only and the crop ripens (piickly and iiearly simnltaneonsly, 

 this method is capable of g-eneral application ; in the case of cottons that 

 yield slowly and continuonsly over lono^ periods, it is doubtful if a full 

 crop can ever be obtained or even a reasonable proportion of the crop. 



For such cottons the pest may be regarded as a very serious one. 

 Trap crops of annual cottons may effect something" in the case of valuable 

 tree cottons, if such trap crops are nsed intelligently, but this method 

 also is only in the experimental stage. 



The Cotton Leaf=RolIer.i 



A slender caterpillar of a pale greenish colour with a dark-coloured 

 head, which lives upon the lower side of the leaf of the cotton and bhindi 

 plants, folding the leaf over and eating it ; it is easily recognised and is a 

 very common pest of these plants. As a cotton pest it is of some import- 

 ance, especially in the early life of the plant, and needs to be vigorously 

 checked from the outset if it is not seriously to injure or delay the crop. 



Life Histori/. — The female moth, flying in the dusk or at night, lays 

 her eggs on the lower side of the leaves, one here, one there ; sometimes 

 one on each leaf, often two or more. The eggs are small, round greenish 

 objects, about the same size as the head of a small pin. They hatch in a 

 few days and a tiny slender caterpillar comes out. The young caterpillar 



feeds upon 

 the leaf gnaw- 

 ing the lower 

 side ; it spins 

 threads over 

 and around it- 

 self as a protec- 

 tion and soon 

 sheds its first 

 skin and grows 

 larger. It then 

 continues feed- 

 ing upon the 

 leaf ', as a rule 

 it turns the 

 edge of the leaf 

 over in a fold 



*^^ 



S 



Fig. 108. 



Cotton leaves, rolled hy the Cotton Leaf -Holler, 



(The left hand leaf contains tioo caterpillars.) 



37. Sylepta dero^ata, Fabr. (Pyralidse.) 



