COTTON LEAF HOPPEli. 109 



wiien tlie plant is shaken. It is distinct from the cotton aphis since it is 

 veiy active, both leaping- and flying- ; when it is plentiful, great numbers 

 leap from the cotton plants when they are shaken or disturbed, and 

 this is the simplest way in which to detect the pest. The insect belongs 

 to the family Jassida, leaf hoppers, of which great num- 

 bers live in g-rass or almost any veg-etation ; they are so 

 small as to escape notice. The eg-gs are laid in the tissues 

 of the plant, and the young- that hatch are similar to the 

 full grown insect but wingless and smaller. The food 

 consists of the sap of the leaves, which is extracted by 

 means of the slender sucking apparatus which forms the 

 mouth. The species attacking cotton may be found at 

 all times of the year both in grass and in cotton. Healthy 

 vigorous cotton is less attacked than weak unhealthy cotton ; c- -lo*- 



° . , tlG. 127. 



fewer insects are to be found on vigorous cotton plants coUon Leaf 

 and the leaf hoppers prefer to live on unhealthy plants. As Sopper. 



. , , PIT ii. • {Magnified.) 



a pest, the insect has been found only on cotton growing 

 under unsuitable conditions. In 190i, there were plots of healthy cotton 

 and of cotton that had suffered from the drought, growing side by side in 

 one of the Government experimental farms. Few insects could be found 

 in the former, whilst the latter contained enormous numbers. Tliis was 

 observed also in Behar, where cotton was being tried and suffered heavily 

 from the excess of moisture. The absolutely backward cotton was 

 infested, the vigorous cotton was practically free. As a pest then it will 

 be found attacking weak cotton; the result of the attack is that the 

 leaves curl, become discoloured^ wither and fall off. 



The pest is apt to kill cotton that is struggHng against bad conditions. 

 It appears to attack the larger leaved tree cottons and American varieties 

 more than the smaller leaved Broach-Deshi and Goghari cottons, but will 

 attack every variety if the plants are in bad condition. Evidently this 

 insect cannot rank as a general pest since it will not attack healthy 

 cotton. It is a serious pest in the experimental farnis* where introduced 

 varieties are being acchmatised ; it has also been a pest to many varieties 

 of the American and Egyptian cotton grown in Behar during the wet 

 months. It has been successfully checked by spraying with crude oil 

 emvdsion, at the rate of 1 in 50 of water. An acre of badly infested 

 Goghari cotton treated with a Success Knapsack machine requires 100 

 gallons of wash, costing Rs. •'3-8, and one day for application. A large 

 amount of wash must be used since it is desired to spray the insects as 

 they come out of the plants in a cloud, and not to spray the plant alone. 

 This is a simple and effective remedy ; no other appears Hkely to be so 



