141 



hill in a field from which the cane had been cut two months previously, fourteen 

 adults, three pupa, and seven larvae were taken. 



Little or nothing is known of the length of larval life of this particular 

 species, but, based upon a knowledge of related insects, the assertion can safely 

 be made that deep and repeated plowing and other vigorous cultural methods 

 accompanied by allowing the land to rest for one or two years and the planting 

 of other crops would be the only means of successfully combating this insect. 



THE CANE TIP BOEEB. 

 (f Scirpophaga intacta Sn.) \_Pyralid(E.] 



The young cane, three to four months old, over certain large areas was badly 

 attacked by a tip borer resembling, in the appearance of the larva and the 

 character of its work, the species described by Van Derventer ' as damaging sugar 



cane in Java. . u^-„ 



It is claimed by the farmers in Negros that this insect, rather than being 

 injurious, serves as a pruning agent, thereby reducing the excessive number of 

 ratoons springing from a single hill, and thus saving them the labor of cuttmg 

 out the excess of plants. 



It would seem that this is a very poor means of accomplishing such a resu t 

 especially as cases have been seen where all the plants in many rows 8 to 10 

 meters long were aflfected. Moreover, the energy expended by the plant m 

 sending up these excessive ratoons, later to be destroyed by insects, might have 

 been utilized in the production of fewer and more robust ratoons, less subject to 



insect attacks. , ,, . • <. u^„ 



As there wa's no time to investigate the whole life history of this insect when 

 I visited these plantations, it is impossible to state the best season for cutting 

 and destroying plants known to be attacked. It is very easy to- distinguish them 

 in a given field, as their top and center leaves are invariably dead and of a pale 

 yellow hue. 



THE WHITE LEAF LOUSE. 

 (Oregma lanigera Zehnt.) [Aphidce.'i 



^niis insect was found in great abundance on a single hacienda near the town 

 of Cabancalan, one field of about four months' old cane being very badly infested. 

 There is no doubt but that the serious degree of infestation was due to the 

 excessive crowding of the plants and the absolute lack of any cultivation since 

 the old crop had been cut off. . , , . ^ 



It was very evident that the only remedy for this condition of things was to 

 bum off the infested cane and either replant after proper preparation of the 

 ground or trust to a resprouting from the old stands. Both of these methods 

 were suggested to the owner, but he seemed quite unwilling to take the responsi- 

 bility, as the cane was bing worked on shares with another man. 



The size of the field and the dense growth of the cane would have precluded 

 anv attempt at spraying such as is recommended by Van Deventer,* even if the 

 farmers in this part of the world were familiar with the use of sprays and spraying 



apparatus. 



""^iandb^tenl]e^^van"d7s^ik^i^a^ulture en de Rietsuiker-fabricage 

 of Java. Tweede Deel, de Dierlijke Vijanden van het Suikerriet (1906), 114. 



* Loc. cit. 187 and 196. 



