36 



AN INSECT PEST OF THE SUGAR CANE. 



EEPOET TO THE MBECTOE OF THE AGBONOflVtlC STATION 

 BY THE PATHOLOGIST. 



In accordance with, the onder dated June 28 from the Direc- 

 tor of Agriculture to study the disease of sugar cane in the 

 vicinity of Jagiieyal, I have to report as follows : 



There are many spots of land in the colonia of Sr. Francisco 

 Bravo in which the cane is either dying or dead. In some cases 

 there are stalks of cane three or four feet high that have grown 

 well for a time as shown by several long joints of cane, and then 

 have suffered some injury so that the upper joints are Tery short 

 and the tops are dying. In all cases these upper short joints are 

 thickly covered with mealy-bugs (Psevdococcus sacchwri) in 

 sufficient numbers to account for the damage. 



All of the stunted canes, whether plant canes or ratoon 

 canes, show abundance of mealy-bug at the base of the stalks, 

 and when the stool is removed from the .ground it is possible to 

 see the roots literally covered with mealy-bugs. 



In many places the poor cane has been burnt off, the fields 

 plowed, and new cane planted. Usually cane replanted on these 

 infected areas fails to germinate, or if it does germinate the 

 shoots are weak and do not produce good cane. Examination of 

 rtiany seed that had been in the soil from one week to three weeks 

 showed the buds covered with mealy-bugs in number sufficient 

 to account for the weakening and death of the shoots. 



The mealy-bug feeds directly upon living cane, either the 

 roots or the stalk, and obtains its nouri^himeht by sucking out the 

 juice of the plant. A few insects do not cause a great deal of 

 injury but large numbers as are present in the Ticinity of Cen- 

 tral Jagueyal cause serious injury and death to the plant. 



The probability of other factors contributiug to this trouble 

 were considered. Termites were found in abundance in many 

 places among the roots and in the stubble of the cane, 'but only 

 in dead parts. A few wfhite grubs were found after digging up 

 the cepas but there was no visible evidence of injury to the 

 roots due to these grubs. No fungi were present in any quantity 

 to render them suspected of causing injury to healthy plants. 

 Soil conditions were equally as good in the infected areas as in 

 the non-infected. i'Hie only conclusions, therefore, that I have 

 reached is that the mealy-hugs alone are responsible for this 

 trouble. 



The extent of the infested areas was not definitely ascertain- 



