I'EOCEEDINGS OF THE THIRD ENTOMOLOGICAL MEETING 379' 



Emmalocera dep-essella {Polyocha sacchareUa). 



Plate 39. fig. 2 and Plate 40. 



Foodplant — Sugarcane. 



Emmalocera depressella may be described as the specific pest of 

 sugarcane. It has not yet been found in any other plant and it causes 

 the greatest damage of all the internal borers which occur in this crop. 

 As its caterpillars always work near the roots of the plants and mostly 

 occur in the roots of old stools in the latter part of the season, it had 

 hitherto been supposed to be simply a root-borer and hence of minor 

 importance. Closer observation has revealed its real nature. In the 

 neighbourhood of Pusa and probably everywhere the greatest damage 

 to sugarcane from borers occurs when the crop is young and the share 

 of E. depressella is usually greater than the damage by all other borers 

 taken together. It cannot most probably be said that this msect has 

 changed its habit recently. The first external symptom of damage in 

 young plants is the " dead heart " characteristic of all internal borers 

 and superficial observation would place it to the credit of Diatrcea or 

 CMlo or Scirpophaga, whose larvae are usually found in the stems of the 

 shoots affected by these latter insects. It is not only at Pusa that 

 E. depessella has been observed to damage young canes. About three 

 3'ears ago more than fifty young shoots were sent from Etawah and they 

 were all damaged by this insect. Last year (1918) out of 69 borers 

 sent from Sipaya early in May, as many as 48 were E. depressella, 20 

 Diatrcea auricilia and 1 Sesamia. E. depressella has also been reported 

 from Sind and observed at Chinsurah in Bengal. In the Agricultural 

 Journal of India, Vo. Ill, p. 104, Messrs. Lefroy and Mackenzie mention 

 its occurrence in young sugarcane at Hathwa, Saran. 



The modes of feeding of the internal borers which have so far been 

 observed in sugarcane shoots are quite distinct. Scirpophaga cater- 

 pillars bore down from the top forming a single distinct tunnel ending 

 in the characteristic exit hole for the future moth. The base of the- 

 heart leaf does not usually rot and therefore does not give out any 

 ofiensive smell. 



Diatrcea auricilia and Chile simplex caterpillars also bore down 

 from the top, and Sesamia larvae may similarly bore down from the 

 top but more often they enter from the side. In the case of all these 

 the tunnel is filled with a wet mass of frass, the " dead heart " comes off 

 with a pull and there is a very ofiensive smell. Also there are always 

 side-holes in the affected shoots but all of these holes may not extend 

 up to the exterior and therefore may not be noticed unless some of 

 the sheaths are removed. 



