INSTITUTE, PUSA, FOR 1918-19 89 



and it is therefore only necessary to give here a brief 

 summary together with additional facts elicited since the 

 preparation of the paper referred to. 



Our experience, under conditions at Pusa, is that the 

 treatment of borers by means of cutting out of " dead- 

 hearts " is of no avail in sugarcane, especially in the case 

 of the young crop, which is best left to grow undisturbed. 

 Treatment by removal of " dead-hearts " seems distinctly 

 injurious to the young crop by interfering with proper 

 tillering. The borers which occur at Pusa (with the excep- 

 tion of Scirpophaga xanthogastrella which bores in the 

 top-shoots) do comparatively little damage to the grown 

 canes. 



Reckoning all the dipterous maggots as one, since it 

 has not yet been found possible to discriminate the different 

 species of dipterous borers, over thirty different insects 

 have so far been discovered to bore in sugarcane, rice, 

 maize, juar {A . Sorghum), the smaller millets, and the vari- 

 ous wild species of Saccharum. Of these, eleven occur in 

 sugarcane, seven in rice, six in maize and juar, and four 

 in the smaller millets. The borers in the wild species of 

 Saccharum must be looked upon as potential enemies of 

 the cultivated grasses also. 



Up to the present, 'twelve different species have been 

 discriminated amongst those previously lumped together 

 as Chilo simplex (" moth-borer "). A key to the larval and 

 pupal stages of some of these was given in last year's 

 Report and a more complete key has been given in the paper 

 referred to above. It need only be noted here, therefore, 

 that the form referred to in last year's Report as ? Chilo 

 sp. in rice (C. S. 1768) has since been found to be identical 

 with the ? Diatrwa sp. in sugarcane at Dacca (C. S. 1674; 

 t. 7, ff. 1, 2), and that Diatrcea sp. (C. S. 1610), found in 

 sugarcane at Dacca and Pabna, has since been named 

 Argyria tumidico stalls by Sir George Hampson. 



The alternative foodplants of the various species have 

 been given in the paper referred to. A new alternative 

 foodplant, viz., Saccharum fuscum, of Scirpophaga xantho- 



