I'ltOCEEDI.NGS OF THE 'JH7KD EiVTOlIOLOGICAL MEETIXO 395 



Dasyses rugosellus (C. S. 1873). 



Plate 67. 



Food — Usually decaying vegetable matter. 



Caterpillars of this motli were observed to feed gregariously by boring 

 inside sugarcane stems wliicli had been affected by fungal diseases 

 following the attack of borers such as Scirpophaga and Diatrcea. They 

 did not infest healthy canes. They exuded a profuse amount of silk 

 with w-hich the pellets of excreta were webbed up into tube-like galleries. 



The caterpillars were observed to hibernate from about October to 

 February. Pupation took place in oval silken cocoons covered over 

 with pellets of excreta. Moths emerged in March. 



The damage to sugarcane caused by borers. 



Let us commence with the planting of the setts in the ground. The 

 setts are Uable to be eaten by termites. A short account of what is 

 being done to prevent this damage has been given when dealing with 

 these insects. When the new shoots appear they are liable to be attacked 

 by Termites, Mole-crickets, Melolonthid grubs and other external agents, 

 as well as by all the internal borers mentioned under this crop. Of the 

 internal borers, however, usually only Scirpophaga spp. and Diatrcea 

 auricilia are common at this stage at Pusa, the others occurring in 

 small numbers. The fungal diseases also may appear at this time. 

 The first external symptom of attack by all these destructive agents is 

 " dead heart." The infested shoots are either killed and become entirely 

 dry or continue to be green for some time with their heart-shoot dead 

 and dry. The effect however, is the same in all cases, m^., their further 

 growth is stopped. Except when affected by fungal diseases, all such 

 shoots throw out new shoots from the base, giving rise to the tillering 

 effect so commonly observed. Many of the new shoots or tillers also 

 are attacked in their turn. This struggle between the shoots and their 

 enemies goes on and only those of the shoots which escape being attacked 

 continue to grow. Those which have grown somewhat and formed 

 stems (canes) become immune against some of the enemies but their 

 growth may be stopped at a later stage, as they remain Hable throughout 

 their Ufe to be bored at the top by Scirptophaga spp., in the stem by 

 the species of Diatrcea, Sesamia and Chilo, and at the roots by Termites 

 and Emmalocera. E. depressella itself cannot kill a grown-up cane but 

 the fungal diseases, to which its tunnel affords access, do the work for 

 it. Termites may kill a grown-up plant and, even when they merely 



