90 SCIENTIFIC REPORTS OF THE AGRICULTURAL RESEARCH 



gastrella has since been discovered; this is in addition to 

 sugarcane, Saccharum spontaneum and S. arundinaceum. 



The search for alternative foodplants has been conti- 

 nued as it has been observed in the case of several borers 

 that the presence or absence of alternative foodplants 

 influences to a great extent the prevalence of these borers 

 in cultivated grasses. It seems possible that, by the use of 

 these alternative wild foodplants, the prevalence of at least 

 some of the borers may be reduced considerably in culti- 

 vated crops, but considerable further investigation along 

 these lines is necessary. 



The complete seasonal life-histories of twenty species 

 of these borers has been traced out and incorporated in 

 the paper referred to. 



With regard to the external agents of damage, some 

 further work has been done to attempt to find out what 

 leads to the prevalence of termites in certain soils. Analyses 

 of infested and non-infested soils have been made by the 

 kindness of the Imperial Agricultural Chemist but further 

 comparisons are required before anything more can be said 

 on this subject. 



In April 1919, three species of Dynastine beetles, viz., 

 Alissonotum impressicolle, A. piceum and Heteronychus 

 sublcevis, caused serious damage to sugarcane on the 

 Kamrup Farm in Assam. Mr. C. C. Ghosh was sent to 

 investigate the outbreak and ascertained that the beetles 

 were breeding in large numbers amongst the roots of the 

 various kinds of wild grasses growing over miles and miles 

 of the waste land in the midst of which the Farm is situa- 

 ted, and apparently they occur there every year without 

 doing noticeable damage to the cane crop. This year, on 

 account of drought, the emergence of the beetles was de- 

 ferred until rain fell in March, when an unusually large 

 number of beetles occurred and attacked the crop, especially 

 those portions of it where the germination had been retarded 

 by the drought. Heteronychus sacchari has been recorded 

 as damaging sugarcane but this is the first record in our 

 experience of such extensive damage by adult beetles. 



