123 



Ichneumon, Scamhus pedalis, Cress., as well as by Theronia melano- 

 cephala, Brull., and Amhlyieles malacus, Say, which fact prevents their 

 attaining the rank of important shade tree pests, 



Fletcher (T. B.). Report of the Imperial 'EnXomoXogXst.— Scientific 

 Reports Agric. Research Institute, Pusa, for 1916-17; Calcutta, 

 1917, pp. 71-90. [Received 14th January 1918.] 



Experimental work on insect pests was continued, and parasites of 

 the cotton boll worm, Earias spp., were bred and despatched to the 

 Punjab, being identified as belonging to the genus Microbracon. The 

 life-history of Nephotettix bipunctatus (rice leaf-hopper) was worked 

 out. Investigations on the different species of borers attacking 

 sugar-cane, maize, Sorghum vulgare (juar) and rice have resulted in the 

 following determinations : — Chilo simplex, found in maize, sorghum 

 and rice ; Diatraea suppressalis {auricilia), chiefly in sugar-cane, a few 

 examples being found in sorghum, but not in maize ; Diatraea venosata 

 {striatalis), found in sugar-cane and a thick variety of sorghum, and 

 none in maize ; an unidentified species of Diatraea found in sugar-cane 

 only. All the above have hitherto been recorded as Chilo simplex. 

 In addition there are : — Papua depressella, the most injurious of all 

 borers to young sugar-canes, its activities, however, decreasing with 

 the growth of the cane ; Scirpophaga xanthogastrella {auriflua), one of 

 the first borers to attack cane ; Sesamia inferens, known to occur in 

 maize, sorghum, sugar-cane, rice and several other members of the 

 Oraminaceae. 



Observations made month by month of the damage due to insects 

 and red rot on experimental plots of thick, medium and thin canes 

 respectively has led to the conclusion that red rot causes a high 

 percentage of damage, that a thick variety (Purple Mauritius) is more 

 liable to attack than other varieties, the amount of damage due to 

 insects in June being greater than in any of the other plots, even 

 though all affected plants had been cut out in April and again in May ; 

 and that Scirpophaga will prove to be the only insect amenable to the 

 treatment by cutting out affected shoots. 



Other insects observed for the first time feeding underground among 

 sugar-cane roots were the larvae of the Dynastids, Alissonotum piceum 

 and A. simile, and of the weevil, MyUocerusblandus. An undetermined 

 Melolonthid grub, probably Anomala sp., has been observed killing 

 young shoots by gnawing into the stems from the side, and larvae of 

 MyUocerus discolor have been found commonly among the roots. 

 Further observations have confirmed the view that termites damage 

 sugar-cane shoots and setts only in certain kinds of soil. These 

 may be protected by dipping in a solution of 1 lb. lead arsenate in 

 2 gals, water, while a strength of 1 lb. in 1 gal. had no harmful effects 

 on germination, and weaker solutions up to 1 lb. in 4 gals, were also 

 •effective. 



In the insectary more than 200 different lots of insects were reared, 

 most of them for the first time. Among those that may rank as serious 

 pests are Cerambycid borers of Sann hemp and Phaseolus aconitifoUus, 

 and Anobium sp, in stored cumin seeds and aniseed. 



Investigations were made into the life-histories and habits of the 

 pea-stem fly, which was found to damage only plants growing alone 



(C452) c2 



