No. 1.] H. W. Peal— Two pests of the Indigo Plant. 45 



small ; averaging some 2 or 2\ inches in height instead of 

 some 18 inches, the average size at the time, I invariably found 

 to be thickly covered with aphids. I should estimate that on an 

 average 29 to 30 per cent of the crop was in this state. These plants 

 being so miserably stunted are unnoticed, except in open bare spots 

 and no suspicion is aroused as to the extent of the injury The taller 

 and healthier plants were all free or practically free from the pest. 



At Turkawlia, in the Chumparan district, where there was plenty 

 of rain in May, I found no traces of the aphid, itself, but observed 

 on stunted plants the remnants of the cast off skins of the aphids. 

 These occurred on the stunted plants, which had their vitality 

 so much sapped that despite the rain they were unable to recover 

 thoroughly. 



I am unable to recommend the use of kerosene emulsion for 

 several reasons, the most important being that the infested plants 

 are overshadowed by their healthier neighbours ; they would there- 

 fore be but imperfectly sprayed. There would besides be a great 

 wastage of the emulsion owing to the greater part of it being 

 sprayed on the healthier plants. I observed that the aphid was 

 attacked by at least two insects. First, by the larvae of a species of 

 Diptera, probably of a species of Syrphus. I was unable, however, 

 to rear it. These did not appear to be present in any great numbers 

 and appeared to do but little in checking the aphid. 



I also observed the ladybird Chilomenes sexmaculatus Fabr. 

 in fair numbers. They appear to check the aphids to an appreciable 

 extent, but at most are only a partial remedy. I was unable to 

 obtain any hyperparasites on this beetle, but suspect their presence 

 owing to the comparatively few ladybirds as compared with the enor- 

 mous number of aphids. 



Last year the aphid appeared on an experimental plot of indigo 

 in the Museum compound. The aphids were present in laro-e 

 numbers but were completely exterminated in two or three days by 

 the larvae of the ladybird Chilocorns nigritus Fab. I have every 

 hope that this ladybird, which usually feeds in Calcutta on the 

 coccid Chionaspis [Hemichionaspi?) minor, will prove an important 

 factor in reducing the ravages of this destructive aphid. I was 

 unable to find this ladybird in Behar, even though I examined several 

 colonies of Chionaspis minor, to see if this ladybird was to be 

 found in the indigo districts. I am at present experimenting with 

 them and hope in time to be able to send up several colonies of this 

 ladybird to Behar. Due precautions will be taken to avoid any 

 hyperparasites being sent as well. 



