INSTITUTE, PUSA, FOR 1918-19 91 



Observations have been made on the parasitization of 

 A leurolobus barodensis, an Aleyrodid destructive to sugar- 

 cane. It was found that the percentage of parasitization 

 was highest at the end of November, 1918, when it varied 

 between 80 and 95 per cent. For a few days the maximum 

 was as high as 98 per cent, and thereafter the numbers of 

 host -and parasite rapidly declined. 



A note on " Some Indian Economic Aleyrodidae." com- 

 prising the species destructive to sugarcane, was prepared 

 and read by Mr. C. S. Misra at the Third Entomological 

 Meeting. 



Indigo. Investigations regarding the parasitization 

 of the Indigo Psylla (Arytaina isitis) were continued 

 throughout the year. Three species of Chalcididae were 

 concerned and of these one was very prominent. The para- 

 sitization was found to be highest at the end of May and 

 September; aiter the latter date it declined gradually until 

 the minimum was reached in February. 



Mulberry. The disease known as " Tukra " or 

 " Kokra " referred to in last year's Report, has been defi- 

 nitely ascertained to be caused by a mealy-bug, Phenacoccus 

 hirsutus, Green, which is found on the plants together 

 with Pseudococcus virgatus, Ckll. The nymphs as well as 

 the adult females congregate on the shoots of the stems and 

 cause the malformation which is so often seen in infested 

 mulberry plantations. Not only is the growth of the plants 

 retarded, but the lower lateral leaves become wilted and 

 drop off. The affected apical leaves, if served to mulberry 

 silkworms, cause " flacherie." Ten generations of Phena- 

 coccus hirsutus were reared during the year and its para- 

 sites and predators were also studied, together with its 

 means of dispersal as well as the best method of treatment 

 of affected plots. Besides mulberry, this scale insect has 

 also been found to occur on cotton, guava fruits, grape 

 vines and fruits, and Tecoma grandiflora. Three species 

 of Chalcididse, as well as Spalgis epius, Eublemma 

 quadrilineata and a Cecidomyiad fly, check this scale to a 

 great extent. The presence of this mealy-bug is easily 



