i'KOCEEDlXGS OF THE THIRD ENTOMOLOGICAL MEETING 611 



from Ramnagar in the Murshidabad district to compare them with those 

 found at Pusa. The two sets of specimens were sent last year for identi- 

 fication and both were declared to be the same species, Phenacoccus 

 hirsutus, Gr. The disease is known as Tukra, Kokra, Thopna and Topor 

 in Bengal (vide letter from Mr. A. C. Ghosh, Superintendent of Sericul- 

 ture, Bengal, dated the 16th December 1918). The" local names are 

 symboHc of the malformation caused to the leaves and shoots by the 

 mealy-bugs. The disease has hitherto been noticed by me at Pusa and 

 the silk-growing districts of Bengal, Murshidabad, Malda and Bankura. 

 But it is possible that it is more or less present in some of the other 

 mulberry-silk-producing districts of the country. The disease is so promi- 

 nent and characteristic, that once seen it cannot soon be forgotten. The 

 shoots of the affected plants first turn coppery-green, then pale -yellow 

 and ultimately become so hard and compact that it is not possible to 

 open them without breaking away the crisp leaves. With the appearance 

 of the malformed shoots the lower lateral leaves become seared and fall 

 off prematurely. In cases of severe attack, there may be seen nothing 

 but the bare stems of plants standing in the field. The apical leaves, 

 if they do not turn pale-yellow, become so crisp and devoid of nutrient 

 constituents, that they become unfit to be served to Bomhyx mori cater- 

 pillars. In some years the disease is very widespread and considerable 

 damage is done to the leaf- crop, and in such years there is heavy loss to 

 the cultivators who take to leaf cultivation and supply. The disease 

 seems to have obtained a permanent footing in mulberry-silk -producing 

 districts in Bengal for the reason that the remedies hitherto adopted for 

 eradicating the pest are to collect the affected shoots and to throw 

 them outside the infested fields, in a ditch or a pool of water close by. 

 The nymphs as well as the mature females crawl over from these and 

 again infest the succeeding crop. In this way the pest runs on its course 

 uninterruptedly. Besides this, the nymphs as well as the gravid females 

 are blo\^m away by the wind with the fallen leaves and these have been 

 found to lie buried in a pit close by the infested fields. As soon as the 

 winter is over, the eggs hatch and the nymphs walk over long distances, 

 ultimately reaching their favourite foodplants, the cotton or the mulberry. 

 The eggs and nymphs have also been observed to be transported to new 

 places by means of the nymphs and females of Pseudococcus virgatus, 

 Ckll., as well as other insects. During the winter the matured females 

 move down and establish themselves in leaf-scars, under bark and notches 

 on the stem. There they remain quietly ensconced until the winter 

 is over, when they again move up the plant and establish themselves, 

 preferably on the shoots, thereby producing the characteristic malforma- 

 tion known as Tukra or Kokra of Mulberry. 



