INSTITUTE, PUSA, FOR 1917-18 9? 



the end of that month, began to decline again in the third 

 week of June and reached its lowest at the end of July. 



Mulberry. The " Tukra " disease of mulberry, result- 

 ing in curling and malformation of the shoots and new 

 leaves, has been known for a long time in Bengal, where it is 

 sometimes bad, and a few affected plants have lately been 

 found at Pusa also. An investigation of the cause of this 

 disease was carried out during the year, and it was found 

 by experiment that the curling and subsequent malforma- 

 tion of the shoots was due to the presence of a mealy-bug 

 (Pseudococcus), and that, although two species of Pseudo- 

 coccus are to be met with on mulberry, it is only one of these 

 (as yet unidentified) which causes tukra. This mealy-bug 

 becomes active at Pusa at the beginning of March and passes 

 through a complete life-cycle in 24 days. The generations, 

 however, overlap one another, and it is not infrequent to find 

 nymphs, gravid females and pupae or adult males on one and 

 the same plant. The mature nymphs as well as the females 

 are parasitized by three species of Chalcididae, one of which 

 keeps down the number of nymphs and females to a large 

 extent. A Cecidomyiad fly ( ? Coccodiplosis sp.) larva has 

 been found to attack the eggs, the fly maggots being found 

 chiefly in the ovisacs of the mealy-bug and having been 

 observed to suck the eggs dry. The larvae of a Coccinellid 

 beetle also attack the nymphs and females of this 

 Pseudococcus. 



As regards treatment of tukra, it was found that the 

 practice of removing the affected shoots and burying or 

 burning them was not effective by itself, as the nymphs hide 

 themselves in the crevices of the unexpanded leaf-buds on 

 the plants, and, as soon as these leaves expand, they in their 

 turn become affected and the disease is continued. Removal 

 of the affected shoots followed by thorough spraying with 

 Fishoil-resin soap will probably prove more effective. 



Fruit Flies. Over five thousand pupae of the Peach 

 Fruitfly were collected at Pusa in May, 1918, and kept under 

 observation to see whether any would lie over until the 



