NEW YORK STATE MUSEUM 93 



troubled with this insect, stated that the maggot was more injurious 

 on the Hghter, dryer parts of the field and that it was decidedly- 

 more abundant during the last few years. He was advised to 

 water the infested plants which were not so badly injured as to be 

 beyond recovery with a solution of corrosive sublimate, one part 

 to looo, using about one-half of a cup full for each affected plant 

 and going over the field several days later, to treat others which 

 might show signs of injury. 



A nearby field of radish was also rather badly infested by this 

 root maggot. 



Investigations and studies of Professor Caesar in Ontario the 

 past summer have led him to make the following suggestions for 

 control of maggots. He advises the using of corrosive sublimate, 

 one to 1000, and for cabbage he suggests the first treatment 2 or 3 

 days after transplanting and the second 5 days later. For radish, 

 he would make the first application 3 days after the plants came 

 through the ground and the second 5 days later. He finds that 

 several fine days are necessary to bring the flies out and five such 

 days before eggs are deposited; consequently as a general rule he 

 favors making the first application 10 days after the first warm 

 spell of at least 5 days occurring after April 25th. 



The experimental work of Messrs Treherne and Rhuman showed 

 comparatively little difference between three and four treatments 

 for the control of maggots. They advocate three treatments, the 

 first 3 days after transplanting and two others at lo-day intervals. 

 The results obtained were superior to those secured with tarred 

 paper disks. 



Carrot rust fly (Psila rosae Fabr.). A rather general 

 though not serious infestation by this insect was observed on pars- 

 nips at Nassau, March 27, 1921. This appears to be the first record 

 of the occurrence of the insect in this section of the state, though 

 it was reported from Fulton county in 1901, from Long Island in 

 1916, and caused considerable injury in the vicinity of Rochester 

 at about the same time. It is evidently widely distributed, since 

 it is known to occur in the northern states from Maine to Michigan, 

 and under certain conditions it is a serious enemy of carrots and 

 celery, though it also attacks parsnips, parsley and wild carrots. 

 A detailed account of this species has been given in New York 

 State Museum Bulletin 64, pages 99-103, and a brief note occurs 

 in Museum Bulletin 198, page 'j'^. 



The presence of this insect in carrots and parsnips is most easily 



