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INJURIOUS INSECTS AND FUNGI. 



[March 1897. 



INJURIOUS INSECTS AND FUNGI. 

 The Carrot Fly (Psila rosce). 



1. Fly, natural size and magnified; 2. Larva, natural size and magnified; 

 3. Pupa, natural size and magnified ; 4. Infested carrot showing rust spots. 



Carrots are frequently much injured by the larvae or maggots 

 of this fly, which bore into and feed upon their roots, living 

 upon them and causing them to become brown or rusty, and 

 finally rotten. In some cases of early attack the growth of the 

 small roots is entirely stopped. Carrots grown by market 

 gardeners and market-garden farmers for " bunching," or pull- 

 ing early, are not often materially injured as the fly does not 

 appear until the middle of May, though the latest of the early 

 pulled roots are sometimes disfigured and their value depreciated 

 because of the rusty spots made by the larvae ; but those that are 

 dug late for storing, either for human or for cattle food, are, how- 

 ever, very frequently seriously damaged and rot in the clamps and 

 stores, and are unsaleable by reason of the rust marks upon them. 

 It has been noticed that the carrot fly is more injurious in dry 

 seasons, when the growth of the roots is not so luxuriant and 

 rapid as when moisture is plentiful and the rain closes the soil, 

 which in some degree may hinder tie fly from laying eggs, as it 

 is said that the female fly goes below the earth for this purpose. 



Carrots badly attacked by this insect have deep cracks in the 

 roots in which the larvae are found. These frequently extend to 

 the centre of the roots and cause them to rot. The tops become 

 brown and wither away, and in the early stages of this attack, 

 when as yet there are only a few larvae in the roots, the foliage 

 changes and betrays their presence. When these indications are 

 noticed it will be generally found upon pulling up the roots 

 that larvae are protruding from the holes in them (Fig. 4). In 

 bad cases of this infestation, decay is frequently hastened by the 



