422 



The Profitable Culture of Vegetables. 



Treatment : The pest may be kept in check by sprinkling the beds, as 

 frequently as is possible without making them over-wet, with brine com- 

 posed of one ounce of salt to one gallon of warm water. 



As a preventive measure remove old beds as soon as they are unproduc- 

 tive. Before making fresh beds spray the floor, walls, and roof of the 

 house with paraffin emulsion or a 5% solution of carbolic acid. If the 

 house is quite empty burn sulphur inside and close up tightly. Leave the 

 house immediately the sulphur is ignited, as the fumes are fatal to both 

 animal and plant life. Leave for twelve hours and ventilate well before 

 entering again. 



ONION FLY (Phorbia cepetorum).The Onion Fly is a little over a 

 quarter of an inch long with a wing-spread of about half an inch, dark grey 

 in colour, with red eyes and black legs. The first deposit of eggs is made 

 about the beginning of May, and there are several generations through the 

 summer. The eggs are white and somewhat oval, and are laid in batches 



of six to eight upon the neck of 

 the plant, justabove the ground. 

 The maggots hatch out in from 

 five to seven days ; they are of 

 a dirty white colour, without 

 legs, with a pointed head and a 

 broad tail, and when full-grown 

 are about one third of an inch 

 long. As soon as they arc 

 hatched they begin to burrow 

 between the sheathing leaves 

 and work their way into the 

 young bulbs. The first indica- 

 tions of infestation are shown 

 by the plants flagging and the 

 leaves becoming yellow. When 

 plants presenting this appear- 

 ance are seen they should be 

 examined, when in all probability it will be found that the maggots are at 

 work. 

 Treatment: Similar to that recommended for Carrot Fly, which sec. 



PEA AND BEAN THRIPS (Thrips pisivora). There are many species 

 of thrips, some being serious pests under glass and others attacking plants 

 in the open. Occasionally considerable damage is done to peas and beans 

 by thrips popularly known as the " Black Fly " or " Thunder Fly." They 

 are tiny insects, about one-twelfth of an inch in length, blackish brown in 

 colour, with a lighter-coloured head. The adult insects have four narrow 

 wings, fringed with fine hairs, although the males are often wingless ; they 

 have six very short legs and a mouth formed for both biting and suction. 

 The females appear in spring and lay their eggs upon the unopened flowers 

 of the pea and bean plants. The larvse hatch out in eight or ten days ; 



Onion Fly, Pupa, and Maggot, magnified. 



Lines showing natural size. 



Pupa in stored Onion. 



