32 REPORT ON INJURIOUS INSECTS FOR IQO6. 



she laid two. The eggs were carefully concealed, and were not visible 

 from outside without disturbing the soil." 



Given food, the larva quickly grows, becoming full-fed in about 

 twenty-one days. 



When full-fed the larvae make their way into the soil, but they 

 may remain in the plant. The larval skin hardens, and forms a pupa- 

 rium or external covering for the pupa within. The time the insect 

 remains in this stage varies considerably ; indeed, it may be anything 

 from a fortnight to several months : those flies that emerge in a fort- 

 night or so give rise to another brood, and this may be repeated several 

 times, the final pupa of the year remaining in the soil until the follow- 

 ing spring. 



In addition to cabbage, swedes, turnips, and radishes, many other 

 plants are attacked. 



PREVENTIVE AND REMEDIAL MEASURES. 



Farmyard and organic manures generally are said to attract the 

 flies, and should therefore be avoided. 



Where bad attacks have been experienced, cabbages and all cruci- 

 ferous plants should not be grown on the same land for at least two 

 years. 



Professor Slingerland, in 1894, suggested the use of discs or cards 

 of tarred paper, applied around the stalk. The object is to fit the cards 

 close to the stem and the ground, so that the fly cannot get under it. 

 She will then be forced to deposit her eggs on the card or on the soil 

 beyond it. In either case the larva, when hatched, are unable to reach 

 the plant. I am informed that the use of these cards by large growers 

 in the United States has given most successful results, but I have not 

 found any large growers in this country who will entertain such a 

 method. 



Sand saturated with paraffin and scattered around the plants has 

 proved useful on small areas. Half a pint of paraffin to a bucket of 

 dry sand. 



Carbolic acid and lime made into a thin cream and applied in a 

 similar manner has given good results, as also two pounds of glue dis- 

 solved in a gallon of water and mixed with one-half pound of bran 

 (Washburn). 



THE CARNATION FLY. 



Hylemia nigrescens, Rnd. 



The larvae of this fly have been received from many Midland 

 horticulturists and nurserymen. It has proved a most troublesome pest, 

 and one difficult to attack. 



