41 

 SOME INSECTS WHICH ATTACK THE ROOTS OF VEGETABLES. 



By Arthur Gibson, Chief- Assistant Entomologist, Experimental Farm, 



Ottawa. 



The roots of vegetables are liable to attack by the larvae of certain 

 insects, some of which ,when excessively abundant destroy whole fields 

 of crops. The more important of these are the following: 



ROOT MAGGOTS. 



These maggots which attack the roots of such vegetables as cablarages, 

 cauliflowers, turnips, radishes, beans and the bulbs of onions are sim- 

 ilar in appearance, being ^\^hitish in color and about one quarter of an 

 inch in length. The species w^hich attacks, cabbages, cauliflow^ers, radishes 

 and turnips is called the Cabbage Maggot (Pegomya brassicae), and 

 that which destroys the bulbs of onions is the Onion x.xaggot 

 Pegomya ceparum.) There is a third species which works in beans 

 and corn, namely the vSeed-corn Maggot (Pegomya fusciceps.) The 

 adtilt flies of all these species are rather smaller than the common 

 housefly. In spring w^hen cabbages and cauliflowers are set out or when 

 radishes, onions and. beans appear above the ground, the adult flies de- 

 posit small, white, elongated Qgg'^ on the stems of the piants. These 

 hatch in a few^ days and the young maggots burrow down and feed upon 

 the roots. There are several broods in a season and injury may continue 

 from May until Autum.n. The chief injury is done in May and during Juue. 



REMEDIES. For cabbages and cauliflowers the tarred paper disks 

 made frotn tarred building paper, cut into hexagonal form andj placed 

 around the stems at the time of planting will protect the plants against 

 the ravages of these maggots. The disks are quickly cut out by means of 

 a tool made as shown in the accompanying figure. The blades of the tool 

 can be made by any expert blacksraiith from a band of steel bent in the 

 form of a hexagon. The piart making the star shaped cross is made from 

 a separate piece of steel. When the cabbages or cauliflowers are planted 

 out the disk must be placed around the stems as soon as possible. Care 

 must be taken in this regard so that the disks will fit closely and lie flat 

 upon the ground, otherw^ise protection Avill not be complete. The object of 

 these disks, of course, is to prevent the flies from laying their eggs upon 

 the stems. For radishes, onions and garden turnips a carbolic mixture 

 consisting of one pound of hard soap dissolved by l)oiling, in a gallon of 

 w^ater and afterwards adding one pint of crude carbolic acid and the 

 whole boiled for five minutes, is useful. Such a formula will make a 

 stock solution one part of which should be used to fifty parts of water. 

 Fresh pyrethrum insect powder, or white hellebore, two ounces to one 

 gallon of water, are also of value. All of these mixtures can be applied 

 in small gardens by means of a w^atering can, or in larger areas may be 

 sprayed directly up(pn the plants by means of a spraying pump. The first 

 application should be made just as soon as the plants appear above the 



