Root Maggots and" Ho w^ to Treat Them 



Dr. James Fletcher, Dominion Entomologist, Ottawa 



MONG the insects which the 

 market gardener must consider 

 every year, are the root mag- 

 gots that eat the roots of 

 ions, turnips, cabbages and cauliflow- 

 3. The root maggots are enormously 

 undant in some years. In those years 

 is almost impossible to control them, 

 'here is as yet no practical remedy 

 hich will always give us perfect im- 

 unity from attacks of these insects. 

 fhe eggs are laid by small fiies, very 

 uch like a house fly, but not half as 

 rge, close to the ground, on the stem, 

 ^r near the roots of the plants they at- 

 tack. The eggs hatch in two or three 

 days, and at once bore into the stem of 

 the onion, radish, or cabbage; and if 

 they once get inside, you cannot reach 

 them with any remedy. 



The preventive remedy, which has giv- 

 en the best results, is known as the tar- 

 paper disk. This is a piece of ordinary 

 tarred building paper, about three inches 

 square, split from the centre to one side, 

 so that you can put it around the stem 

 of the plant at the time it is planted. The 

 tarred paper disk is pressed close to the 

 ground, and the creosote in the tarred 

 paper, prevents the insects from laying 

 their eggs upon the stem of the cab- 

 bage, consequently, its roots are not at- 

 tacked. With fresh tarred-paper, we 

 can protect a very large proportion of 

 the cabbages in a plot ; but even with 

 that protection in years of great abun- 

 dance, we have seen clusters of eggs laid 

 even on the tarred-paper. Last year 

 there were root maggots at Ottawa, and 

 we did not find a single egg laid on any 

 of the plants where the tarred-paper 

 disks were used. These are made very 

 easily with a punch, and the time requir- 

 ed to put them on is not very consider- 

 able. 



INSECT POWDER OR HELLEBORE 



Another method, which has given us 

 good results at Ottawa, is applied about 

 July ist, when the effects of the mag- 

 gots become apparent. You can gener- 

 erally detect cabbage plants that are at- 

 tacked, by the bluish appearance of the 

 leaves. I do not advise you to treat only 

 those plants which show they are injured 

 but you should treat them all as a regular 

 .method of culture. When doing this 

 draw away the earth from around the 

 stem of the cabbage and see whether 

 or not it is injured. If there is any sign 

 of injury, the maggots may be killed 

 with a decoction made of two ounces of 

 insect powder or two ounces of hellebore 

 in an ordinary pail of water. Mix with 

 hot water first and then fill up with cold 

 water. Draw the earth away from the 



• Part of an oddresH delivered before the Ontario 

 > egeUiblc Urotveni' AtwKx^iation ut liwl convention. 



roots of the cabbage or cauliflower and 

 then take a cupful of the decoction and 

 pour it in. The poison from the insect 

 powder kills any of- the maggots that are 

 lying in the soil around the roots of the 

 cabbage and the moisture of the mixture 

 applied at that time is very beneficial and 

 gives the plant a push forward so that 

 it will, as a rule, outgrow the injury done 

 by the maggot. With us in Ottawa, 

 July ist, is the time to do this, and the 

 results have been very satisfactory. 



CARBOLIC WASH 



With onions, the attack occurs very 

 early in the season and we have found 

 both for onions and radishes, a good 

 remedy in the carbolic wash, known as 

 the Cook wash. This consists of one 

 pound of ordinary soap or one quart of 

 soft soap, dissolved thoroughly in a gal- 

 lon of hot water, and when it is dissolved 

 turn into it half a pound of crude carbolic 

 acid. Boil for five minutes and then you 



to put on any more. This will keep the 

 flies off sufficiently long for yoti to get 

 your crop of early radishes quite clean. 



In the case of onions you must watch 

 them longer. If they are in light, sandy 

 soil, I have found a good remedy is to 

 take a broom as soon as the bulbs begin 

 to form and walk along the rows of on- 

 ions and brush away the sand from the 

 tops of the bulbs. The broom will take 

 the sand away from nearly three-quarters 

 the way down the onions and unless the 

 sand is well up to the top the maggots 

 will not work there. In heavy soil, this 

 is not practical, but in light, sandy soil 

 I have found it a good protection. If 

 any of you are growing onions in light, 

 sandy soil, it will be well for you to try 

 this, but the chief standby is the carbolic 

 wash. As I have said, however, we have 

 not as yet any practical remedy by which 

 maggots can be entirely prevented ; but 

 in Ottawa, I have grown crops of onions 



A Well-kept and Well-n 

 Home and farm of Geo. S.vnu; 



have your stock emulsion. When you 

 want to use it, mix one quart with loo 

 parts of water and apply as a spraying 

 mixture directly on the plants or pour it 

 along the rows, either with a sprayer 

 or with a watering pot. You can go 

 along the rows of onions as fast as you 

 can walk at an ordinary pace. 



When the young onions first appear 

 above the ground, give them the first 

 treatment and repeat once a week for 

 about four times in the spring. By that 

 time, the first crop should be ready for 

 market and it is not as a rule necessary 

 83 



anaged Market Garden 



& Son, Carlcton Went, Ont. 



and radishes when other people close to 

 me had none. The smell of the carbolic 

 wash keeps away the egg-laying flies. 



FRESH GAS LIME 



An experiment which gave good re- 

 sults in a large fleld of onions where the 

 land had been planted to onions for 

 several seasons and was strongly fertiliz- 

 ed and well kept up and had grew remar- 

 kably good onions for years, was based 

 on the same principle. The onion mag- 

 got appeared suddenly and the whole 

 crop would have been lost, /vfter they 

 had been cleaned thoroughly, the ''ulti- 



