The Cabbage Root Maggot. 557 



was poured into a cavity about the base of the plant as in the experiments 



above ; in one cage nearly ^ of the maggots were near the surface and thus 



got a thorough soaking. In 2 or 3 days a superficial examination showed 



that a few maggots had been killed, and many had not, but both plants were 



considerably injured by the solution. To further test the effect of this strong 



solution on the plant, it was applied to plants having no maggots on their 



roots. June 6 all of the cages were carefully examined. Sixty-four live 



pupae, many of them recently formed, were found in one and 50 in the other 



cage. The plants were all badly injured by the solution. The same check 



cages were used as in the preceding experiments. 



We do not offer these experiments as conclusive evidence that kainit will 



not always kill the Cabbage Root Maggot. But the results do show that it will 



not always kill the majority of the maggots even when used strong enough 



to badly injure the plants. Thus, from the evidence submitted, we cannot 



escape the general conclusion that it would be well to first definitely settle, 



by careful experiments, whether kainit will kill a majority of the maggots 



when used in practicable amounts, before we recommend it to gardeners for 



this purpose.* 



Salt. 



The first record we find of the use of salt as a destructive agent against 

 root maggots is in 1877, when Mr. Garfield of Michigan partially removed 

 the soil from the roots of infested cabbages, then salt was thrown in and 

 covered up ; "it soon dissolved, but to no purpose." In i88i,Miss Ormerod 

 reports that a solution of salt saved but a few plants. A solution of salt at 

 the rate of 4 oz. to one gallon was tested by Mr. Goff in 1889 ; " it produced 

 no Arisible effect. ' ' Mr. Fletcher recently reported conflicting results from 

 its use against the maggots. 



* Although we do thus doubt the insecticidal qualities of kainit when used against the 

 root maggots in practicable quantities, we do not wish to discourage its use by gardeners 

 for fertilizing purposes. And yet, as Mr. Wright Rives, of Washington, D. C, has so terse- 

 ly expressed it in a recent letter to us, " I want potash, not salt ; therefore I do not use 

 kainit." In some cases these commercial fertilizers may furnish to the plants, just at the 

 right time, the food needed to enable them to outgrow the injury caused by the insect. 

 But, the insect still remains a constant menace to the gardener. Mr. Fletcher showed in 

 1890 that "the power of the cabbage plant to survive and outgrow injury is very remarka- 

 ble. Several plants of which the roots and nearly all the underground stems had been 

 destroyed, were washed and trimmed, and then planted and watered, and the earth 

 kept well hoed up around them. Every one of these grew and produced a head. In years 

 of only light attack it is not at all uncommon to find when cabbages are pulled up, that they 

 bad been supported by roots which were produced some distance above the root-mass, 

 which had been destroyed early in the season by the cabbage maggot." There are several 

 accounts of the use of commercial fertilizers on plants infested with the root maggots, but 

 with no claim of having saved the crop by the maggots having been thus destroyed. As 

 Peter Henderson expressed it when he used guano and lime : Strong roots were made 

 above the wounds, and thus the crops were saved ; it would have failed to be effective if 

 the ravages of the maggots had been far advanced. We have discussed the insecticidal 

 value of commercial fertilizers at some length in answer to several correspondents in the 

 "Rural New Yorker" for March 24, 1894, p.184. Prof. J. B. Smith stated his views on 

 the same subject in a note in the same paper for April 28, 1894. 



