546 Bulletin 78. 



the attack arrived it appeared that the plants of the plat were all sufFering, 

 and an examination made June i8, showed that twelve plants treated with 

 the lime had sixty-six maggots, while eleven plants not treated had but 

 twenty-four maggots, proving conclusively the ineflfectiveness of the ap- 

 plication." 



It thus seems to us from a critical survey of all the evidence we can find, 

 that gardeners can not expect to prevent the attacks of the Cabbage Fly by 

 the use of lime ; its use as a destructive agent is discussed further on. 



Salt. 



Mr. Will {^Country Gentleman for 1879, p. 167) and Mr. Hewes (ibid, for 

 1880, p. 39) claim to have had good results from the use of salt applied, in 

 the hole in which the plant is to be set or on the surface around the newly 

 set plant, to prevent the Cabbage Fly. Mr. West (ibid, for 1880, p. 470) used 

 salt at the rate of three bushels per acre on a small bed at the time of setting 

 the plants; he lost one-third of his crop. Doubtless the salt, thus applied, if 

 it had any effect, would act by destroying the young maggots. Its destruc- 

 tive power is discussed farther on. 



Salt and Lime. — A recommendation to mix salt and lime with the soil 

 previous to sowing the seed or apply it to the surface after sowing, has found 

 its way into the literature of root maggots. In 1843, Curtis quoted such a 

 recommendation by a Mr. Sinclair, but it was to prevent the attacks of the 

 Turnip Root Gall Weevil mentioned on a preceding page. As the separate 

 use of these substances has not been attended with very favorable results as 

 preventives, their combination would doubtless be no more effective. 



Barn Manures. 



So far as we know, stable manure has never been recommended as a pre- 

 ventive of this pest, but as it is one of the substances frequently applied to 

 the soil by farmers, and as it doubtless affects the insect in a certain way, it 

 seems best to discuss it in this connection. 



When Bouche described the Cabbage Fly in 1833, he said that the avoiding 

 of the use of new dung was of no avail ; and this statement has been em- 

 phasized by almost every writer since. In fact, many prominent writers, 

 including Curtis, Miss Ormerod, Lintner, Fletcher, and Henderson, all con- 

 clude that fresh manure attracts the flies and thus encourages, rather than 

 prevents the attacks of the pest. This idea is well supported by several ex- 

 periments recorded by gardeners. Thus, the use of fresh barn manures are 

 to be avoided on crops attacked by root maggots ; even where well-rotted 

 manure is used the maggots seem to be more numerous. This is doubtless 

 one reason why the commercial fertilizers are now largely used by gardeners. 

 The probable reasons why the barn manures attract the pest are discussed on 

 a preceding page under the food-plants of the insect. 



Commercial Fertilizers. 

 Ashes. — In 1857, unleached ashes were used in Maryland without success 

 {Country Gentleman, p. 319). Mr. Goff reported in 1885 that two years be- 



