544 Bulletin 78. 



tested, but which we are inclined to believe will not prove eflfec- 

 tive or practicable. However, there are several methods in this 

 latter group that should receive further investigation as is indi- 

 cated in the conclusions drawn from the evidence submitted in 

 the discussion of each. 



A. PREVENTIVE. 



I. By Ordinary Farm Methods. 



{a) Selection of Soil. 



In 1886, the Rural New- Yorker, advised a correspondent to select a very 

 sandy soil for a radish bed, to avoid injury from the maggot. The 

 next year, in the same periodical, Mr. Goff gave similar advice. Yet Dr. 

 Lintner said in 1882 that " the insect has been observed to be very injurious 

 to earlier crops and upon sandy soil. It is thought that benefit has been de- 

 rived from late sowing in clayey soil." We see no reason why the sandy soil 

 would prevent or discourage the pest in any way. The soil in many parts 

 of Long Island where the maggots work freely is quite sandy. The efiicacy 

 of the method is thus doubtful. 



{b) Time of Planting. 



Our discussion of the number of broods of this pest indicates that in some 

 localities the first brood is not numerous enough to be noticeably destruc- 

 tive, while the second brood is often very destructive. This seems especially 

 true in Canada. Hence, we find Mr. Fletcher and Mr. Fyles advising Cana- 

 dian gardeners to sow radishes early, in May ; but the former writer adds 

 that this will not always prevent. 



Farther south, in our State, all gardeners are aware that the pest is usually 

 the most destructive to early crops. Hence, we find Cook in 1874, andLintner 

 in 1882, advising late sowing of radishes. In New York State, the pest rarely 

 does much damage after July i, so that gardeners find that late cabbages set at 

 about this time escape with little injury from the maggots. In Canada also, 

 Mr. Fletcher finds that cabbages set about July 15 are not troubled by the 

 maggots. The application of the method then seems to depend upon the 

 locality, as far as early crops are concerned, while late crops suffer but little 

 in any locality. However, in many localities and especially on Long Island, 

 it is the early crops that pay the best and are therefore the more largely 

 grown ; so that the time of planting is necessarily early, and the pest must 

 thus be fought by other methods. 



[c) Trap Crops. 



In 1888, Prof. Cook concluded that the Cabbage Root Maggot relished 

 radishes better tham cabbages, and he therefore suggested that the latter might 

 be preseerved from attack by alternate rows of radishes. This, of course, 



