CH. Tin.] THE DISEASES OF PLANTS. '^77 



Probably the occasional application of diluted acids, 

 such as the dregs of beer, ^vould mitigate the spn- 

 ptoms, and check the progress of the ulceration ; but 

 the application could not be expected to effect a cure, 

 nor is it available, even if proved to be a specific. 



The warts or galls that may so frequently be no- 

 ticed on the bulbs of turnips, must not be mistaken 

 for the ambury in a mitigated foiTQ. If these are 

 opened, they "will usually be found to contain a yel- 

 lowish maggot, the larva, probably, of some species of 

 c}'nips. This insect deposits its eggs in the turnip 

 when of larger growth than that when it is attacked 

 by the weevil, and the vegetable, consequently, suf- 

 fers less from the injmy; but from slight observa- 

 tions, I am inclined to conclude, that the turnips thus 

 infested suffer most from the frosts of winter, and 

 are the earliest in decay. This is what might be an- 

 ticipated ; for when the maggot has escaped from its 

 cell, the hollow of this admits the exterior air to the 

 wounded vessels, and forms a resen'oir for moisture, 

 agents which promote the progress of putrefaction, 

 and assist the penetrating influence of the freezing 

 temperature. 



Canker. "Wliatever may be the disease under which 

 a plant is suffering, it is too usual for the cultivator 

 to confine his attention to the part immediately af- 

 fected. It is looked upon as a strictly local derange- 

 ment, and the remedies are as erroneously topical. 



