71 



utter destruction was only a question of time unless some means could 

 be adopted to annihilate the insects. 



This means has been adopted. It consists simply in covering the 

 floor of the house with tobacco-stems, the refuse of cigar manufactories; 

 this mulching proves quite effectual, as, since the application was made, 

 no thrips have been seen, and, although the insect has spread consid- 

 erably before the tobacco-stems were used, they rapidly disappeared 

 after the application. 



It is perhaps worthy of remark that since using the tobacco mulch- 

 ing no sign of mildew has been observed on the grapes. Of course it 

 is known that mildew may be avoided by strict attention to ventilation, 

 but in the early part of the season, when the ventilators have to be 

 closed at night and opened during the morning, it is not always prac- 

 ticable to prevent cold currents of air from striking some portions of 

 the foliage, a circumstance which will induce fungus growths on the 

 leaves ; not the slightest indication of mildew has been observed since 

 the tobacco-stems were sprinkled over the floor. 



PKOPAGATING BY CUTTINGS. 



To be successful in any pursuit it is very necessary that we should 

 be conversant with the rationale upon which our operations are 

 founded, and in no horticultural process does this apply with so much 

 force as in plant propagation by cuttings. 



There is, however, much in connection with this subject that remains 

 unexplained. We know not why it is that some plants will propagate 

 readily, while others, seemingly of similar structure, with the greatest 

 tardiness and difficulty. 



A cutting may be described as a portion of the branch of a plant that 

 is removed and placed in a position to form roots, so as to become an 

 independent individual, possessing all the properties and being a liv- 

 ing representation of the original from which it was taken. Cuttings 

 are of various kinds. Young, tender shoots, perfectly matured growths, 

 and wood in all stages of maturity intermediate between these ex- 

 tremes are used for cuttings. 



The best condition of wood growth also varies with the kind of plant. 

 This is a question that can only be ascertained by experiment. We 

 know of no external appearance that will indicate the special propor- 

 tionate arrangement of the constituents of plants most favorable for 

 the formation of roots from cuttings. 



As an extension of roots is dependent upon the previous or simul- 

 taneous action of foliage, it is found that in general the best shoots 

 for propagation are those possessing a considerable portion of the or- 

 ganized matter consequent upon a ripening of wood growth, but in 

 which the process of vegetation is still in full operation ; in other 

 words, those shoots that have commenced to mature, but are still 



