382 Tobacco Growing for Insecticidal Purposes, [aug., 



Shelter, — The question of shelter is a very important one. 

 Only land which is naturally well sheltered from wind should 

 be selected for the growing of tobacco. A single stormy 

 night may do an immense amount of damage to the crop 

 unless it is well protected. Where natural wind breaks 

 cannot be obtained, artificial ones, such as hop lewing or a 

 belt of some tall luxuriant plants, e.g., Kentucky hemp, 

 artichokes, climbing haricot beans, or Ne Plus Ultra peas, 

 must be used. 



Weeding. — The land must be kept scrupulously clean in 

 the early stages of growth, because by the middle of July 

 the leaves of the plants will begin to overlap, making horse- 

 hoeing impossible, whilst even hand-hoeing will have to be 

 abandoned about a month later. All weeds must therefore 

 be removed while the plants are still yolmg. 



Topping. — When the plants have developed about a dozen 

 good leaves the whole top of the plant must be removed. 

 This operation is known as "topping," and has for its object 

 the prevention of seeding and the concentration of the entire 

 energy of the plant into developing to the full those ten or 

 twelve leaves that remain. Topping is nearly always carried 

 out with smoking tobaccos, and it is found to be even more 

 necessary where nicotine is the object in view. A few large 

 well-grown leaves were found at Wye to contain 2j- times 

 as much nicotine as a larger weight of small leaves left on 

 another plant growing under the same conditions but left 

 untopped. 



The effect of breaking off the stem of the plant is to cause 

 development of shoots in the axils of the remaining leaves. 

 These are known as suckers," and they have to be removed 

 by hand as fast as they appear. In the case of smoking 

 tobaccos suckering is done once a week from the time of 

 topping to the time of harvesting, and probably it pays to do 

 it just as often in the case of tobacco grown for nicotine 

 extraction. The work can quite well be done by a boy, but 

 it is nevertheless an expensive operation, costing about five 

 shillings an acre every time it is done. 



Harvesting. — ^By the beginning of September the plants 

 should be ready for harvesting. It is very important not to 

 cut too early as the nicotine content increases very rapidly 



