Insects and Preventives 



are fully in bloom. The importance of this early and continuous fumigation 

 must not be lost sight of. The aphis having once become well established 

 upon the plants, will frequently maintain themselves throughout the entire 

 winter, in spite of continued fumigation. But if the first colonies that de- 

 velop after the plants are brought into the houses are promptly destroyed, 

 the succeeding colonies will diminish, and the insects will not multiply to 

 an injurious extent, provided the houses are fumigated once each week until 

 the plants are in bloom. At this period it is well to cease burning tobacco 

 stems, for the reason that fumes injure the flowers, destroying the natural 

 odor ; they also impair the keeping qualities of the blooms to some extent, as 

 well as bleach the colors. 



From this period blooming plants should be kept free from aphis by 

 using some one of the mixtures of tobacco extract. The substance employed 

 may be applied to the steam pipes, having it of the consistency of paint and 

 brushing it on the pipes thoroughly during the daytime while the pipes are 

 still cool. When the steam is turned on at night the fumes of the tobacco 

 extract will be given off, and if sufficient pipe surface is covered with the 

 extract it proves as efficient in destroying aphides as the more objectionable 

 method of burning tobacco stems. 



The extract may also be evaporated from pans attached to the steam 

 pipes. The extract may also be evaporated by boiling it in shallow dishes 

 upon an ordinary oil stove. 



If the grower will treat his plants to thorough fumigation once or twice 

 a week from the time they have become well established until they are in 

 bloom, and then follow up with a weekly fumigation with the tobacco extract, 

 it is probable that no aphis will be seen during the winter, unless the plants 

 when brought in from the field were thoroughly infested with the insects. 



In order to guard against the stock being attacked in the field during 

 the summer, it is essential that the young plants be treated to fumigation at 

 least once a week, up to the time they are to be planted out. The week 

 previous to setting the plants in the field, we follow the practice of fumigating 

 the young stock every other night, so as to insure killing all the insects 

 which may have escaped previous fumigation. 



Red Spider 



One of the most difficult insects to hold in check is the red spider 

 (Tetranychus telarius). This pernicious little mite seems to be unaffected by 

 all of the tobacco remedies which prove efficacious in the case of the aphides. 



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