408 Agricultural Experiment Station, Ithaca, N. Y. 



tirely free from such attacks, but they form isolated exceptions 

 to a very general rule. All who have had any experience in 

 growing plants under glass know that diseases are sure to appear 

 and that insects will originate apparently from nothing. Indeed, so 

 certain are these pests to appear that every thorough gardener is at 

 all times prepared for them, or even takes steps toward their de- 

 struction before they have been seen. Fortunately, he has at his 

 command abundant means of ^^rotecting his plants, and houses in 

 which insects and fungi are found in large numbers are silent but 

 convincing witnesses of bad management and neglect. When a 

 greenhouse has once become thoroughly infested, it is almost im- 

 possible to rid the plants of their parasites, and it requires constant 

 and prolonged attention to bring about this result ; and even when 

 this has been done, the plants will in many cases have become 

 so weakened that they will scarcely repay the time and labor em- 

 ployed in saving them. The care of plants should begin before 

 they are attacked, and this care should be given uninterruptedly. 

 By treating apparently uninfested plants many invisible enemies 

 may be destroyed, and such treatments are by far the most valuable 

 ones. 



Tobacco. — Several of the most common and often very serious 

 organisms may be overcome by vapors with which a house may be 

 filled, and the best known and the most valuable remedy of this 

 nature is undoubtedly tobacco. The poisonous alkaloids found in 

 the tobacco plant are fatal to many insects. The waste parts of the 

 plants, particularly the " stems," are utilized by florists and others 

 for purposes of fumigation. 



These stems, which are almost invariably the dried mid-veins of 

 the leaves, may be obtained for almost nothing at any cigar factory. 

 "When wanted for fumigating purposes they should not be too dry^ 

 else they will blaze, instead of slowly smouldering and forming a 

 dense smoke. In case the stems are too dry, they may be moistened 

 by sprinkling water upon them ; a better way, however, is to store 

 the stems in a moderately damp place, and then they are always in 

 good condition for burning. If they blaze while the house is bein g 

 fumigated, much of their value is lost, and it is also said that plants 

 are positively injured in sucti cases, although our experience has not 

 supported this view. 



Tobacco stems may be burned in a variety of ways. Some gar- 

 deners merely pile the required quantity upon a brick or stone 



