410 Agricultural Experiment Station, Ithaca, N. Y. 



must be insufficient to hurt the most tender plants. Less injury is 

 apt to result if the houses and plants are dry ; wet foliage is quite 

 easily scorched by the smoke. Onr method of starting a " smudge" 

 is to place a single sheet of newspaper, previously lighted, in the 

 bottom of the burner, and upon this the stems are immediately 

 placed. If properly dampened, they will take fire readily and 

 smoulder without blazing. 



The frequency with which a house should be smoked cannot be 

 definitely stated. Some conservatories will require the operation 

 scarcely more than two or three times during the winter, while 

 others may need that many treatments each week. In the latter 

 case, it is well to have the smudges upon consecutive days, as in this 

 manner insects receive a second treatment before they have recovered 

 from the first. The evening is perhaps the best time for fumi- 

 gating, as most of the disagreeable odor is thus escaped. But it may 

 be advisable, in badly infested houses, to follow the evening treat- 

 ment by another the next morning. In such cases, care should be 

 exercised that the houses do not become overheated by the morning 

 sun. 



Tobacco smoke may be used successfully in the destniction of the 

 various aphides which are found upon greenhouse plants, and of a 

 small white fly, a species of aleyrodes. Other insects can not be 

 practically treated by its use. 



Bisulphide of carbon has recently assumed a prominent position 

 as an effective insecticide. It is a clear, transparent liquid, which 

 evaporates rapidly even at a low temperature. These fumes are 

 fatal to insect as well as animal life, and it may be used to a 

 limited extent in the greenhouse. The vapor is of greatest value in 

 destroying a small mite {Tetranychus himaculatus) that closely 

 resembles the red spider. This mite is not as easily overcome by 

 water as is the red spider, and in certain cases it may be advisable 

 to resort to the bisulphide of carbon treatment. This treatment is 

 adapted to plants which are growing in pots or to low growing 

 plants in beds. Whole houses could scarcely be treated in this 

 manner, as the vapor is heavy and an uneven distribution would 

 probably result. But for small, confined spaces, as bell jars, tubs 

 or barrels, the remedy can be used with success. I have had no 

 difiiculty in destroying mites and red spider by the use of 60 minims 

 or drops of the liquid to a space containing about 7 cubic feet. The 

 liquid was poured on cotton batting, which was spread over a small 



