96 MAINE AGRICULTURAL LXPERIMEXT STATION. I903. 



both inexpensive and inodorous, and at first did not appear to 

 cause the sHghtest injury to the plants. The soap was cut in 

 thin shces, then dissolved in hot water, and cold water added to 

 make the right proportions. The plants received one application 

 each week for about three months, when some of the leaves 

 finally exhibited signs of injury. ■'>-■■ 



''As the plants had never been sprinkled with water from the 

 hose and had received frequent applications of soap, the leaves 

 finally became coated over with soap to such an extent as to inter- 

 fere seriously with the normal processes of respiration. The 

 lower leaves in- some cases shriveled and dropped. A- few spray- 

 ings cause no injury, and probably none w^ould be done in any- 

 case if the plants are sprinkled freely with water to remove the 

 excess of soap. 



"The chief difficulty with sprays of any kind is that it is impos- 

 sible to reach all places where the insects are located. Many 

 leaves are curled so that the spray cannot reach the under side, 

 and there are always- portons of the plants which do not, on 

 account of location perhaps, receive a thorough treatment ; this 

 permits the escape of a sufficient number of adults, or of nymphs 

 which soon change to adults, to keep the house infected. •■ 



"Fumigating. — Furrtigating with tobacco is the remedy that 

 has been oftenest recommended for this insect, but the fumes 

 from the burning of ordinary stems or dust do not kill any con- 

 siderable number of the insects. ]\Iany are stupefied by the 

 fumes and fall from the plants, but revive later and soon become 

 as active as ever. During the past two or three years tobacco 

 used in this way seems- to hav^ been less effective in destroying 

 the adults than when the writer first employed it eight years ago.' 

 Where the adults are stupefied and fall to the ground a copious 

 watering of the surface of the soil will kill them in great num- 

 bers.".;. . iJ /[),i. :t - • 



At this Station fumigation with hyrocyanic acid gas is the 

 most successful remedy tried. The gas was made with a half 

 more strong sulphuric acid (liquid measure) than the weight of 

 cyanide, and a half more water than acid.- The jar containing 

 the dilute acid was placed on the f^oor of the house, and the 

 cyanide of potassium- which had been put into- a paper bag, 

 weighed, and suspended over the jar, was dropped into the acid. 

 This treatment is in accordance with the suggestions by John- 



