602 STATE BOARD OF AGRICULTURE. 



When the flame is passed over the body of a scale-coated tree, the scales 

 instantly change color and many drop off. If rubbed the scale is seen to 

 be loosened and on examination with a lens shows minute lines resemb- 

 ling cracks running in all directions over the surface. Now the trunk and 

 larger limbs of trees are often covered several layers deep with the scales 

 and in such cases this method of treatment seems useful. It destroys 

 most of the insects and so loosens the mass that it is possible afterwards 

 to penetrate to the bottom with a spray. The heat produced by this lamp 

 is very intense and great care must be observed not to allow the flame to 

 remain at any one point long enough to injure the tree. In the experi- 

 ments tried, the best results were obtained when the flame was steadily 

 moved so that it covered a space of a yard in length in from five to ten 

 seconds. The trials were made on peach and pear trees badly affected 

 with the San Jose" scale, and during the winter months while the trees 

 were dormant. The results seemed to show that the blast will kill the 

 scale-insects with little or no injury to the tree; the trees were scorched in 

 places where the flame had moved too slowly and the care necessary to 

 avoid the scorching appears to be the most serious drawback to the use of 

 the blast-lamp. In careless hands much injury may be done in a very 

 short time while the skilful handling necessary for success would be 

 rather expensive under ordinary circumstances. Good judgment must be 

 exercised always and the rapidity aud effectiveness of the work will be 

 much modified by the temperature of the air, the direction and force of 

 the wind, the age of the tree and the thickness of the encrusting scales. 

 Under favorable conditions we believe the blast-lamp can be used to good 

 purpose and economically in destroying scale-insects, but we are not pre- 

 pared to recommend it for general use as superior or even equal to treat- 

 ment by spraying. 



