98 



marks," though in general it is entirely dissimilar. Should it prove 

 to be the same, there must be a very enormous and decidedly remark- 

 able mortality of the winged females migrating from the apple in 

 May, for which there seems no good reason. 



Aphis pomi DeG. seems more abundant than usual this year and 

 becoming more widely distributed. It is unquestionably one of the 

 worst insect pests of the young apple orchard and of old trees being 

 top- worked, and how best to combat it is somewhat of a problem. 

 It should be noted that some varieties of apples are decidedly prefer- 

 red to others by^ the aphides, trees of another variety next to badly 

 infested trees often remaining unmolested. Very frequently this 

 season I have found colonies of this species of a bright orange-yellow 

 color instead of the typical bright green, and also intermixed with 

 the green forms. This striking variation has not been previously 

 observed so far as recorded, and I regret that I have been unable to 

 ascertain whether the yellow aphides reproduce the yellow form. 



Owing to the manner in which they curl the leaves, Aphis sorbi and 

 pomi are exceedingly difficult to combat; Aphis fitchii rarely does 

 sufficient damage to warrant treatment. Washes of whale-oil soap, 2 

 pounds to a gallon of water, and lye 6 pounds to 50 gallons have both 

 failed to destroy the eggs. Prof. Aldrich reports having killed the 

 eggs with 33 per cent crude petroleum with water, using a heavy 

 western oil of .954 specific gravity. We have sprayed several young- 

 trees with pure crude petroleum ("insecticide oil"), and though there 

 seemed to be fewer young aphides on these trees, there were enough 

 to soon stock the tree with lice. It seemed probable that the gummy 

 residue left upon the surface of the bark was fatal to many of the 

 newly hatched lice, as the crude oil had undoubtedly had a beneficial 

 effect. 



Fifteen per cent kerosene mixed with either water or Bordeaux 

 mixture has not proven very satisfactory for destroying the aphides; 

 20 per cent kerosene seems more effectual and fairly satisfactory; 15 

 or 20 per cent crude petroleum is quite effectual and does no injury to 

 the trees. When mixed with Bordeaux mixture it tends to make the 

 latter collect in drops, and this is therefore an undesirable combina- 

 tion. Kerosene mixed with Bordeaux mixture and Paris green gives 

 as even a coat upon the foliage as without the kerosene, and would 

 seemingly form a perfect insecticide and fungicide where it can be 

 used to advantage. 



I am inclined to the view that in many cases the kerosene sprays 

 are not effectual owing to the improper working of the pump. Kero- 

 sene emulsion made with soap and diluted to contain 15 per cent kero- 

 sene has failed to destroy the lice. Whale-oil soap, 1 pound to 6 and 

 8 gallons of water was ineffectual, though 1 pound to 7 gallons was 

 fairly satisfactory. The latter is rather too strong, however, to use 



