132 NEW YORK STATE MUSEUM 



some cases at least the plant lice were extremely abundant even 

 to the middle of August. The worse infested trees lost a con- 

 siderable portion of their foliage; the development of the fruit 

 was severely checked in some instances and many trees were seri- 

 ously injured. Complaints were received from a number of cor- 

 respondents in different sections of the State, and almost every 

 observer agreed in holding plant lice responsible for severe dam- 

 age. Some quince bushes in Genesee county were reported by Mr 

 J. F. Rose as bearing a mass of black, rolled leaves the latter part 

 of June, and the observer in Dutchess county characterized the 

 attack as being more severe than had been known for 10 years. 

 The conditions in the nursery were no better than in the orchard, 

 and a correspondent reports that plant lice obliged him to keep 

 a gang of 15 or 20 men and boys at work continuously in the 

 nursery with a whale oil soap solution, and some other nursery- 

 men found themselves almost unable to cope with the insects, so 

 severe and general was the injury. 



Plant lice, as is well known, must be controlled by the use of 

 contact insecticides, the most valuable of which for present pur- 

 poses are a whale oil soap solution, tobacco water and kerosene 

 emulsion. Some growers prefer the tobacco solution to any other 

 and attribute greater effectiveness to it, while others have ob- 

 tained excellent results with a whale oil soap solution. The latter, 

 in the case of the appletree plant louse, should be used at a 

 strength of 1 pound to 6 gallons of water, or even 1 to 4, and in 

 any case great care should be exercised to secure thorough treat- 

 ment. The kerosene emulsion may be used in the same way as 

 the whale oil soap solution, and in case of severe attacks the 

 standard emulsion may be diluted with but 6 or 7 parts of water, 

 since it is better to scorch the foliage a little than to allow many 

 of the insects to escape. 



The severe and protracted injuries by plant lice led us to ex- 

 periment with whale oil soap solution, 1 pound to 4 gallons, for 

 the purpose of testing its effectiveness on the pest and also the 

 liability of injuring the foliage. Apple twigs covered with the 

 insects were dipped into the solution July 28, and on the 30th it 



