608 NEW JERSEY AGEICULTURAL COLLEGE 



Insecticide Work. 



The worst injury that this scale causes on even a badly-infested tree 

 is a dropping of the leaves and the death of some of the smaller 

 branches, although when abundant it makes a tree unsightly. Often 

 much of the infestation occurs on the lower branches, so that by 

 trimming these out much good can be accomplished. However, in 

 some spots where the infestation was very bad the past season, it was 

 apparent that if we could find a material which could be used to 

 destroy the scale while the trees were in foliage much would be gained, 

 and accordingly several mixtures were tried. 



The first was a "soluble petroleum." In April several twigs with 

 scale in the hibernating stage were in part painted and in part 

 sprayed, at the rate of one part to twenty-five parts of water. Several 

 days afterwards the insects on those twigs which had been painted 

 were somewhat loosened, and the mixture had penetrated beneath 

 them to some extent, while on those which had been sprayed most of 

 the insects appeared to be in good condition. This mixture was again 

 used May 23d, when parts of some elms and sugar maples were 

 sprayed at the rate of one part to twenty, twenty-five and thirty parts 

 of water. When examined several days later all the leaves had been 

 injured to some extent, so that they were more or less brown and 

 curled, especially with the stronger mixtures. The elms suffered less 

 than the m,aples and also recovered more quickly. 



Kill-0-Scale was used June 9th, on a sugar maple, at the rate of 

 one part to twenty-five parts of water, while some limbs on a Norway 

 and on a silver maple were sprayed at the strength of one part to 

 thirty parts of water. A few days later the leaves on the sugar maple 

 were brown and burned, those on the silver maple were brown and 

 curled at the edges, while those on the Norway maple . were only a 

 little spotted. June 10th, a few infested silver maples at Newark 

 were thoroughly sprayed Avith this mixture, at the strength of one part 

 to twenty-five parts of water. Three days later I found that where the 

 trees had been drenched the scales were apparently dead, but the 

 leaves were brown, curled and many had dropped. 



Another soluble oil (Emulsion No. 3) was given a trial June 8th, 

 when a few twigs to which the healthy insects had moved from the 

 leaves were treated, a portion at the rate of one part to twenty-five of 

 water and the rest at the rate of one part to fifteen parts of water. 

 An examination made a few days later proved the insects to be dead. 



