ECONOMIC WORK AGAINST HOWARD SCALE. 91 



(5) Kerosene emulsion, 20 to 30 per cent kerosene, prepared with 

 the use of shiked lime. 



((*)) The patent soluble petroleum spray " Scalecide," used with a 

 5 per cent dilution in cold water. 



(7) " Chloroleum," a new commercially prepared creolin spray, 

 used also with a ;"> per cent dilution in cold water. 



Both spring and fall applications were made with most of these 

 preparations, the spring sprayings being given April 5 and fi and 

 the fall treatments on November 7. 



Without going into the details of the experiment, it may be stated 

 briefly that the lime-sulphur washes were most successful when cost 

 and efficiency were considered. Comparing the results of my work 

 against the Howard scale with my experience with the San Jose 

 scale in Illinois, it was (piite evident that the Howard scale was the 

 more easily controlled. Examination of the structure of the scale 

 covering protecting the Howard scale explains, perhaps, the cause of 

 its greater susceptibility to contact sprays. With the Howard scale 

 the coverings are much more loosely attached to the bark. This gives 

 the spray less resistance in coming into direct contact with the body 

 of the insect concealed beneath. 



All of the lime and sulphur preparations were effective. " Chlo- 

 roleum " did not promise well as an insecticide for this purpose and 

 almost a complete failure was made in attempting to prepare the 

 kerosene emulsion with the use of lime. A dry, finely slaked lime, 

 discarded as a by-product from a local sugar factory, was used, 

 which may have been the cause of its failure. The lime failed com- 

 pletely to properly absorb the oil, and when an attempt was made 

 to agitate the mixture by forcing through a force pump the thick, 

 dougliv mess completely clogged strainer and nozzle. 



" Scalecide,'" on the other hand, gave much promise. It was 

 sprayed in November and consequently the final results are yet 

 unknown. It mu^t be said, however, that the soluble petroleum 

 sprays are most deserving insecticides from the standpoint of both 

 effectiveness and convenience of use, and could their cost and trans- 

 portation expense to the West be lessened they would receive more 

 universal use by orchard men. 



As stated, the lime-sulphur washes were found best adapted for 

 combating this new scale pest. The self-boiled mixtures and those 

 boiled by caustic soda in the experiment were not so satisfactory as 

 the ones ])repared by boiling properly, but the inconvenience of 

 cooking creates a certain demand for a material ready made and 

 possible of innnediate dilution with cold water. The "' Rex " lime- 

 sulphur used in the exi)eriinent was of the latter class. It is a con- 

 centrated lime-sulphur solution formerly used in the West as a stock 



