THE IMPROVED SYSTEM IN USE. 67 



variations as may be fouiul to exist are so small that in practical 

 work in the field the results. in killing scale-insects, from the use or 

 any part of the table, will be found as satisfactory as from the use of 

 any other part. Moderateh' heavy dosages almost invariably burn 

 the tender shoots of a tree to a greater or less extent. Under this 

 schedule practice has demonstrated that the tender growth is uni- 

 formly burned back in all cases, whether large trees or small ones 

 are fumigated. 



As previously stated in this discussion, dosage schedule No. 1 

 was prepared for use against the purple scale at Whittier, Cal., during 

 the latter part of July when the fruits in some orchards were about 

 the size of a walnut. The dosage employed was as great as the fruit 

 would permit at that season without injury. This does not indicate 

 that a larger dosage can not be safely used at other seasons of the 

 year, if desired. The writer has at times employed a dosage of 

 double the strength without visible injury to the trees. This was 

 accompHshed, however, under more favorable conditions, during the 

 fall and winter months, when the fruit was well grown. It is not 

 deemed advisable to use a dosage against the purple scale of less 

 strength than that of schedule No. 1. If complete eradication is 

 tlesired, a much heavier dosage must necessarily be employed. 



The dosage in schedule No. 1 is equivalent to what is known among 

 many fumigators as the " double dosage." It may be a little stronger 

 than the double dosage of some, rather than weaker. "Double 

 dosage" is usually intended to signify a dosage twice the strength 

 required to destroy the black scale in its earHer stages. 



Since this schedule is one of uniformity, it readily permits of 

 manipulation. If a heavier dosage should be desired, such may be 

 obtained by increasing each individual number or dosage in the same 

 ratio; if a lighter dosage, by proportionately decreasing each. The 

 schedule resulting from such increase or decrease mil also be one of 

 the same general uniformity as the first. The writer has prepared 

 schedules which are J, f , 1^, IJ, and 1^^ times the dosage indicated 

 in schedule No. 1. 



THE IMPROVED SYSTEM IX USE. 



Two outfits of the Whittier (Cal.) Citrus Association commenced 

 the use of this improved system of fumigation, with dosage schedule 

 No. 1, during the latter part of July, 1908. The apparent uniformity 

 of work, indicated by the evenness with which the tender growth 

 was burned back on all trees, immediately attracted the attention 

 of citrus growers who saw the fumigated orchards. Their universal 

 approval of the method is shown by the fact that not a single unfa- 

 vorable comment was brought to the writer's attention throughout 

 the entire fumigation work. The reception of an improved method 



