37 



rapid increase of the scale, which, when present, requires treat- 

 ment by man in addition, if the infested plants are to be kept 

 from entire destruction. 



Treatment. 



The methods of treatment for the San Jos6 scale successfully 

 used on the Pacific coast have thus far failed in the eastern United 

 States, where they are " fatal to only a small percentage of 

 scales." Why this is the case it is difficult to say. In California 

 the treatment is applied some little time before the rainy season, 

 which gives an opportunity for its action before being washed off 

 by the rains. In the east, however, this treatment must be ap- 

 plied at times when rains are frequent, and it may be that in this 

 fact is found the reason why the treatment is a failure in this part 

 of the country. 



The San Jos^^ scale is a sucking insect ; consequently, neither 

 Paris green, arsenate of lead or any of the so-called " stomach 

 poisons " are of the slightest use. The treatment which will kill 

 it must be something which kills by coming in contact with it ; and, 

 as the insect, except in its earliest stages, is covered by a hard 

 scale, the treatment must be by the application of some substance 

 caustic enough to eat or corrode the scale and penetrate to the 

 body of the insect beneath. Spraying with kerosene emulsion 

 will kill the young insects, of course ; but, as these appear every 

 few days from some time in June until November or even Decem- 

 ber in some cases, this would mean that the infested trees must 

 be sprayed at least once a week during this entire time, which is 

 also the time during which it is most difficult to reach all parts of 

 the tree thoroughly, on account of the foliage. Accordingly, 

 treatment during the winter months is the best. 



Destruction of Trees infested. 

 In cases where the scale has just appeared, or but few trees arc 

 infested, the cheapest and safest treatment is to cut down and 

 burn those trees. If a tree be thoroughly covered with the scale, 

 burning is also the best treatment, as it will be almost impossible 

 to clear such a tree sufficiently to make it valuable for its product, 

 while it would be a constant menace to all other trees around. 

 The sooner a badly infested tree is destroyed the better. 



Kerosene. 

 During the winter nionlhs, while the trees are not growing, 

 ranch stronger materials can be used for treatment than during 

 the growing season. This is particularly the case between the 



