REPORT OF THE STATE ENTOMOLOGIST I9OO 969 



caterpillar are hatching on tree 40. Trees 50-53. The kerosene is hardly 

 apparent, and the trees are budding. 



May 11. Tree 3 is in full bloom (pi. 5), most conclusive evidence 

 that the buds have not been injured by the insecticide. Tree 39 is 

 more backward than 40. The former is much more infested with the 

 scale than the latter. The full bloom of trees 3 and 5 1 is well shown on 

 pi. 5, 7 which were taken May 12, 



May 14. Trees 1, 2, 3. 8-14 are unharmed, the leaves are out well, 

 and the blossoms are numerous. Trees 38-40 are a little more advanced 

 than trees 36 and 37 (treated with 25% kerosene), except tree 39, which 

 is in very bad condition on account of the scale. Tree 50. The leaves 

 are well out, abundant, and the blossoms are about to appear. Trees 

 51-53. The leaves are nearly out, and the rather abundant blossoms are 

 almost past. 



May 28. Tree 39 is in very bad condition, as half of the top is dead, 

 the result in all probability of excessive infestation by the scale. Tree 

 50 is healthy, the foliage is thick and bright green. 



July 2. .The young had evidently begun to appear several days pre- 

 viously, as a number were found in the white stage. The trees were all 

 examined for the presence of living young, this being the surest test of 

 the efficacy of the insecticide. Trees 3, 8-14. Young scales are abund- 

 ant. Tree 38. Living young are comparatively few. Tree 39 had 

 been removed. Tree 40. Living young are numerous. Trees 50-53. 

 Living young are very numerous. This record shows most conclusively 

 that a mechanical, 20% kerosene emulsion will not injure fruit trees when 

 applied just before the buds open, and it also shows, unfortunately, that 

 it does not kill the San Jose scale under these conditions. The young 

 were produced in such large numbers that it was decided to give a sum- 

 mer application. The vigorous condition of tree 8, photographed on this 

 date, is shown on pi. 8 and is there compared with tree 93, which was 

 photographed the same day. 



July 16. This was a dry, very warm, practically clear day and the 

 above listed trees were sprayed with a 10% mechanical kerosene emul- 

 sion. There was a breeze most of the time, and the mixture evaporated 

 very rapidly. In subsequent observations account must be taken of this 

 treatment. 



July 19. The foliage of these trees was practically unaffected by the 

 insecticide, and a large proportion of the tender young scales were killed. 



July 30. On trees 8-10 there were some living young, on trees 11,12, 

 14, 38, 40 and 53 most of the scales were dead, on tree 13 only a part of 



