128 JOURNAL OF ECONOMIC ENTOMOLOGY [VoL 2 



had been inspected two years before, but no scale had been found, 

 altho the infection must have then existed, as no trees were after 

 that set in the block and the possibility of infection from surrounding . 

 territory seemed to be excluded. 



In all the above cases, the scale when discovered was in a thriving 

 condition and it was evident that it was only a question of time, unless 

 treatment were given, when the trees would be entirely destroyed. 

 The Decatur County infection was discovered in the early spring of 

 1901. It was sprayed with whale oil soap in April of that year and 

 with sulfur-lime mixture in the spring of 1902. Complete eradication 

 of the scale, as was proven by annual inspection for four years after- 

 wards, was the result. The Lee County infection was discovered in 

 May, 1906. It was kept fairly well in check during that summer 

 by two sprayings, with a third upon some trees, with kerosene emul- 

 sion. It was sprayed in the spring of 1907 with sulfur-lime mixture. 

 The work was done by the owner and, as inspection soon after 

 showed, the trees had not been entirely covered. By autumn many 

 trees were again badly infested. In the spring of 1908 this orchard 

 was again, and this time carefully, sprayed with lime-sulfur. In- 

 spection this autumn (1908) shows that the treatment was not effect- 

 ive in exterminating, altho the number found on any tree that had 

 been sprayed was very small. One peach tree quite distant from the 

 orchard sprayed, and the only tree on the place that had not been 

 treated, was found this fall to be thickly covered with the scale. This 

 tree had been inspected in the spring and no scale found upon it. 

 It seems evident that the sulfur-lime remained upon the sprayed trees 

 in sufficient amounts during a -considerable part of the summer to • 

 prevent the establishment and rapid multiplication of the scale. The 

 other two cases of orchard infection have been discovered during the 

 present autumn and no treatment has yet been applied. In the case 

 of the nursery, everything found infected and near the infected stock 

 was cut out and burned ; and as this nursery had for two years been 

 establishing itself on new grounds several miles away, it is hoped that 

 complete eradication has been accomplished. 



Perhaps greater interest attaches to the question as to how certain 

 Iowa grown nursery trees on which the scale has been found became 

 infested. Several shipments from Iowa have been found by inspec- 

 tors in other states infested with San Jose scale. In all but two cases, 

 these trees have been traced back and found to have been shipped into 

 Iowa from nurseries in other states. In two cases, however, the trees 

 were grown in large nurseries in the southwestern part of Iowa far 

 removed from anv known infestation. In one case a few scattered 



