89 



1903*, it had been found in 64 Illinois localities ; and very thoro insec- 

 ticide operations in nearly all of them had exterminated it in only 8. 

 In 1906t, 51 of the 102 counties of the state were known to be 

 more or less infested; but 43 per cent of the infested orchards were 

 in 2 of these counties. Even in these 2 counties the scale had not yet 

 become general, and in 30 of the others listed the average number of 

 infested orchards was only 3}^. 



In 1908 the San Jose scale was known to be present in 79 counties, 

 in 10 of which, all in the southern part of the state, the infestation 

 had become general. In 10 counties it was limited to 3 centers ; in 17 

 counties, to 2 centers ; and in 22 counties, to 1 center. In the same 

 year, 1007 farm orchards lying in two belts, each half a mile wide, 

 one extending north and south, from Rockford to Centralia, and the 

 other east and west, from Danville to East Hannibal, were inspected 

 to see to what extent they were infested by the San Jose scale. Thirty- 

 nine of these orchards or 3.87 per cent, were found infested; from 

 which fact we may infer that about 4 per cent of the farm orchards 

 of the state were infested at that time. 



No attempt has been made since 1908 to collect data of its spread, 

 or to seek out new centers of dispersal. At least eight counties more 

 have nevertheless been added to the list, and it probably might be 

 found to some extent in nearly every county in the state. 



Many southern, and some central and western counties are quite 

 generally infested, and in some of these counties the Osage orange 

 hedges are commonly infested as well as the orchards. The infesta- 

 tion is by no means general, however, in all the southern and western 

 counties. In 1912, of 78 orchards averaging over 1000 trees each, 

 inspected in Pike county, 37 per cent were found infested; of 55 

 orchards in Jefferson county averaging over 500 trees each, 96 per cent ; 

 and of 85 orchards in Wayne county averaging over 600 trees each, 

 14 per cent were infested. The San Jose scale is to be found in prac- 

 tically all the towns and villages of the southern part of tlie state. 

 It has also reached many towns and orchards in northern Illinois, 

 but in much smaller proportion than farther south. It also multiplies 

 less rapidly, and is hence far less destructive, in the northern counties 

 with their cooler climate and shorter growing season. 



*Rep. III. state Ent. on the Horticultural Inspection Law , Nov. 1, 1900*- 

 February 1, 1903. 



fBull. 62, Bur. Ent., U. S. Dept. Agr., p. 23. 



