no 



Illinois Natural History Survey Bulletin 



Vol. 27. Art. 



contrast, we find that in sprayed orchards 

 0.03 to 7.6 per cent, or an average of 2.2 

 per cent, of the fruit is womiy. Thus, we 

 find that, in spite of adversities and re- 

 verses, continued research has developed 

 control measures that have enabled apple 

 growers to reduce the percentage of 



a dozen important scale insects alone. 

 One scale insect of great importance is 

 the San Jose scale, which was introduced 

 into California from China about 1880 

 and into Illinois about 1895. For a time 

 this scale threatened to wipe out the Illi- 

 nois commercial fruit industrv. Parasites, 



>pray;r.g equipment designed and used aDout lsy7 Dy tde Mate Entomologist and his assist- 

 ants for experiments on control of San Jose scale. '"The principal apparatus used is a large and 

 complicated machine sprayer consisting of a one-horse power gasoline engine, a three-cylinder 

 force pump, and a large double galvanized-iron tank with a powerful gasoline heater beneath 

 for making the solution of whale-oil soap" (Forbes 1900:14j|. The sprayer was mounted on a 

 r»To-horse baggage wagon. 



worm-damaged apples from possibly 60 to 

 100 per cent in 1867 to 21 per cent in 

 1885. 4.4 per cent in 1915, and 2,2 per 

 cent in 1957. 



If it appears that entomologists have 

 devoted too much attention to this one 

 insect, let us recall that codling moth re- 

 search has been the traditional guinea pig 

 for the study of many insect control pro- 

 cedures, and that the measures developed 

 for the control of the codling moth for 

 the most part have given satisfacton con- 

 trol of a considerable number of other 

 pests of apples. 



A list of the insects attacking fruit 

 crops in Illinois would no doubt include 

 100 or more species. There are at least 



predators, and diseases have played an im- 

 portant role in holding this insect at bay, 

 but for over 50 years orchardists have 

 found it necessary to apply a dormant 

 spray or some other special treatment to 

 bring this insect under control. As late 

 as 1950, Illinois apple growers seemed to 

 agree that if the use of sprays was to be 

 forbidden San Jose scale would eliminate 

 commercial orchards within 5 years. This 

 insect, perhaps more than any other, has 

 been responsible for the development of a 

 strong plant inspection and quarantine 

 system in Illinois, and. for that matter, 

 in other states as well. Here we have an 

 insect that can barely survive on wild or 

 neglected trees but that thrives on young. 



