160 ILLINOIS ACADEMY OF SCIENCE 



fungus is extremely susceptible to unfavorable environ- 

 mental conditions. 



Proper pruning is important in preventing the occur- 

 rence of sooty blotch in fruit trees. Opening the trees 

 to sunshine and air should be the first measure taken to 

 combat the trouble. 



Clinton (1906) reports the sooty blotch as noticeably 

 injurious in Connecticut orchards, ''even where they 

 have been sprayed". With this exception, the fungus has 

 generally been reported easy of control when a regular 

 spray schedule was followed. Usually this control 

 comes about as an incidental result (Scott 1906, and 

 Beach 1912), of other applications of spray material in 

 the schedule. 



The first recorded experimental work carried on for 

 the control of sootj^ blotch was that of Lamson, on pears 

 (1894). He reports that spraying with Bordeaux mix- 

 ture was effective in controlling the trouble. His for- 

 mula was 6 lbs. copper sulfate, 4 lbs. lime, in 22 gallons 

 of water. Lamson 's results, of special value in showing 

 gradations of control, are tabulated as follows : 



Unsprayed 

 Sprayed . . 



Since that time, coincident wdth the gradual improve- 

 ment in the formula for Bordeaux mixture, and more 

 knowledge of its limitations, as well as advantages, in 

 sooty blotch control, other fungicides have been discov- 

 ered and tested. Lamson (1903), with a 5-5-50 Bordeaux 

 mixture, reports that in spraying apples for scab, pri- 

 marily, 77% of the fruit harvested was free from sooty 

 blotch, 23% slightly spotted, and none badly spotted. 

 Selby (1906) suggests an application of 4-4-50 Bordeaux 

 mixture when the apples are the size of hickory nuts. An 

 exception is made in case of apples like the Maiden 

 Blush and Grimes varieties, when the spray should be 

 applied earlier to avoid russetting the fruit. Norton and 

 Se^miour (1907) recommend Bordeaux mixture when the 



