20 



green long after unsprayed trees are defoliated. This was true of all 

 the demonstration blocks in the Ozarks during the past season. The 

 unsprayed trees began to shed their leaves in July and were practi- 

 cally defoliated by the last of August, a month before the tune to pick 



the crop. 



RECOMMENDATIONS. 



The treatment recommended for bitter-rot and apple blotch will 

 largely prevent these leaf troubles and hold the foliage m good condi- 

 tion until frost. It is true that some of the leaves become affected 

 soon after they unfold in the spring, but the trouble does not usually 

 become serious before midsummer, and the four applications of Bor- 

 deaux mixture for bitter-rot at intervals of two to three weeks, begin- 

 nmg about six weeks after the blossoms are shed, appear to give 

 reasonable protection. However, the earlier applications usually 

 necessary for the control of a])ple scab and the codlmg moth aid in 

 the control of leaf-spot diseases, and when these are matle, only one or 

 two of the later sprayings are necessary. When it is desired to spray 

 for leaf-spot diseases only, the first application should be made about 

 two or three weeks after the petals have fallen, and a second about 

 seven weeks later. These two applications, if thoroughly made, will 

 usually hold the foliage in good condition. 



APPLE SCAB. 

 INJURY. 



The apple crop of the United States suffers a greater loss by far 

 from the attacks of scab, caused by Venturia insequalis (Cke.) Ader, 

 than from any other fungous disease to which this fruit is subject. It 

 often affects 50 to 75 per cent of the crop over wide areas, and is not 

 infrequently responsible for total failures by killing the young fruits 

 when in blossom or soon thereafter, and by rendering the fiuit too 

 unsightly for the market. 



Scab has a wide distribution, being exceedingly serious in New 



England, the IMiddle Atlantic States, the ^Mississippi and Ohio valle5^s, 



and the Pacific Northwest. In these regions it is almost impossible 



to obtain crops reasonabl}" free from scab without sprajnng. Indeed, 



so great is the damage done by this finigus and the codling moth 



that the percentage of strictly first-class fruit placed on the market 



is quite small, the great bulk of the crop, as a rule, being only second 



class. 



DESCRIPTION. 



The scabby spots that appear on the fruit are so familiar to apple 

 growers that a description here is almost superfluous. They are 

 circular, rough, somewhat irregular in outline, grayish or olive-green 



283 



