DISEASES OF CULTIVATED PLANTS 459 



very little or not at all in most southern sections. This application 

 also constitutes the treatment for the spring canker -worm. 



Second Application. Immediately after the petals fall. The 

 work may be commenced when about two-thirds of the petals have 

 dropped and should be finished within a week or ten days, that is, 

 before the calyx lobes close. This constitutes the second application 

 for scab and the first for the codling moth and is the most important 

 treatment for both. 



Third Application. Three to four weeks after the petals have 

 fallen. This ib the first and most important application for apple 

 blotch and is the second treatment for the codling moth. 



Fourth Application. Eight to nine weeks after the petals have 

 fallen, or not later than June 25. This is the first treatment for 

 bitter-rot, the second for blotch, and the third for the codling moth. 



Fifth Application. Two to three weeks after the fourth applica- 

 tion. This is the second treatment for bitter-rot, the third for blotch, 

 and is also important for the codling moth. 



Sixth Application. Three weeks after the fifth application. 

 This is the last treatment for bitter-rot and blotch and is important to 

 prevent kte infections. It is also very important for the control of 

 the second brood of the codling moth. 



The course of treatment given above is intended for the control 

 of all the important apple troubles, such as scab, bitter-rot, blotch, 

 leaf -spot, codling moth, and canker worm. (B. P. I. B. 144.) 



Black Rot, Canker and Leaf Spot. The three diseases given 

 above have been found to be due to a single fungus, Sphseropsis ma- 

 lorum. The black rot of the apple is very common in New Hamp- 

 shire. It is dark brown or black in color and the affected tissue com- 

 paratively firm. It is thus readily distinguished from the soft rots. 

 It may start on any part of the fruit, but often begins at the blossom 

 and frequently follows insect stings. The disease is primarily a rot 

 of ripe fruit, but it may often be found as dark brown spots % to 1 /*} 

 inch in diameter several weeks before the apples are mature. These 

 spots may develop very slowly until about picking time, but after that 

 spread rapidly to involve the whole apple. As the rot develops, nu- 

 merous minute, black elevations may be seen on the apple. These 

 are the spore producing bodies of the fungus and are known as 

 pycnida. The rot does considerable damage in cellar storage, but is 

 especially common on the fruit left on the trees or ground. This 

 worthless fruit becomes a great source of infection the following 

 spring. Sprayings made at various times in the summer have had 

 little or no effect upon the number of spots of rot on the fruit at 

 picking time. The destruction of the affected fruit is apparently the 

 only efficient treatment for this form of the disease. All cankered 

 limbs should be cut out and burned. Proper treatment of wounds 

 and thorough spraying will decrease the number of cankers. Heavy 

 applications made when the trees are in a dormant condition are 

 probably especially efficacious. (N. H. E. S. B. 144.) 



Fruit Spot of Apples. This disease is of very common occur- 

 rence in New Hampshire and is found as far south as Maryland and 



