1916] DISEASES OF PLANTS. 549 



1916 is given for the control of scab and mildew, or of scab alone, in the 

 Hood River Valley. This includes the use of lirae-suli)hur as a delayed dor- 

 mant spray, followed by a more dilute lime-sulphur just as the petals are 

 beginning to open, with a third spraying immediately after the petals have 

 fallen. In the third spraying the authors recommend the use of atomic 

 sulplmr if the weather is clear and warm, or lime-sulphur with atomic sulphur 

 added if the weather is cool and rainy. Two other applications are recom- 

 mended, depending upon conditions in the orchards. In the first application, 

 for the control of purple aphis uicotin may be used, and in the third and fifth 

 lead arsenate may be added to the fungicide as a protection against codling 

 moth injury. 



Six years of experimental apple spraying at Highmoor Farm, W. J. Morsk 

 {Maine Sta. Bui. 2J,d (1916), pp. 81-96).~In previous publications (E. S. R.. 33, 

 p. 648) accounts have been given of the results obtained from spraying experi- 

 ments for control of apple scab. In the present bulletin an attempt is made 

 to present p. general summary of the more important results obtained. The 

 I)rimary object of the experiments was to determine an eflicient and economical 

 control of apple scab with a minimum amount of injury to fruit and foliage, 

 as applied under Maine conditions. With the different fungicides, arsenate of 

 lead was added as an insecticide at the rate of 2 lbs. of paste or 1 lb. of 

 powder to 50 gal. of solution. 



A comparison was made of 3 : 3 : 50 Bordeaux mixture and a standard 

 dilution of lime-sulphur which was equivalent to a 1 to 40 dilution of a 33° 

 Baume concentrate. Bordeaux mixture, while efficient in scab control, nearly 

 always caused serious leaf injury, and sometimes resulted in a considerable 

 russeting of the fruit. Lime-sulphur of standard dilution gave little leaf injury, 

 but was somewhat less efficient in controlling the disease. 



The effect of different dilutions of lime-sulphur was investigated, antl a 

 spray containing 25 per cent less of the concentrate than the standard dilution 

 resulted in the appearance of more scab than where the standard dilution was 

 used. A comparison was made between the standard dilution and one 20 

 per cent stronger for four successive seasons, and it appears that on the Ben 

 Davis apple a solution of lime-sulphur at least 20 per cent stronger than the 

 standard dilution can be used with comparative safety. 



The importance of a first application at the time of the blossoming period 

 was also tested, and while some increase was given during certain seasons, 

 yet the general results indicated that failure to spray at this time did not 

 greatly reduce the efficiency of subsequent applications. 



Arsenate of lead used alone in the progress of these experiments was found 

 to have considerable value as a fungicide. In some instances trees receiving 

 arsenate of lead gave almost as good control as where the insecticide was used 

 in combination with the fungicide. 



Notes are given on the effect of strong fungicides used as a first application 

 followed by arsenate of lead alone, and the effect of dormant sprays for insects 

 used in combination with the regular summer sprays. A comparison was made 

 between self-boiled lime-sulphur and other forms of this fungicide which 

 indicates that it is less efficient than the dilutions made from certain com- 

 mercial brands of lime-sulphur concentrate. A trial was made of copper- 

 lime-sulphur which indicated that, so far as scab control is concerned, it is 

 about as efficient as the same dilution of lime-sulphur, but the presence of 

 copper resulted in considerable foliage injury. Extra fine sulphur flour was 

 found to possess considerable fungicidal value. 



Comparative tests were made of a number of proprietary spraying compounds. 

 Sulfocide, while efficient in scab control, caused a considerable amount of 



