No. 6. DEPARTMENT OF AGRICULTURE. 451 



applied two to three weeks after the petals fall and the second a 

 month later. The advantages of two treatments consist of a more 

 timely covering of the earl}- foliage and the later at which the 

 second is made gives an opportunity to cover the later formed leaves. 

 Leaf blight is so easy to prevent that usually the treatment for scab, 

 especially when Kos. 1 and 2 are supported by Xos. 4 and o, is amply 

 sufficient to prevent it. In the same way the treatment for apple bit- 

 ter rot when begun early enough suffices for the treatment of leaf 

 blight. I wish to emphasize the importance of a study on the part 

 of the orchardist of his varieties and their relative susceptibility to 

 disease. For instance the Winesap and its seedlings, Stayman 

 Winesap, Mammoth, Black Twig, and Paragon, are very suscepti- 

 ble to scab. Where scab occurs at all they are likely to be attack- 

 ed. Probably in this county it will pay, in fact it will be necessary. 

 to succeed commercially with these varieties, to spray the Winesaps 

 with at least Nos. 1 and 2, and probably with Xos. 1, 2 and 4 for apple 

 scab. On the other hand Winesaps have so little bitter rot, even in 

 the worst districts, that it scarcely ever pays to treat them for this 

 disease. Again, York Imperials have so little scab that is probably 

 would not pay to give them even the abbreviated scab treatment. 

 It is doubtful whether it would pay to spray York Im}>erials for 

 scab at all unless you add an arsenical to treatment No. 2 when the 

 petals fall, giving the combined codling moth and scab treatment. 

 Three or four weeks later, at the time of No. 4 or 5, it can be given 

 the combined -codling moth and apple leaf blight treatment in the 

 shape of a single spraying. With the Ben Davis variety, I am in 

 doubt. Some years it scabs early and badly enough to be worth 

 while to spray. At other times, it scabs scarcely any. It is, how- 

 ever, very susceptible to the leaf blight fungus and is nearly always 

 benefitted by a Bordeaux mixture treatment after the leaves are 

 fully out. This, of course, can be worked in at a time when arsen- 

 ical spraying is necessary for codling moth. It is necessary, there- 

 fore, to know the full set of diseases of each variety, and in fact, each 

 variety in each locality of our great country, and to establish the 

 most economical treatment for that variety in a particular locality. 

 lu past years there has been a great deal of effort put forth on the 

 part of pathologists and investigators to persjuade the orchardists 

 to spray with fungicides and insecticides in combating these pests; 

 but no greater mistake can be made than to recommend wholesale 

 and promiscuous spraying for the whole line of fungus and in- 

 sect pests on all varieties in all localities. 



What the orchardists want is to get the maximum results in 

 preventing these troubles with the minimum expenditure of time 

 and money. He shouM make a special study, therefore, of each 

 commercial variety of fruit which he grows and its diseases and 

 insect pests. If help is needed in determining the nature of these 

 troubles, specimens can be sent by mail to the De]nirtment of Agri- 

 culture, at Washington, D. C, or to the neare«t_Exji(Minient Station 

 and thus identified. ^\^ry frequently a State official or a local in- 

 spector can be called in who knows the disease and its cause and the 

 exact treatment in the given locality. The particular diseases, there- 

 fore, attacking each variety, time or their appearance and their 



