18 



APPLE BLOTCH IN SOUTHERN ORCHARDS. 



that but few infections took place during the remainder of the season. 

 The last two applications, made on June 15 and July 5, were there- 

 fore of little value in the control of the disease ; but during a season 

 of ordinary rainfall infections take place throughout the season, mak- 

 ing late spraying necessary for proper protection, as was demon- 

 strated in the previous year's work. 



The most striking feature of this experiment, as shown in the table, 

 is the effect of the first application, made thirty days after the petals 

 fell. The disease was successfully controlled in all the plots which 

 received this application, while more than half the crop of the plots 

 on which it was omitted was affected. This will be clearly seen by 

 comparing the results from Plots 2 and 5, both of which received 

 three applications, the only difference being that the treatment of the 

 latter was not begun until three weeks after that of the former. The 

 crop of Plot 2 shows only 3.7 per cent of diseased fruit, while 68.5 

 per cent of that on Plot 5 was affected. Plots 3 and 6 may be simi- 

 larly compared. The crop of the check trees was almost wholly de- 

 stroyed by the disease, 90.3 per cent of the fruit being affected. This, 

 when compared with Plots 1 and 2, in which less than 5 per cent of 

 the crop was diseased, shows very strikingly the good results from 

 timely applications of Bordeaux mixture. (PI. V, figs. 1 and 2.) 



This experiment was practically duplicated on a block of Limber- 

 twigs in the same orchard, and the results are given in Table II, 

 which follows. 



Table II. — Results of experiments for the control of apple blotch on Limber- 

 twig trees, Bentonville, Ariz., 1907. 



Plot numbers (2 trees of each 

 plot.) 



Treatment with Bordeaux mixture 

 (5-5-50 formula). 



Fruit picked October 5 to 10. 



Sound 

 fruit. 



Blotched fruit. 



Apr. 27 



Apr. 27 



Apr. 27 



Apr. 27 



6, check (4 trees) , no treatment. 



May 22 

 May 22 

 May 22 



May 22 



June 15 

 June 15 



June 15 

 June 15 



July 5 



July 5 

 July 5 



Number. 

 •4,233 

 7,170 

 4,256 

 6,824 

 3,115 

 3,158 



Number. 



305 

 646 



6, 515 



17,688 



Per cent. 

 7.8 

 5.1 

 6.7 

 8.6 

 67.7 

 84.9 



The results on the Limbertwig trees, as shown in this table, were 

 about the same as those obtained on the trees of the Ben Davis variety. 

 Again the importance of the first application, April 27, is emphasized, 

 the disease being controlled on all plots receiving this treatment. 

 Plot 2, which received three applications, beginning on April 27, 

 had only 5.1 per cent of the crop affected, while Plot 5, which re- 

 ceived the same number of treatments, though beginning three weeks 



144 



