26 



any one part, or perhaps only for the fraction of a second. Go over 

 the whole plantation in this manner. After completing one round 

 repeat the operation at once, making sure that the first spray is dry 

 before the application of the second. This need not occupy more time 

 than would be given to the spraying in the ordinary way. Simply 

 decide how much time is to be given to the job, and devote to the 

 first dose one half of the time, and to the second dose the other half. 

 In the end no more time will have been consumed, and not much 

 more labour and no more material, but the result, I can assure the 

 reader, will be a decided improvement. The poison will be found to be 

 placed on the leaves in smaller and more numerous patches, and in 

 consequence it will be much more effective. 



Varying Resistance. The fact that the numerous varieties display 

 a varying susceptibility to the attacks of Gloeosporium suggests an 

 explanation of the varying results of spraying with fungicides. 

 Different experimenters, after carefully-conducted experiments, have 

 secured varying success in the application of fungicides for the pre- 

 vention of this disease. Among the causes for these varying results 

 we must reckon the varying susceptibility of varieties. A very 

 susceptible variety will naturally receive less benefit from a given 

 series of applications of, say, Bordeaux mixture, than a less susceptible 

 variety. It is noticeable that little attention has been given to this 

 point in reports on experiments for the prevention of ripe rots. 

 Often no note is taken of the variety sprayed, and never, so far as 

 my reading goes, has allowance been made for varying degrees of 

 susceptibility. 



According to my experience, it is the early and non-keeping varieties 

 of fruit that are most susceptible to the attacks of G-loeosporium, and 

 of these two qualities, which, of course, often go together, and are so 

 intimately associated that it is impossible to separate them, it is the 

 fugitive quality that seems to exert the most important influence. If, 

 for instance, an early sort is also a fair keeper, it will be found that it 

 is at all times more resistant to the rot than the equally early sorts 

 that do not keep so well. Apples with a russet skin are usually 

 resistant to Gloeosporium, and the summer varieties with russet skin 

 are examples of early, yet somewhat resistant, varieties. 



Birds and insects are connected with the rot fungi in an indirect 

 way. The peckings of birds, and the bites, stings, and scratches of 

 insects are, of course, to be guarded against if immunity from fungi 

 is desired. Insects, apart from the direct injury they do, are a 

 source of loss in that they open up the road for the ripe-rot fungi. 

 There seems to me to be some ground for believing that the ^aphides 

 and, perhaps, the scale insects disinfect their punctures. At any rate 

 it is difficult on any other ground to account for the fact that their 

 punctures do so little harm in proportion to their number. But this 

 is at present only a hypothesis. With many other insects the case 

 lies otherwise, for it can be shown that various rots follow on their 

 attacks. 



I have often observed, in connection with my experiments, that no 

 sooner do well-developed pustules of the rot fungi appear, than I 



