APPLE RUST 413 



The best method, therefore, to reduce the attacks of this disease 

 is to practice rotation of crops and to prevent masses of the smut 

 from being scattered in the manure. Smutted ears should never 

 be taken to the feed lot or barnyard. 



Grain Rust. Leaves and stems of small grains are often badly 

 affected with two diseases, known as leaf rust and stem rust. The 

 former is brown, and the latter appears in black spots on both 

 leaves and stems. Stem rust is less common but more injurious 

 when present. Weather conditions seem to greatly influence the 

 growth of these diseases. These are not within the control of the 

 farmer. Well drained soil should always be used in regions where 

 rust is prevalent. Small grains grown in southern latitudes are 

 more subject to rust than in the North. 



Apple Scab. This disease attacks both the leaves and the fruit, 

 on which brownish, scab-like spots are formed, and the .size of the 

 fruit is often much diminished because of the disease. The market 

 value of the fruit is much reduced^ and the grower often loses many 

 dollars by not preventing the disease. The rusty, irregular blotches 

 often deform the fruit, and sometimes pits are formed. 



The two chief spray materials used as prevention of this 

 disease are lime-sulfur, applied when the trees are in their winter 

 condition, or Bordeaux mixture, the strength of which is varied 

 to suit the condition of the trees. With either of these materials 

 Paris green or arsenate of lead may be mixed to aid in the control 

 of codling-moth and canker worm. (See Chapter XXX for pro- 

 portions.) 



The first spraying should be done when the trees are dormant, 

 and if lime-sulfur is used, the San Jose scale will be largely con- 

 trolled by this early application. The arsenic need not be used 

 for this first spraying. The second application is made at the 

 time the petals fall. At this time poison is very essential. A 

 third spraying is given about two or three weeks later. At this 

 time Bordeaux is somewhat preferable to the lime-sulfur. (See 

 Chapter XXVIII for insects affecting the apple orchard.) 



Apple Rust. This disease is also known by the name "cedar 

 apple." The disease is a fungous growth which appears in two 

 forms, one attacking the apple, forming a so-called rust growth 

 on- the leaves, young twigs and green fruit ; the other form growing 

 on red cedar trees, and appearing in the form of brown or yellow 

 swellings the size of small apples which when dry are much shriv- 

 elled and may have a purplish color. As this alternate growth of 



