32 NEBRASKA STATE HORTICULTURAL SOCIETY. 



ID the interior of each fruit there is at maturity a single spore-sac 

 (Fig. 6, B) containing eight roundish spores. The thick wall of the 

 fruit, and the thickish wall of the spore-sac, form a sufficient protec- 

 tion to the spores, which are thus enabled to pass the winter un- 

 harmed. The next spring they germinate in the masses of decaying 

 leaves, and thus easily infect the lower leaves of seedling trees, from 

 which they readily pass to older trees. 



Burning the leaves in the fall or early winter will reduce the lia- 

 bility to the propagation of the disease next year. 



Spraying the trees several times in the early part of the year, as 

 soon as the disease appears, with a watery solution of the arnmoniacal 

 carbonate of copper* will kill the fungus. 



Scab. The disease of the leaves here referred to is known also as 

 "leaf blight," a term of doubtful propriety, as it is liable to lead to 

 confusion with the true blight (see below). It is produced by the 

 same minute fungus which is the cause of the scab on the fruit; in 

 fact we have here a case of the same disease attacking both leaves and 

 fruit. The leaves affected by scab become yellowish, and on the un- 

 der surface show a more or less abundant growth of blackish, jointed, 

 branching threads (Fig. 7). Spraying with ammoniacal carbonate of 

 copper is recommended for this form of the scab. 



Rust. This disease is abundant in some parts of the east, but so 

 far as I am aware it has not yet appeared in Nebraska. It will 

 doubtless reach our orchards in time, and so may properly be noticed 

 here. It consists of bright yellow patches upon slightly thickened 

 portions of the leaf surface. On close examination with a hand lens 

 these patches are seen to consist of yellow cup-shaped fruits of a fun- 

 gus which grows in the interior of the leaf, finally rupturing the skin 

 to bring the spores to the surface. The spores germinate, not on ap- 

 ple leaves as might be supposed, but upon the red cedar, producing 

 the kind of rust on it known as " cedar apples," and the spores from 

 the latter infect the apple leaves again. 



When abundant it is a most serious disease. It is noticed here in 

 order to forewarn our orchardists. On its first appearance the trees 



* Ammoniacal carbonate of copper is prepared as follows: 



Carbonate of copper 5 ounces. 



Ammonia (liquid) 3 pints. 



Mix thoroughly until the copper is dissolved. 



Add water 45 gallons. 



