490 



ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 



Fig. 1. Sooty Blotch of Apple. 



latter numerous minute specks. They 

 give the apple a sooty appearance that 

 depreciates the market value. The fungus 

 growth is entirely on the surface ot the 

 fruit, and hence the disease is especially 

 dependent upon the moist weather for 

 development. 



Treatment 

 The disease is readily controlled by 

 spraying. Thorough pruning is impor- 

 tant, and if light and air have free access 

 to the fruit the disease usually gives 

 little trouble. 



Fig. 2. Sooty Blotch and Fly Speck Fungus. 



Sooty Mould 



Capnoditim sp. 



Black sooty fungus sometimes found 

 growing upon branches and twigs. Fre- 

 quently caused by the deposits of "honey 

 dew" from aphids, which is a favorable 

 medium for the growth of the fungus. 

 Not serious. 



Spray Injnry 



Injury from Bordeaux mixture is of 

 quite common occurrence. On the leaves 



it appears first as purplish brown spots 

 of various shapes and sizes. They are 

 usually smaller, irregular in shape and 

 thickly distributed on the affected foliage. 

 Soon after the appearance of these spots 

 the leaves may begin to turn yellow. 

 Leaves so affected soon fall, and in serious 

 cases the trees may be almost entirely 

 defoliated. Such extreme cases, how- 

 ever, have been very rare. 



On the fruit the injury appears first 

 as small, black or brown specks scat- 

 tered thickly over the apple. Later in 

 the season the skin may become corky 

 and russeted. In serious cases the ap- 

 ple may be much roughened and deform- 

 ed, and large, deeply-sunken scars de- 

 velop. The slightly affected fruit may 

 almost entirely outgrow its injuries by 

 picking time, but when the injury is very 

 great the fruit may drop before maturity, 

 and in any case is of little commercial 

 value. 



The most serious injuries have been ob- 

 tained from the early sprayings. This 

 may be largely due to the fact that show- 

 ers are common at that time of year. It 

 is a well-known fact that when an ap- 

 plication of Bordeaux is followed by rain 

 within the next few days it is likely to 

 produce injury. Records from a large 

 number ot cases of Bordeaux injury would 

 indicate that damage seldom, if ever, oc- 

 curs in properly sprayed orchards except 

 under the above mentioned conditions. 



The injury done by Bordeaux has not 

 been great enough to offset the good ac- 

 complished, and various commercial grow- 

 ers have annually obtained large profits 

 from its use, yet the condition has been 

 serious enough to make strong demands 

 for a solution of the difficulties. The mat- 

 ter has been taken up at various experi- 

 ment stations. Including those of New 

 York,' Illinois' and New Hampshire, but 

 a complete solution of the problem has 

 not been found. 



Much trouble may arise from the use 

 of improper mixtures and from unsatis- 



' ITedi-ick. N. P. Bordeaux Injury. N. T. 

 Agricultural Experiment Station Bulletin 287. 

 1907. 



' Crandall. C. R. Bordeaux Mixture. Il- 

 linois Agricultural Experiment Station Bulle- 

 tin 135. 1909. 



