8 



e.rs in the same section and in close proximity to one another often prac- 

 tice widel}^ different methods in growing this crop, and 3'et the results 

 obtained are practicall}^ the same. A novice in violet growing may 

 have little or no difficulty the first few years in growing good flowers. 

 After this, however, his troubles usually begin and failure more often 

 than success crowns his efforts. Unless he is possessed of peculiar 

 abilities and a determination to succeed a few years of reverses are suf- 

 ficient to cause him to abandon the culture of violets and turn his 

 attention to some other industry where the chances of success are at 

 least equal to those of failure. 



GENERAL APPEARANCE OF THE DISEASE. 



Spot disease of the violet {AUernaria molce) attacks the plants at any 

 stage of their growth from the small unrooted cutting in the cutting 

 bed to the mature plant in full flower. (See Pis. II, III, and IV.) 

 Plants that are making a vigorous, rapid, but soft or succulent growth 

 are most subject to the disease. The disease may occur on any por- 

 tion of the plant above ground, but causes the greatest amoimt of loss 

 when present upon the foliage. Its first appearance upon the leaves 

 is characterized by small, definite, usualh' circular, greenish or yel- 

 lowish white spots, resembling very much the ))ite or sting of an insect. 

 They var}' in size from dots scarcely perceptible to the unaided 63^6 to 

 spots a thirty- second of an inch or more in diameter. The light- 

 colored central portion or point of infection is surrounded by a narrow 

 ring of discolored tissue, usually black or very dark brown at first, but 

 changing to a lighter shade as the spots grow older. (Pis. II, III, 

 IV.) As the spot develops the central portion remains unchanged in 

 appearance, while the tissues immediately surrounding it, either to one 

 side or more frequently in a circle, become diseased by the ramify- 

 ing growth of the mycelium of the fungus through this portion of the 

 leaf. This usuall}- takes place within a few hours after infection. 

 The freshly diseased portion of the leaf at first presents a water- 

 logged appearance, frequently being semi-transparent, and is lighter 

 in color than the adjacent healthy tissue. The diseased portion around 

 the central point of infection in a few days fades or bleaches to a yel- 

 lowish or grayish white, sometimes to a pure white, the time depend- 

 ing somewhat upon the conditions of the weather. The development 

 of the disease may stop at this point and the plants apparentlj^ entirely 

 recover from its effects; in which event the diseased portions of the 

 leaves after a few days separate from the healthy tissue and fall out, 

 leaving the leaves full of holes. More frequently, however, the 

 disease continues to develop in the parts of the leaf adjoining or sur- 

 rounding those alreadj^ diseased. These freshly diseased areas in turn 

 pass through the same changes as the parts previously attacked. 

 Unless checked by some means the disease continues to spread in this 



