VIOLET 



The Violet frames, which are either stationary or 

 movable, are made of rough boards, and are about 5 ft. 

 10 in. wide, of any desired length, from 12 to 15 in. 

 high in front and 18 to 20 in. high at the back. The 

 best location for the frames is a piece of ground slop- 

 ing to the south, with a wind-break of some kind to the 

 north and northwest to protect them during 

 the winter from the cold winds. 



Marketing is one of the most important fac- 

 tors connected with commercial Violet-growing 

 and is seldom understood in all its details. 

 The grower should be thoroughly familiar 

 with the many needs and requirements of the 

 market and be able to supply these demands, 

 for upon his ability to do this depends largely 

 his success or failure from a financial stand- 

 point. Violets are prized chiefly for their deli- 

 cate perfume, and as this diminishes in proper 

 tion to the length of time they are picked, the 

 best market, other things being equal, is the 

 one which requires the least possible delay be- 

 tween picking the flowers and placing them in 

 the hands of the customer. 



The crop may be disposed of at retail or 

 wholesale or through a commission merchant. 

 Each method has its advantages and disadvan- 

 tages, and in deciding which one to adopt '!., 

 grower must be guided by existing conditions. 

 He must in any event have a thorough knowl- 

 edge of the requirements or the market as re- 

 gards quality '>f the flowers, size, shape and 

 arrangement of the bunch, and should at all 

 times exercise the utmost! care in picking, packing and 

 shipping, so that the flowers may reach the customer 

 in the best and most attractive condition. The kind 

 of bunch varies from year to year, and each large city 

 is likely to have its own style. The various styles are 

 wonderfully exact in their requirements and great skill 

 is required to bunch the flowers properly. 



Diseases. The cultivated Violets are subject to a 



VIOLET 



1945 



pox, is the most widespread and destructive known in 

 America. It attacks principally the foliar, normally pro- 

 ducing definite circular whitish spot*, frequently" with 

 concentric rinirs, of adarker shade. very often with'a light 

 central portion resembling the bite or Bttag of an insect. 

 Cercospora i-i,,l,i . I'hi/llosticta viola, beptoriu 



2691. Swanley (X 1). 



number of diseases, each of which is characterized by 

 ne or more distinct symptoms. The principal diseases 

 are as follows, their destructiveness being in fte order 

 in which they are discussed : 



Spot disease (AUernaria tuote).-This disease, 

 also called the disease, leaf-spot, leaf-mst and small- 



0692. House of VioleU. 



etc., produce spots very similar in outline and appear- 

 ance to those caused by AUernaria viola, but only 

 under conditions peculiarly favorable to these fungi do 

 they cause any serious loss. For recent information on 

 this disease, see "Spot Disease of the Violet," Bull. 23, 

 Div. Veg. Physiology and Pathology-, U. S. Dept. Agric. 



Root rot (Thielavia basicola.). This disease is very 

 troublesome and destructive in some localities espe- 

 cially to young plants that are transplanted during hot, 

 dry weather. It causes the browning or blackening of 

 the parts attacked and the final death of the plant. 



Wet rot (Botrytis up.). This fungus attacks leaves, 

 detioles, flower-stalks and flowers, causing a wet or soft 

 rot. It is sometimes very destructive, especially with 

 large plants growing in a damp, stagnant atmosphere, 

 where there is insufficient ventilation and light. 



Leaf-fading or yellowing. This is induced by a va- 

 riety of conditions, but as yet little that is definite has 

 been ascertained regarding its cause. 



Remedies. -It is difficult to exterminate any of the 

 diseases named after they once gain a foothold. How- 

 ever, they can be held in check and often entirely pre- 

 vented by selecting and propagating exclusively from 

 strong, vigorous, disease-resistant plants, and by keep- 

 ing them in the best possible growing condition. Care- 

 ful attention must be given to watering, cultivation and 

 ventilation, and the dead and dying leaves and all run- 

 ners should be destroyed as fast as they appear. 



A n i m a I Enemies. Although Violets are attacked by 

 a number of insects and other animal enemies, only a 

 few do sufficient injury towarrant discussion here. 



Aphides (Aphis ? sp. and Rhopalosiphum violtr). 

 These pests are generally known as the green and the 

 black aphis or the green and the black fly. They cause 

 the young, growing parts to curl and twist, resulting 

 in a stunted,' ill-formed plant. They work their \vy 

 into the young, unopened flower-buds, and, thrusting 

 their bills through the overlapping petals, feed on the 

 juice. Each puncture produces a greenish white blotch 

 on the petal and the flower becomes dwarfed, distorted 

 and worthless for market. Aphides can be easily con- 

 trolled by fumigating with hydrocyanic acid gas, and 

 this is the method of treatment which should come into 

 general use. To each cubic foot of space in the house 

 or frame use .15 gram of 98 per cent cyanide of potash 

 for double varieties and .10 gram for single varieties. 

 Handle the cyanide and gas with utmost caiv , as both 

 are very poisonous. Divide the total amount of cyanide 

 into as'titany e.|iial parts as there are ji.rs used, which 

 latter should be one for every 50 to 7r> lineal feet of a 

 house 12 to 18 feet wide. Put each part into a 2-pound 



