DISEASES OF CULTIVATED PLANTS 513 



To prevent scab, spray three times. Give the first application 

 just after the petals have fallen from the first blossoms and two 

 others inside the next six weeks. If the disease gains ground on 

 the young fruit, further spraying will be necessary. Shoots of sour 

 orange and diseased fruit should be removed and burned. 



Ammoniacal solution: Copper carbonate, 5 ounces; ammonia, 

 3 pints; water, 45 gallons. 



Dilute the ammonia with five gallons of water and add the 

 copper carbonate. Use a wooden or glass vessel. Stir thoroughly 

 until dissolved. This will give one ounce of copper carbonate to 

 each gallon. For use, add forty gallons of water, or, in smaller 

 quantities, one gallon of mixture to eight gallons of water. 



The following mixture of Bordeaux is recommended: Copper 

 sulphate, 4 pounds ; unslaked lime, 4 pounds ; water, 50 gallons. 



Dissolve the copper sulphate in twenty gallons of water. Slake 

 the lime in a small quantity of water; add water to make twenty 

 gallons. Mix the two solutions in a third vessel or in the barrel of 

 the spray pump, taking a pailful alternately from each of the 

 solutions. 



Die-Back. This disease takes its name from the fact that the 

 young twigs and branches of affected trees die back to a distance of 

 from two to eight inches, or even more, from their tips. 



No citrus trouble is more widely distributed throughout the 

 State than die-back. No locality is exempt from it, and no variety 

 free from its attack. Trees, young and old, suffer alike, and a few 

 trees have been found affecteo: which were still standing in the nurs- 

 ery rows. Very often little notice is taken of it, and it gradually 

 works its way, nipping off the new growth, and the trees, in con- 

 sequence, make very little progress. Years of work and much capi- 

 tal are often wasted in mistaken efforts to bring a grove into healthy 

 condition. 



The disease is easily recognized. The young twigs die back 

 several inches. Irregular, reddish-brown elevations, at first closed, 

 later cracked open and filled with a resinous substance make their 

 appearance on the small branches and twigs. These vary greatly in 

 length, height and shape. Often elevated pustules, filled with a 

 gummy substance, occur on the young growth. These seem, in some 

 cases at least, to develop into open ruptures. Adventitious buds are 

 frequently produced, and those which are not smothered by the 

 resinous exudation develop, thus giving rise to several branches from 

 a single node. Sometimes the only noticeable mark of the disorder 

 on a branch is the presence of a resinous knot in the axils of the 

 leaves where the buds should be. Slightly affected branches have 

 often a dark, greasy appearance. The small growth is usually twist- 

 ed and bent. On me fruit the disease is manifested by the presence 

 of dark brownish blotches and by cracking or splitting. Many fruits 

 drop off. As the disease advances the trees try in vain to throw out 

 new branches. Symptoms become more strongly marked, the tips of 

 the bare, distorted branches protrude above the dark-green foliage. 



