PROTECTING PLANTS 213 



Rose diseases. — Black leaf-spot is one of the commonest diseases 

 of the rose. It causes the leaves to fall prematurely. Spray with 

 bordeaux, 5-5-50, beginning as soon as the first spots appear on the 

 leaves. Two or three applications at intervals of ten days will very 

 largely control the disease. Ammoniacal copper carbonate may be 

 used on roses grown under glass. Apply once a week until disease is 

 under control. 



For mildew on greenhouse roses, keep the steam pipes painted with 

 a paste made of equal parts lime and sulfur mixed up with water. 

 The mildew is a surface-feeding fungus and is killed by the fumes of 

 the sulfur. Outdoor roses that become infested with the mildew may 

 be dusted with sulfur, or sprayed with a solution of potassium sulfide, 

 1 oz. to 3 gal. water. Spray or dust with the sulfur two or three 

 times at intervals of a week or ten days. 



Strawberry leaf-spot. — The most common and serious fungous 

 disease of the strawberry; also called rust and leaf-blight. The leaves 

 show spots which at first are of a deep purple color, but later enlarge 

 and the center becomes gray or nearly white. The fungus passes the 

 winter in the old diseased leaves that fall to the ground. In setting 

 new plantations, remove all diseased leaves from the plants before they 

 are taken to the field. Soon after growth begins, spray the newly set 

 plants with bordeaux, 5-5-50. Make three or four additional spray- 

 ings during the season. The following spring, spray just before blos- 

 soming and again 10 to 14 days later. If the bed is to be fruited a 

 second time, mow the plants and burn over the beds as soon as the 

 fruit is gathered. Plant resistant varieties. 



Tomato leaf-spot. — The distinguishing character of this disease is that 

 it begins on the lower leaves and works towards the top, killing the foliage 

 as it goes. It is controlled with difficulty because it is carried over 

 winter in the diseased leaves and tops that fall to the ground. When 

 setting out plants, pinch off all the lower leaves that touch the ground ; 

 also any leaves that show suspicious-looking dead-spots. The trouble 

 often starts in the seed-bed. Spray plants very thoroughly with 

 bordeaux, 5-5-50, beginning as soon as the plants are set out. Stake 

 and tie up for greater convenience in spraying. Spray under side of 

 the leaves. Spray ever^ week or ten days. 



