Control. - Reject all diseased tubers for seed. Practice a rotation in which potatoes are not grown on the soil for at least two years.

Scab (Oospora scabies). - A scabby and pitted roughness of potato tubers. Lime, ashes or manure added to the soil increases the amount of scab by favoring the growth of the fungus. It has become one of the serious diseases of the potato.

Control. - Do not plant on land which has grown scabby potatoes. Plant clean seed. If only scabby seed is at hand, soak the uncut tubers in a solution of formalin, 1 pint in 30 gallons of water, for two hours. Drain, cut, and plant in clean soil. Use the formalin solution over and over. The same fungus also attacks beets. Pumpkin. — See under Muskmelon (p. 274).

Quince. Black-rot (Sphaeropsis malorum). —A trouble which usually appears at the blossom end of young quince fruits, causing them to become black and hard, with a dry rot of the tissue. The same disease occurs on apples, which see.

Blight. — See under Pear Blight (p. 277).

Leaf- and Fruit-spot. - See Pear-Leaf Blight, which is the same disease.

Rust. - The organism causing this disease is of the same habit and nature as that causing apple rust.

Control. — As for Apple Rust (p. 264). Radish. White rust or Mildew (Albugo candidus). — A whitish powdery growth on the leaves and petioles, often causing distortion.

Control. - Steam-sterilize the soil before planting. Club-root. - See under Cabbage (p. 266). Raspberry. Anthracnose (Glaeosporium venetum). — Circular or elliptical, gray scab-like spots on the canes.

Control. - Avoid taking young plants from diseased plantations. Remove all diseased canes as soon as the fruit is picked. Practice frequent rotation. Crown-gall or Root-call (Bacterium tumefaciens). - Tumerous outgrowths on the roots, especially on red varieties. It is contagious and destructive.

Control. - Never set plants which have galls on the roots. Avoid setting on infested land. See under Peach (p. 276). Red or Orange rust (Gymnoconia interstitialis). - A dense red powdery growth on the under side of the leaves of black varieties and of blackberries. The fungus hibernates in the roots. Control. - Dig up and destroy infected plants. Rice. Blast, Blight or Rotten-neck (Piricularia oryzae). - An extensive paling and drying of leaf and stem, and a partial failure of the heads to fill.

Control. — The selection of early maturing varieties is advisable. Burn stubble and trash left in the fields. Rose. Black leaf-spot (Actinonema rosae). - Attacks the full-grown leaves, first appearing as small black spots, but later covering nearly or quite the whole surface with blotches. The spots have frayed edges.

Control. - Spray with ammoniacal copper carbonate, beginning with the first appearance of the spots and continuing at intervals of one week until under subjection. Mildew (Sphaerotheca pannosa). - A white powdery mildew on the new growth.

Control. - For greenhouse roses keep the steam pipes painted with a paste made of equal parts lime and sulfur mixed with water. Out-of-door roses should be dusted with sulfur flour or sprayed with potassium sulfid, 1 ounce to 3 gallons of water. Spinach.- There are numerous fungous diseases of this crop, but a practical method of control has not been developed. The best that can be done is to rotate crops.

Strawberry. Leaf-spot or leaf-blight (Mycosphaerella fragarice). -Small purple or red spots appearing on the leaves. They increase in size and make the leaf appear blotched. The fungus passes the winter in the old diseased leaves that fall to the ground.

Control. - In setting new plantations remove all diseased leaves from the plants before they are taken to the field. Soon after growth begins, spray the plants with bordeaux mixture, 4-4-50. Make three or four additional sprayings during the season. The following spring spray just before blossoming, and again in ten to fourteen days. If the bed is to be fruited again, mow the plants and burn over the bed as soon as the crop is off. Mildew (Sphaerotheca castagnei). - A whitish cobweb-like mildew on fruit and leaves, causing the latter to curl.