See under Peach.

Polygonum. Tar-Spot (Rhytisma Bistortae)

Black tar-like spots on leaves.


Burn affected leaves.

Pomegranate. Internal Rot (Sterigmatocystis Castanea)

Central cavity of fruit occupied by a black sporulating fungus.


None known.

Catalogue of Diseases, continued.

Pomelo. Wither-Tip (Colletotrichum Glaeosporioides)

Anthracnose cankers of stem, spots on leaves and flowers and general wilting of tips of branches.


Prune off affected parts and spray with bordeaux mixture.

Populus. Heart-Rot (Polyporus Sulphureus)

Red rot of the wood, which finally breaks up into cubes.


Surgery methods.

Potato. Early Blight (Alternaria Solani)

Circular spots, usually in July and final blighting of whole leaf.


Spray with bordeaux mixture, every ten days, beginning when plants are 6 to 8 inches high.

Late Blight And Potato-Rot (Phytophthora Infestans)

Quick-spreading watery appearing spots in leaves. Mildew on under side. Plants appear as scalded by hot water. Tubers rot in soil or soon after digging.


Spray with bordeaux mixture, 5-5-50, at least three applications and in wet seasons, six or more may be necessary. Use from forty to one hundred gallons per acre.

Scab (Oospora Scabies)

A scabby and pitted roughness of the tubers.


Keep lime and ashes off the land. Soak uncut seed tubers in a solution of formalin, one pint to thirty gallons of water for two hours. Avoid land that has grown scabby potatoes.

Potentilla. Leaf-Spot

See under Strawberry.

Primula. Rot (Botrytis Sp.)

Similar to rot of Paeonia, which see.


See under Plum.


See under Cherry, Plum and Peach.

Pseudotsuga. Blight (Sclerotinia Fuckeliana)

Gray mold of seedlings and younger shoots of older trees in moist situations.


Spray with bordeaux mixture.


See under Guava.


See under Apple and Pear. Quince.


See under Pear.

Rust (Gymnosporangium Globosum)

Orange rust of fruit.


Destroy red cedars in the neighborhood, also wild apples and hawthorns. Spray as for Apple Scab. Radish. White "Rust" or Mildew (Albugo candidus). - A whitish powdery growth on the leaves and petioles, often causing distortion.


Steam sterilize the soil before planting.


See under Cabbage.


See under Cabbage.

Ranunculus. Mildew (Plasmopara Pygmaea)

Downy mildew of leaves.


Spray with bordeaux mixture.

Raspberry. Anthracnose (Glaeosporium Venetum)

Circular or elliptical, gray scab-like spots on the canes.


Remove diseased canes as soon as fruit is picked. Avoid taking young plants from diseased plantings.


See under Blackberry.

Red, Or Orange Rust (Gymnoconia Interstitialis)

Dense red powdery growth on under side of leaves of black varieties and blackberries.


Dig up and destroy affected plants.


See under Dewberry. Same disease.

Retinospora. Gall (Gymnosporangium Sp.)

Swellings on limbs and twigs with red-brown pustules covering them.


Prune off affected parts and keep at a distance from species of Pomeae.

Rhamnus. Rust (Puccinia Coronata)

Irregular yellow blotches, with yellow pustules on under side of leaf. Also on fruit and flowers.


Keep at a distance from "rusted" cereals and other grasses.

Rheum. Soft-Rot

See under Carrot.

Rhododendron. Galls (Erobasidium Rhododendri)

Galls of the size of a pea or larger, at first pale green, then red and brownish covered with white bloom.


Leaves bearing galls should be removed and burned.

Rhubarb. Soft-Rot

See under Carrot.

Rhus. Canker And Twig Blight (Endothia Parasitica)

See under Chestnut. Causes death of twigs.


See under Currant and Gooseberry.

Richardia. Soft-Rot (Bacillus Aroideae)

Soft rotting of conns (bulbs) and leaves.


Change soil every three or four years. Reject corms which show the disease.

Robinia. Heart-Rot (Trametes Robiniophila And Fomes Rimosus)

Heart-wood converted into punk. Shelf-like bodies grow from wounds.


Surgery methods.

Rose. Mildew (Sphaerotheca Pannosa)

A white powdery mildew on new growth.


In greenhouses, keep steam-pipes painted with a paste of equal parts lime and sulfur mixed in water. Out-of-doors roses should be dusted with sulfur flower or sprayed with potassium sulfid, one ounce to three gallons of water.


Similar to Raspberry Anthracnose, which see.

Catalogue of Diseases, continued.


See under Raspberry.

Salix. Rust

Numerous species of the rust fungi produce red rust spots on the leaves.


Keep at a distance from species of conifers.

Heart-Rot (Trameles Suaveolens)

Enters through wounds.


Surgery methods.

Salsify. Mildew (Albugo Tragopogonis)

Distortion and white blisters on host.


Eradicate affected plants and grow on new soil apart from wild and cultivated species of the Composiatae.

Sambucus. Cankers

See under Lonicera.

Sarracenia. Blight

See under Orchids.

Saxifraga. Rust (Puccinia Pazschkei And P. Saxifrage)

Dark brown concentric circles of rust pustules on upper surface of the leaves.


Burn affected leaves.