Juniperus. Cedar Apples (Gymnosporangium Spp.)

Large or small red and woody growth at tips of branches. Gelatinous in wet weather.


Prune off affected parts. Keep apples, pears, and hawthorns at a distance.

Kale. Black-Rot

See under Cabbage. Kohlrabi.


See under Cabbage.

Laburnum. Leaf-Spot (Peronospora Cystisi)

Leaves become brown-spotted. Seedlings killed.


Spray with bordeaux mixture.

Contagious Chlorosis

See under Abutilon.

Larix. Canker (Dasyscypha Willkomii)

Canker of trunk and branches, usually around base of trunk.


Eradicate diseased parts, using tree surgery methods.

Laurus. Witches' Broom (Exobasidium Lauri)

Branched out growths, antler-like, 2 or 3 feet in length, springing from the leaves.


Prune off affected parts.

Lemon. Brown-Rot (Pythiacystis Citrophthora)

White mold on surface of fruit.


Not destructive in orchard. Add copper sulfate to water when washing lemons to prevent infection of healthy ones.


Not well understood. Probably controllable by spraying.

Lespedeza. Mildew (Microsphaera Diffusa)

Powdery mildew of leaves.


Dust with sulfur.

Lettuce. Drop, Or Rot (Sclerotinia Libertiana)

Base of stems or leaves rots off, allowing leaves to drop.


Sterilize soil with steam before planting.


See under Cineraria.

Ligustrum. Anthracnose (Gloeosporium Cingulatum)

Affected areas light brown either oblong on one side of the stem or completely girdling it.


Destroy by burning affected plants.

Lilium. Leaf-Spot (Botrytis Sp.)

Orange-brown or buff blotches on leaves, stem and flowers of L. candidum. May be same as Tulipa Mold, which see.


Eradicate diseased plants.

Lily-Of-The-Valley. Stem-Rot

See under Paeonia.

Liriodendron. Twig Blight (Myxosporium Longisporium)

Killing twigs.


Prune off diseased twigs.

Lobelia. Canker (Phoma Devastatrix)

Portions of the stems covered with minute black dots.


Remove diseased plants. They never bloom.

Lonicera. Canker (Nectria Cinnabarina)

Rough canker on limbs covered with flesh-colored or red bodies.


Prune off or cut out all affected parts and cover wounds with tar.


See under Pea.

Lychnis. Smut (Ustilago Violacea)

Pollen-sacs filled with black dust which escapes and discolors the flower.


Destroy the affected plants and use Dew soil.


See under Tomato.

Magnolia. Leaf-Spot

See under Grapefruit.

Malva. Rust

See under Hollyhock. Same disease.

Catalogue of Diseases, continued.

Mangifera. Black Blight (Dimerosporium Mangiferum)

Intense black velvety patches on both surfaces of the leaves.


Spray with any good spray mixture. Matthiola.


See under Cabbage.

Mentha. Rust (Puccinia Menthae)

A most destructive rust disease.


None given.

Mignonette. Leaf-Spot (Cercospora Resedae)

First reddish discoloration of leaves. Later small depressed spots with brownish or yellowish margin.


Spraying with bordeaux mixture gives good results.

Morus. Leaf-Spot (Cercospora Moricola)

Not serious.

Leaf-Blight (Pseudomonas Mori)

Wilting and death of leaves. Cankers girdle the twigs.


Prune off diseased parts and burn. Muscari.

Smut ( Urocystis Colchici)

Long black powdery streaks on leaves.


Destroy affected plants by burning. Use new soil.

Mushroom. Mold (Mycogone Perniciosa)

Mushrooms develop abnormally as monstrous soft growths. These develop into a moldy mass and putrify.


Affected beds should be thoroughly cleaned and sprayed with copper sulfate, one pound to fifty gallons of water.

Muskmelon. Downy Mildew. - See Under Cucumber. Wilt

See under Cucurbita.

Narcissus. Leaf-Spot (Ramularia Narcissi)

Spots on leaves and stem.


Burn diseased parts and spray with bordeaux mixture.

Nasturtium. White Rust. (Cystopus Candidus)

See under


Nectarine. Yellows, Etc

See under Peach.

Nerium. Black Mold (Capnodium Faedum)

Black velvety-like growth on leaves.


Spray with bordeaux mixture.

Nicotiana. Root-Rot (Thielavia Basicola)

Blackening and rotting of the roots of seedling plants.


Steam sterilization of seed-beds.

Mosaic Or Calico Disease

Enxymic disease. Mottling of leaf. Spread by touch.

Oak. Anthracnose (Gnomonia Veneta)

Brown spotting on under side of leaves, along veins. Brown pustules on spots.

Death of leaves and twigs. See under Arboriculture, Diseases of Trees.


Collect and burn all diseased twigs and leaves.

Spray with bordeaux mixture frequently from time buds swell.

Cenothera. Leaf-Galls (Synchytrium Fulgens)

Yellow swellings on the leaves.


Destroy affected leaves.


See under Hibiscus.

Olive. Limb-Gall, Or Knot (Pseudomonas Oleae)

Knots or galls on the twigs and limbs.


Remove and burn affected limbs.

Onion. Mildew (Peronospora Schleideniana)

Causes a wilt or blight of the leaves.


Spray with bordeaux mixture, 5-5-50, to which has been added one gallon of resin sal-soda sticker. First application when third leaf has developed, repeating every ten days until harvest time.