The following list shows in parallel columns (1) the symptoms which appear upon diseased plants or those with insect pests, (2) the cause and lastly (3) the indicated treatment.

Symptom

Cause

Treatment

Scab

Fungus

Bordeaux or lime-sulphur

Leaf spot

Fungus

Bordeaux, also gather and burn diseased leaves

Leaf curl

Leaf curl fungus

Lime-sulphur or Bordeaux

Canker

Freezing or rot fungus

Cut out and destroy diseased parts

Rust

Rust fungus

Bordeaux, also cut out cedar apples

Wilt

Fungus

Bordeaux

Twig blight

Fungus

Lime-sulphur, also cut out and burn diseased parts

Mildews

Mildew fungus

Sulphur dust, also burn leaves in autumn

Fruit rot

Anthracnose fungus

Bordeaux

Smut

Smut fungus

Bordeaux.

Tip burn (leaves)

Too much water followed by hot weather

Watch soil conditions

Scald

Freezing and thawing or fungus

Protect from winter sun and use Bordeaux

Gum excretion

Borers

Protective wash and dig out borers

Sawdust excretion

Borers

Protective wash

Leaf discolouration of conifers

Red spider

Dry sulphur dust

Bark discolouration

Scales

Lime-sulphur or kerosene emulsion

Leaf curling

Aphids

Nicotine sulphate or soapsuds

Wilt.

Cut worms

Paris green in molasses in bran

Symptom

Cause

Treatment

Defoliation

Bag worms or other caterpillars

Arsenate of lead and burn winter nests and egg masses

Defoliation

Rose slugs

Arsenate of lead

Defoliation

Leaf beetles

Arsenate of lead

Defoliation

Thrips

Nicotine sulphate

Leaf discolouration of rhododendrons

Lace-wing fly

Soap solution, I bar to 20 gallons.