15 Common Plant Diseases

Keep your garden neat to prevent any diseases or disorders, like these common infections.

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©2012, Dorling Kindersley Limited

©2012, Dorling Kindersley Limited

©2012, Dorling Kindersley Limited

©2012, Dorling Kindersley Limited

©2012, Dorling Kindersley Limited

©2012, Dorling Kindersley Limited

©2012, Dorling Kindersley Limited

©2012, Dorling Kindersley Limited

©2012, Dorling Kindersley Limited

©2012, Dorling Kindersley Limited

©2012, Dorling Kindersley Limited

©2012, Dorling Kindersley Limited

©2012, Dorling Kindersley Limited

©2012, Dorling Kindersley Limited

©2012, Dorling Kindersley Limited

Blossom End Rot Classic Symptom of Weather

A water soaked spot at the blossom end of tomato fruits is the classic symptom of blossom end rot. It is most common when the growing season starts out wet and then becomes dry when fruit is setting. Fruit should be picked and discarded.

Tomato and Potato Blight Affects Plant Foliage

Potato and tomato blight is a disease of the foliage and fruit or tubers of tomatoes and potatoes, causing rotting. It is most common in wet weather. Infected material should be buried or burned rather than composted. Rotate crops each year.

Cucumber Mosaic Virus Causes Stunted Growth

Cucumber mosaic virus is one of the most common plant viruses causing yellow mottling, distorted leaves and stunted growth in a wide range of garden plants, not just cucumbers. Destroy suspect plants promptly to reduce the risk of transmission.

Powdery Mildew Cause White Dusty Powder on Plants

Powdery mildews are a group of related fungi which attack a wide range of plants, causing a white, dusty coating on leaves, stems and flowers. Destroy infected leaves, mulch and water to reduce water stress, and prune out infected shoots.

Halo Blight Destroys Plants with Bacterial Fungus

Halo blight is a bacterial disease carried on the bean seeds, which causes the leaves to have brownish, water soaked spots that are surrounded by a yellow halo. There are no remedies, so infected crops should be destroyed, but using fresh seed will help.

Bitter Pit Affects Apples Late in Season

Bitter pit is a common disorder that causes dark spots on apples late in the season or in storage. This condition is related to lack of calcium in fruit and is often as a result of dry soil conditions. It can be prevented with good cultivation practices.

Apple Scabs Blemish Fruits Making Them Inedible

Apple scab is a fungal disease most common in areas of relatively high rainfall and relative humidity. If uncontrolled, the fungus may defoliate trees and blemish fruit to a point where it is unmarketable.

Lettuce Downy Mildew is Fungal Disease of Leaves

Downy mildew of lettuce is a fungal disease causing yellow patches and fuzzy white mold on leaves. These patches turn brown as the leaf tissue dies. It affects seedlings and mature plants. Remove infected leaves to prevent spore release into soil.

Rust Disease Caused by Lack of Air Circulation

Rust disease causes leaves to look yellow and unsightly. It usually develops in late summer or autumn. Large numbers of tiny, spore producing pustules break through the leaf surface giving a rusty like appearance. Remove and destroy affected plants.

Strawberry Virus Affects Yield of Berries

Several viruses infect strawberries to cause a wide range of symptoms which result in poor vigour and low yield. Always buy plants which are certified as virus free. Destroy and replace plants as soon as yields start to fall and rotate crops.

American Gooseberry Mildew Result of Stagnant Air

American gooseberry mildew is a common disease caused by a group of fungi producing powdery mildews on a wide range of plants and is the most serious disease of gooseberries. Gooseberries are best pruned to an open form to discourage stagnant air.

Peach Leaf Curl Caused by Fungus

Peach leaf curl is a fungal disease of peaches, almonds, nectarines and apricots, which causes severely distorted leaves, making them fall prematurely. Prompt removal of infected leaves before bloom of white spores appears helps reduce amount of fungus.

Broad Bean Chocolate Spot Caused by Poor Air Flow

Chocolate spot is one common fungal diseases of broad beans. Fungus causes dark, chocolate colored spots on all parts of plant. Maximise air flow around plants by wider spacing and avoid damp, humid sites. Destroy infected plants at end of season.

Potassium Poor Plants Fail to Thrive

If plants fail to thrive, despite adequate soil preparation, watering and mulching, it may be a sign of potassium deficiency. Yellow or reddish colored leaves, stunted growth and poor flowering are all common symptoms.

Yellowing Plants in Spring Need Nitrogen

Nitrogen promotes green, leafy growth and deficiency results in yellowing and stunted growth. Nitrogen is very soluble, so is easily washed out of the soil in winter rains, leaving the soil deficient in spring, just when plants are putting on new growth.

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