Diseases & Disorders

Helpful advice on what to do when problems strike, whether they're diseases, disorders or otherwise - and how to prevent them occurring


Fungal infection

Phytophthora is our second most reported disease. Causing die-back and leaf damage on trees and shrubs and is often fatal.

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  • Magnesium deficiency shown by the tomato leaves. Credit:RHS/Tim Sandall.

    Tomatoes: leaf problems

    Although easy to grow and very rewarding, tomatoes can suffer from a range of easily preventable leaf problems.

  • Verticillium wilt on tomato. Credit: RHS/Pathology.

    Tomatoes: stem problems

    Although easy to grow and very rewarding, tomatoes can suffer from a range of problems with their stems, from the lumps and bumps of root initials to more serious stem rots caused by a variety of diseases.

  • Tree rust on Sorbus RHS

    Tree rusts

    Tree rusts are fungal diseases causing dusty orange, brown or black spots (pustules) on the leaves of poplar, willow, birch and plum, and cankers on the stems and branches of five-needled pine.

  • Trees and shrubs: establishment problems

    Trees and shrubs: establishment problems

    It can be frustrating when trees and shrubs fail to establish well. The main symptoms of poor establishment are yellow or brown leaves and shoots dying back. There are steps you can take to remedy the situation, but it is better to try and prevent these problems happening in the first place.

  • Trees and shrubs: scab diseases

    Trees and shrubs: scab diseases

    Scab diseases of trees and shrubs can disfigure the plant by producing unsightly dark spots on the leaves. Blossoms and fruit can also be attacked and the vigour of the plant reduced as a result of premature defoliation.

  • Tulip fire. Image: RHS, Horticultural Science

    Tulip fire

    Tulip fire is a fungal disease of tulips caused by Botrytis tulipae, which produces brown spots and twisted, withered and distorted leaves. It is so named because plants appear scorched by fire.

  • Tulip infected with a virus. Image: RHS, Horticultural Science

    Tulip viruses

    Many viruses affect tulips, causing streaked flowers, mottled leaves, distorted plants and stunted growth.

  • Verticillium wilt on Cotinus. Image: RHS, Horticultural Science

    Verticillium wilt

    Verticillium wilt is a soil-borne fungal disease of many fruit, vegetables and ornamental plants that enters the plant through the roots. Infection with this fungus causes dieback and the leaves to wilt.

  • Walnut leaf blotch

    Walnut leaf blotch

    This fungal disease of walnut trees is unsightly, and in wet summers can cause significant early leaf fall. Unfortunately, it can also affect the fruit of the tree, rendering the walnuts useless.

  • Waterlogged lawns

    Waterlogged lawns

    Lawns can become waterlogged if water sits on the surface and drains slowly. Waterlogging is more likely to be a problem on compacted and clay soils. However, it is worth noting that patches of dead grass where the soil proves very difficult to re-wet can be caused by a fungal problem: dry patch.

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