1. Technical Bulletin
    Our monthly technical bulletin is designed to highlight some of the most common threats and issues affecting the horticultural industry. We will also be offering useful technical information as well as tips and advice across a wide variety of subjects. All the items featured in this months e-shot contain links to specialist websites where you can discover more about them.

    Rust is one of the most common fungal diseases found on plants. It can be a problem aesthetically and in severe cases it can kill the host plant. It is most commonly found on the underside of the leaves and will leave pale spots on the surface of the foliage. Rust colours vary depending on the type and the host plant that they are affecting. They can range from orange all the way through to white or black

    RHS information on rust:
    Common rusts found on herbaceous:
    Buff Tip Moth Caterpillar

    These are large yellow and black caterpillars that affect a wide range of shrubs and trees. The moths of the caterpillar resemble a broken twig. It is often the caterpillars that are spotted first as they are hairy with yellow and black markings.

    The caterpillars can usually be found from July to October. The moths, after overwintering as pupae, emerge from late May to July. This shouldn’t affect the long-term health of any large trees but can cause severe defoliation on smaller trees. The most common plants affected are Oak, Hornbeam, Lime and Birch.
    RHS information on buff tip moth caterpillar:

    Wildlife trust information on buff tip moth:

    Honey Fungus

    This is the common name given to different species of Armillaria. This fungus will affect the roots of the host plant causing them to die. You will sometimes get clumps of honey coloured toadstools appear in the autumn.

    No plants are completely immune to this disease but many have good resistance to the fungus. Initially upper plants of the plant may be seen to be dying back, produce smaller leaves or have reduced flowering. This can also happen over several years with branches slowly dying back.
    RHS information on honey fungus:
    Susceptible and resistant plant list:
    Viburnum Beetle

    Viburnum beetle can completely defoliate any plant that it attacks. The majority of the damage is caused in the spring by the larvae but there can be further damage done in late summer by the adults.

    Damaged foliage is often discoloured, and there are large holes in the leaves of the plants. The larvae are creamy yellow, with black markings about 8mm long. The adults are greyish brown and can be found from late July to September.
    RHS advice on Viburnum Beetle:
    Horticulture Week article on Viburnum Beetle:

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