Control

Plant diseases and their treatments can be categorised into broad types, and similar responses are recommended within these types.

 

Note

The advice provided in this site is intended as a guide only.
 
In undertaking any suggested method for destroying diseased or infected trees or plants that involves applying any chemical treatments, it is important to read the manufacturer’s instructions for use and associated safety data.
 
Take all necessary safety precautions if burning infected plant material and never burn material where there may be any risk to life or property. You should always consult SEPA prior to burning material to ensure you have any required permissions or licences.
 
You should seek further advice from the relevant authorities listed in this site if you are in any doubt as to how to treat or destroy infected plants or trees.

About This Page

If you can identify the cause of a plant disease, it is always best to check specific resources for tailored advice to control it. This is particularly true for notifiable pests. It is often the case however that notifiable diseases can be ruled out, yet the precise cause is not known or falls into a broad category such as 'fungal root rot' or 'leaf rust'. For this situation we have compiled generalised advice for the control of different kinds of plants diseases. This advice will usually apply to most diseases within the category and may be taken as general guidance, but note that exceptions will abound!

Getting Started

If you are uncertain of the type of problem affecting a plant, follow these steps:

  1. Determine the general cause and the extent of the disease symptoms. Look for insect damage such as leaf galls or insect exit holes in the bark, or for signs of fungi or other organisms such as brackets on boles of living trees or leaf spots. Note that some damage can be caused by abiotic factors (such as frost). A field guide such as the CABI Field guide for the identification of damage on woody sentinel plants can help to pinpoint causes of disease.
  2. Use Recommended Sources to try to identify the causal organism and to determine if it is a common and or/native species, and whether it is disease-causing or just a saprophyte (living of the dead plant that something else has killed).
  3. Search the Threats page by Host for diseases on the Pest Risk Register to determine whether you need notify authorities. If you think it might be a notifiable organism notify authorities and follow their instructions – do not try to eradicate it unless so instructed.
  4. If you can identify a causal organism, consult the listed resources for specific guidance on control. For generalised advice, check these Prevention – Biosecurity  and Control pages to learn ways to help keep the disease from spreading, and what kinds of control responses are available for non-notifiable diseases.

Disease Types

  • In addition to Wilts and Vascular Diseases, pests of roots and wood can cause structural instability. Decaying roots or the presence fruiting bodies of bracket or other wood rot fungi can indicate heart rot, and structural instability in trees.

    • Consult an arborist if trees may pose a hazard to humans.
    • Wood rot fungi are an essential part of natural ecosystems, and are to be expected on any fallen wood. Most of these are non-pathogenic or only weak pathogens, and are not a cause for concern.
    • Wood and root rots in living trees can, however, signal a larger problem or a more aggressive pathogen.
    • Prevention is the best way to minimise wood and root rots.
      • Follow biosecurity guidance to reduce opportunities for introducing root and wood rotting pathogens on soil, plants for planting, or tools and equipment.
      • Most wood rot pathogens are weak pathogens but will opportunistically infect wounds or otherwise stressed plants, so minimising mechanical damage will help keep plants healthy.
      • Maintaining good spacing among plants, good drainage, and otherwise un-stressed plants can help prevent root and wood rots.
      • Wood rot fungi are expected to be found on already-dead wood, and usually are not a cause for concern. If, however, an otherwise healthy tree has been heavily damaged or killed by root and wood rots such as Armillaria spp., it can be helpful to remove the stump and as much of the root mass as possible.
      • Wood and roots infected with root and wood rot pathogens should not be chipped and used for mulch or in home compost.