Try to avoid or prevent any of the factors that can lead to plant damage or stress. For example:
- Prevent or control pests such as cypress aphid
- Ensure that newly-planted conifers establish well
- Water plants during periods of extended drought
- Avoid unnecessary physical damage
- Prune hedges at the correct time of year (hedge pruning times)
- Avoid pruning during prolonged periods of wet weather (which are suitable for spore germination and infection), or during drought conditions (which can itself result in dieback)
If dieback due to Pestalotiopsis is diagnosed, pruning out the affected shoots will reduce the number of spores available to set up new infections. However, remember that many conifers will not produce new growth if they are cut back hard into old growth.
There are no fungicides available to amateur gardeners with specific recommendations for use against Pestalotiopsis. However, the fungicides tebuconazole (Provanto Fungus Fighter Concentrate), tebuconazole with trifloxystrobin (Provanto Fungus Fighter Plus, Toprose Fungus Control & Protect), and triticonazole (Scotts Fungus Clear Ultra and Scotts Fungus Clear Ultra Gun) are labelled for the control of other diseases on ornamental plants, and could therefore be used legally on conifers (at the owner’s risk) to try and control Pestalotiopsis.
There is no specific information available as to the efficacy of these products against the fungus, however. It is possible that repeated sprays would be required where the disease is present, particularly during unsettled weather.
The following products contain a combination of both insecticide and fungicide, enabling the control of both insect pests and disease: myclobutanil containing cypermethrin (Westland Resolva Rose 3 in 1, Doff Rose Shield Bug & Fungus Killer, Scotts Roseclear Ultra Gun 2, Vitax Rosegarde) and triticonazole containing acetamiprid (Scotts Roseclear Ultra and Scotts Roseclear Ultra Gun).When a proprietary product contains an insecticide as well as a fungicide it would be preferable to use an alternative product if pests are not a problem on the plants treated.
Inclusion of a product does not indicate a recommendation or endorsement by the RHS. It is a list of products currently available to the home gardener.
Fungicides for gardeners (Adobe Acrobat pdf document outlining fungicides available to gardeners)
Chemicals: using a sprayer
Chemicals: using safely and effectively
Chemicals: storing and disposing safely