Green Industry - A Knowledge Portal for Commercial Horticulture in Wisconsin (sponsored by University of Wisconsin-Extension)
Diagnostics - Problem Details
Phomopsis twig blight - Phomopsis juniperovora
Description
A shoot tip disorder of Junipers.
Damage
Initially, small gray lesions (spots) form on the terminal four to six inches of new shoots in early spring. Infected branches typically first turn dull red or brown, and finally ash-gray as lesions expand to girdle and kill branch tips. Small, black pycnidia (the reproductive structures of the causal fungus) can easily be seen on dead branches with the unaided eye or with a hand lens. Severe infections may result in death of an entire plant.
Cultural Controls
It is important to remove and destroy dead and infected twigs. Resistant species and varieties are available.
Remarks
Begin applications, at labled intervals, when new flushes of growth appear. Protect until foliage is mature.
Chemical Controls
- Azoxystrobin
- Signal Word: Caution
Pesticide Class: Systemic-Upward only - Chlorothalonil+Thiophanate methyl
- Signal Word: Danger
Pesticide Class: Protectant, Systemic-Upward only - Copper
- Signal Word: Caution
Pesticide Class: Protectant - Copper hydroxide
- Signal Word: Danger
Pesticide Class: Protectant - Copper sulfate
- Signal Word: Caution
Pesticide Class: Protectant - Copper+Mancozeb
- Signal Word: Danger
Pesticide Class: Protectant - Iprodione+Thiophanate-methyl
- Signal Word: Caution
Pesticide Class: Local Protectant, Systemic-upward only - Mancozeb
- Signal Word: Caution
Pesticide Class: Protectant - Mancozeb+Thiophanate-methyl
- Signal Word: Caution
Pesticide Class: Protectant, systemic-upward only - Propiconazole
- Signal Word: Warning
Pesticide Class: Systemic-upward only - Thiophanate-methyl
- Signal Word: Caution
Pesticide Class: Systemic-upward only
Locations Affected
Plant Environment
Scouting Season:
May - Early , May - Mid , May - Late , June - Early
Plants Affected
Photos
Close up of pycnidia, fungal fruiting bodies of Phomopsis, on Juniper species.
More Phomopsis fruiting bodies on Juniper species.
Discolored foliage on Juniper seedlings infected by Phomopsis.
General symptoms caused by Phomopsis twig blight on Juniper species.
Tip dieback on Juniper species caused by Phomopsis.