Scientific Name: Tranzschelia pruni-spinosae
(also previously listed under Tranzschelia discolor depending on taxonomy source)
| Common Name | Stone Fruit Rust |
|---|---|
| Causal Agent | Tranzschelia pruni-spinosae (fungus) |
| Pathogen Type | Fungal (rust fungus – Basidiomycete) |
| Primary Hosts | Peach, nectarine, apricot, plum, cherry |
Upper leaf surface: yellow, angular to circular chlorotic spots
Underside of leaves: rust-colored pustules (uredinia) that may darken as season progresses
Premature defoliation, especially noticeable in late summer to early autumn
Possible sunburn and reduced fruit yield due to canopy loss
Humid, wet weather, especially late in the growing season
Dense canopies with poor air circulation
Overhead irrigation increasing leaf wetness duration
Repeated infections from overwintering spores in fallen leaves
| Practice | Recommendation |
|---|---|
| Cultural Control | Prune to increase air circulation and reduce humidity |
| Sanitation | Remove and destroy infected leaf litter post-harvest |
| Fungicides | Apply protectant and systemic fungicides (e.g. strobilurins, DMIs) from late spring to early autumn, especially in high-risk conditions |
| Irrigation | Prefer drip irrigation to avoid wetting foliage |
| Monitoring | Scout from mid-summer; focus on shaded, moist areas in the canopy |
| Tranzschelia discolor |
Scientific Name: Tranzschelia pruni-spinosae
(also previously listed under Tranzschelia discolor depending on taxonomy source)
| Common Name | Stone Fruit Rust |
|---|---|
| Causal Agent | Tranzschelia pruni-spinosae (fungus) |
| Pathogen Type | Fungal (rust fungus – Basidiomycete) |
| Primary Hosts | Peach, nectarine, apricot, plum, cherry |
Upper leaf surface: yellow, angular to circular chlorotic spots
Underside of leaves: rust-colored pustules (uredinia) that may darken as season progresses
Premature defoliation, especially noticeable in late summer to early autumn
Possible sunburn and reduced fruit yield due to canopy loss
Humid, wet weather, especially late in the growing season
Dense canopies with poor air circulation
Overhead irrigation increasing leaf wetness duration
Repeated infections from overwintering spores in fallen leaves
| Practice | Recommendation |
|---|---|
| Cultural Control | Prune to increase air circulation and reduce humidity |
| Sanitation | Remove and destroy infected leaf litter post-harvest |
| Fungicides | Apply protectant and systemic fungicides (e.g. strobilurins, DMIs) from late spring to early autumn, especially in high-risk conditions |
| Irrigation | Prefer drip irrigation to avoid wetting foliage |
| Monitoring | Scout from mid-summer; focus on shaded, moist areas in the canopy |
