Diff: Downy Mildew and Botrytis

== Downy Mildew and Botrytis ==

== Downy Mildew and Botrytis ==

Downy mildew and botrytis both become more important when conditions are cool, moist, humid, or crowded. They can be confused with other rose problems from a single photo.

Downy mildew and botrytis both become more important when conditions are cool, moist, humid, or crowded. They can be confused with other rose problems from a single photo.

=== Downy mildew signs ===

=== Downy mildew signs ===

* Angular purple, red, or brown leaf patches, often limited by veins.

* Angular purple, red, or brown leaf patches, often limited by veins.

* Yellowing and quick leaf drop.

* Yellowing and quick leaf drop.

* Pale growth on leaf undersides may appear in humid conditions.

* Pale growth on leaf undersides may appear in humid conditions.

* Can be more sudden and severe than black spot.

* Can be more sudden and severe than black spot.

=== Botrytis signs ===

=== Botrytis signs ===

* Spotted petals and buds that fail to open.

* Spotted petals and buds that fail to open.

* Grey-brown fuzzy mould on decaying petals, buds, or stems.

* Grey-brown fuzzy mould on decaying petals, buds, or stems.

* Problems during cool wet spring or autumn weather, or in very humid sheltered sites.

* Problems during cool wet spring or autumn weather, or in very humid sheltered sites.

=== Controls ===

=== Controls ===

* Increase air circulation by spacing and pruning.

* Increase air circulation by spacing and pruning.

* Avoid irrigation that leaves flowers and foliage wet for long periods.

* Avoid irrigation that leaves flowers and foliage wet for long periods.

* Remove and dispose of infected flowers, buds, leaves, and cane material.

* Remove and dispose of infected flowers, buds, leaves, and cane material.

* Reduce dense groundcover around roses where humidity stays high.

* Reduce dense groundcover around roses where humidity stays high.

* For downy mildew, environmental management is often more realistic than rescue spraying in home gardens.

* For downy mildew, environmental management is often more realistic than rescue spraying in home gardens.

=== Direct treatment notes ===

=== Direct treatment notes ===

* Fungicide labels for downy mildew and botrytis are more specific than general rose disease sprays. Do not assume a black spot product controls downy mildew.

* Fungicide labels for downy mildew and botrytis are more specific than general rose disease sprays. Do not assume a black spot product controls downy mildew.

* Check local extension, RHS, HSE, or EU/member-state authorisations before product use.

* Check local extension, RHS, HSE, or EU/member-state authorisations before product use.

* Severe suspected downy mildew, nursery-stock issues, or repeated rapid defoliation should be escalated to a diagnostic service.

* Severe suspected downy mildew, nursery-stock issues, or repeated rapid defoliation should be escalated to a diagnostic service.

=== Sources ===

=== Sources ===

* [UC IPM: Roses diseases and abiotic disorders](https://ipm.ucanr.edu/home-and-landscape/roses-diseases-and-abiotic-disorders/)

* [UC IPM: Roses diseases and abiotic disorders](https://ipm.ucanr.edu/home-and-landscape/roses-diseases-and-abiotic-disorders/)

* [Penn State Extension: Rose Diseases Outdoors](https://extension.psu.edu/rose-diseases-outdoors/)

* [Penn State Extension: Rose Diseases Outdoors](https://extension.psu.edu/rose-diseases-outdoors/)

* [RHS: Rose problems FAQ](https://www.rhs.org.uk/plants/roses/frequently-asked-questions)

* [RHS: Rose problems FAQ](https://www.rhs.org.uk/plants/roses/frequently-asked-questions)

* [UK HSE: Garden home pesticide guidance](https://www.hse.gov.uk/pesticides/using-pesticides/garden-home.htm)

* [UK HSE: Garden home pesticide guidance](https://www.hse.gov.uk/pesticides/using-pesticides/garden-home.htm)

[[Category:Diseases]]

[[Category:Diseases]]

[[Category:Care]]

[[Category:Care]]