Verdia · Library
Mould and blight observations
Record whether growth is on living or decaying tissue, and see why Verdia sends Phytophthora infestans to mould and blight but other Phytophthora to root rot.
The only group with species exceptions
Verdia checks a two-word species map before it looks at the genus. Three names are in that map: Phytophthora infestans, Phytophthora ramorum and Phytophthora capsici. All three go to the mould and blight group, because they spread on leaves and fruit. Every other Phytophthora name goes to root and stem rot through the genus rule.
The group's genus list has ten entries: Botrytis, Botryotinia, Monilinia, Monilia, Sclerotinia, Penicillium and Rhizopus, plus the bacterial Erwinia, Pectobacterium and Dickeya. It has no keyword fallback.
Because this group has no keyword fallback, a result named only at family level, such as Sclerotiniaceae, shows its name and score but no steps.
What to record
- Note whether the growth is on living tissue or on parts that were already decaying.
- Record which leaves, stems, flowers or fruit are affected.
- Describe crowding around the plant and any prolonged damp conditions.
- Photograph the affected part and the plant as a whole on the same day.
Two Phytophthora results compared
A top result of Phytophthora infestans at 44 percent matches the species map and opens the mould and blight steps. This page repeats two: cutting away brown, soft or mouldy parts into the bin rather than the compost, and keeping leaves dry by watering the soil in the morning and giving more air. A result of Phytophthora cinnamomi at the same score skips the species map and lands in root and stem rot instead.
- Phytophthora infestans · 44%
- mould and blight, species rule
- Phytophthora cinnamomi · 44%
- root and stem rot, genus rule
- Botrytis cinerea
- mould and blight, genus rule
Frequent mistakes
- Reading the broad group label as a confirmed organism or a reason to buy a product.
- Putting mouldy material in the compost after reading the bin step.
- Assuming two Phytophthora results need the same response.
- Leaving out crowding and damp, which help a specific reference later.
What the group cannot tell you
The group combines different problems, with grey mould caused by Botrytis as one example. The RHS grey mould page listed below describes that disease; the ASPCA list is the source for pet safety.