Glossary · Orchard
Scab
Also written apple scab. Each is a name for the same thing, which is why none of them has an entry of its own.
Definition
A fungal disease, caused by Venturia inaequalis, producing olive-brown blotches on leaves and corky, cracked lesions on fruit. It reduces yield, disfigures fruit and opens the way for rots.
- Subject
- Orchard
- Also written
- apple scab
In more detail
Scab overwinters on fallen leaves and releases spores in wet spring weather, so leaf litter management on the orchard floor is a genuine control measure. For cider fruit, cosmetic scab matters far less than it does for dessert fruit — the apple is going to be milled — but severe infection weakens trees and cracked fruit admits Penicillium and the patulin risk that follows.
Where this is covered properly
The glossary defines; these pages explain. Each is described in its own words.
Microbiology
Venturia inaequalis
The cause of apple scab, the most widespread apple disease in temperate regions, and one whose consequences for cider fruit are far smaller than for dessert fruit.
Production
Pest and disease management
Keeping scab, canker, rots and the main insect pests to a level the orchard can carry, at a cosmetic standard well below dessert fruit but without allowing rot into the crop.
Related terms
Terms that belong to the same part of the subject, or that this one is routinely confused with.
Orchard
Canker
A fungal disease, caused by *Neonectria ditissima*, that forms sunken, cracked lesions on branches and trunks, girdling and killing the wood beyond them.
Fruit
Brown rot
A fungal rot of apples and pears, chiefly *Monilinia fructigena*, producing an expanding brown lesion with concentric rings of buff spore pustules. Affected fruit is unfit for milling.
Chemistry
Patulin
A mycotoxin produced chiefly by *Penicillium expansum* in rotting apples, regulated in apple juice and apple products because of its toxicity. Sorting out rotten fruit is the principal control.
Orchard
Orchard floor
The ground layer beneath the trees, and its management: permanent grazed grassland in traditional orchards, mown alleys with herbicide strips in intensive ones.
Where to go next
- Cider glossary — The whole vocabulary, by subject and A–Z.
- Comparisons — Terms that are only really clear when set against the thing they are not.
- Search — Finds terms by their aliases and by their spellings in other languages.
Sources
What this page rests on. Where a source is marked as registered rather than read, CiderHQ is recording that the body is authoritative on the subject without claiming to have worked through the document itself. See our evidence policy for what each state means.
NIAB (incorporating East Malling Research)
NIAB · research institute · retrieved 2026-08-24
East Malling developed the M-series apple rootstocks that determine tree size in essentially every modern orchard, cider orchards included. The authority CiderHQ uses for rootstock behaviour.