cinerea) is probably the most common disease of
vegetables, ornamentals, tubers, corms, bulbs, fruit, as well as
many arable crops, and is almost certainly the most common disease
in glasshouses. Predominantly a blossom blight and a fruit rot, it
can also cause damping-off, stem canker, leaf spots and root rot.
Infection often spreads to other adjacent produce after harvest.
Small yellow-tan, depressed leaf
spots enlarge eventually coalescing to cover the leaf, then
sporulate as a light grey felt on the dying tissue.
Plants are rarely
infected directly by conidia, but indirectly though decaying petals or
leaves that stick to healthy leaves. After diseased fruit or fleshy
stems develop soft and watery pale brown rots, grey mould sporulates
profusely on them as they split open. Squat black sclerotia may form,
submerged within the tissue as it eventually wrinkles and dries. Seedling
infection is worse in cold damp soil. Bulbs, corms and tubers are
often infected while still in the ground. Lesions generally start at
the crown or base. These appear soft and watery then enlarge, turn
brownish spongy or corky, lose weight. Chrysanthemums develop
purple spots on their leaves and mummified flower buds. Any attack is
at the least disfiguring so prevention is best.
Botrytis cinerea overwinters in the soil on plant debris as
mycelium. Scierotia or infected plant debris can be spread with seed.
Growth and sporulation during cool damp weather favours release and
germination of conidia, and establishment of infection through wounds,
or via mycelium, on old flowers or dead foliage.
foot rots may also be caused by grey mould (Botrytis cinerea) that can
grow down the plant inside or over the outside of the stems and
between the leaves. On bedding plants, grey mould produces leaf
spotting of various types which may later behave as a general decay
organism if widespread necrosis occurs.
Impact/effects on chrysanthemums
Predominantly a blossom blight
and a fruit rot, it can also cause damping-off, stem canker, leaf
spots and root rot.
Iprodione - Rovral
For amateur gardeners: Cheshunt