Pests and Pathogens
M.W.Hanson
The following are just a few of the pests and diseases recorded at Hylands 2000 - 2003. Historically
the earliest fungal pest recorded must be the dry-rot found in the utility buildings between the main
house and stable block and which caused the ultimate demolition of the buildings. Dry-rot is caused
by the fungus Serpula lacrymans.
The park and gardens have provided a few records of interest, among them the Tar Spot (Rhytisma
acerinum) on Sycamores in the Ice-House Plantation. Black Spot, a Discomycete fungus
(Diplocarpon rosae) was noted on some of the rose cultivars previously on the Rose Terrace. The
Oak Mildew (Microsphaera alphitoides) is widespread on small scrubby oaks in the park. Dutch
Elm Disease, caused by a fungus of the genus Ophiostoma, still infects elms in the park (in the
formal gardens and elsewhere). The bark beetle Scolytus scolytus, which is thought to carry the
spores, is known from the park.
Rhododendron bud-blast is common on Rhododendrons in the formal gardens area (in January
2003 what was presumably the same species was found on Azaleas as well). Bud-blast is caused by
a Hyphomycetal fungus (Pycnostysanus azaleae) and is thought to be carried by the introduced
North American leaf-hopper Graphocephala fennahi. The leaf-hopper is sometimes abundant on
the Rhododendrons around the north lawn in July and August.
A rust on both wild and cultivars of the daisy (Bellis perennis), including the Pomponette variety,
is thought to be the introduced New Zealand fungus Puccinia distincta.
Many of the mature trees, particularly the oaks, are parasitised by bracket fungi, perhaps the most
obvious and frequent of these being the bracket fungus Ganoderma australe (syn. adspersum).
Rarerbrackets on oaks include Ganoderma resinaceum and the beautiful Inonotus dryadeus. Botrytis
fungus has been noted on Geranium leaves, usually in wet conditions in the formal gardens.
Notable 'pest' plants in the wider park include Impatiens glandulifera and Senecio jacobaea.
Crassula helmsii is noted from the Marconi Fishing Lake - it is to be hoped it does not spread to
the park ponds. Brambles (Rubus sp.) can be a problem growing through the Rhododendrons where
they are very difficult to control.
Insect pest species recorded include flie woolly aphid (Eriosoma lanigerum) on apple cultivars, the
hoverflies Merodon equestris and Eumerus tuberculatus, presumably on the cultivated bulbs in the
formal gardens, and the wood-boring beetles Anobium punctatum and Xestobium rufovillosum.
The introduced scale insect Pulvinaria regalis, although forming dense colonics on trees as near as
Widford, is known from only two trees in the park (a Horse Chestnut and a Maple), but so far with
only one or two individuals. Rather than being a vector of diseases, it disfigures the appearance of
the tree when there is a heavy infestation.
Various slugs and snails are known pest species, including the snail Helix aspersa (which is actually
uncommon in the park) and the slug Tadonia budapestensis. Both these species are imported amongst
pots and trays of bedding plants.
Essex Parks: Section 2 - Hylands Park
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