PLANT PROTECTION 1 – Pests, Diseases and Weeds

PLANT PROTECTION 1 – Pests, Diseases and Weeds
LIST OF SOME
FUNGAL DISEASES
Plasmodium
Thick-walled
COMMON NAME SCIENTIFIC NAME HOST RANGE
(not exhaustive)
PHYLUM MYXOMYCOTA (slime moulds)
1. No mycelium. Body is a plasmodium (naked slimy mass of protoplasm) which grows
on low-lying parts of plants, does not infect them. Various colours, gray to yellow.
2. Sexual spores are thick-walled resting spores, which may survive for years in soil.
3. Asexual spores are thin-walled zoospores with flagella, which can swim in water.
Spores Slime moulds Fuligo, Physarum,
Diachea
Motile zoospores
Hyphae
Thick-walled
spores
Not known
in Australia
Zoospores
released from
sporangia
downy mildew
Zygospore
Cleistothecium
Hyphae
320 Fungal diseases - Biology, identification and classification
Non-parasitic, grows on turf,
onions, mulch material
PHYLUM PLASMODIOPHOROMYCOTA (endoparasitic slime moulds)
1. The body is a plasmodium within the cells of root and stems of plants.
2. Asexual spores are thin-walled zoospores.
Clubroot
Plasmodiophora brassicae Brassicas, eg cabbage, stock
Powdery scab
Spongospora subterranea Potato
PHYLUM OOMYCOTA (algal fungi, water moulds)
1. Mycelium present, hyphae well developed with few cross walls.
2. Sexual spores are thick walled resting spores called oospores.
3. Asexual spores may be:
Thin-walled zoospores with flagella which can swim in water and are produced in
sporangia. In some species conidia are produced.
Thick walled resting chlamydospores adapted to withstand adverse conditions.
ROOT ROTS
Crown and collar rots,
root rots
Phytophthora spp.
Some have a wide host range,
others are host specific
Damping-off
Pythium spp.
Seedlings. Other fungi can
Phytophthora spp.
also cause damping-off
Phytophthora root rot Phytophthora cinnamomi Wide range of plants
Sudden oak death P. ramorum Oak, over 40 plant genera
DOWNY MILDEWS
Downy mildews
Many genera, eg
Bremia lactucae
Peronospora destructor
P. parasitica
P. sparsa
P. violae
Pseudoperonospora cubensis
Plasmopara viticola
Usually host specific, eg
Lettuce
Onion
Brassicas, eg stock
Rose
Pansy
Cucurbits, eg pumpkin
Grape
MISCELLANEOUS DISEASES
Late blight, Irish blight Phytophthora infestans Potato, tomato, Solanaceae
Soft rot Rhizopus spp. Stored fruit & vegetables
White blister Albugo candida Brassicas
Anthracnose
Celery leaf curl
Colletotrichum fragariae
C. acutatum.
Strawberry
Celery
PHYLUM CHYTRIDIOMYCOTA (water moulds)
Water moulds Olpidium spp. Can transmit virus diseases
PHYLUM ZYGOMYCOTA (bread moulds)
1. Sexual thick-walled resting zygospores.
2. Non-motile asexual spores in sporangia, no motile zoospores.
Bread moulds Mucor, Rhizopus Stored fruit, vegetables
PHYLUM ASCOMYCOTA, IMPERFECT FUNGI
1. Mycelium present, well developed with cross walls.
2. Sexual spores:
Ascospores produced in groups of 8 in a sac-like ascus directly on the surface of
plant material or in special fruiting bodies, eg cleistothecia, perithecia, apothecia.
3. Asexual spores:
Thin-walled conidia which may be produced on the surface of the host or in
fruiting bodies eg pycnidia, acervuli, etc
Thick walled chlamydospores adapted to withstand adverse conditions.
ANTHRACNOSE DISEASES
Anthracnose
Sphaceloma rosarum Rose
Anthracnose
Gnomonia errabunda Plane trees
BLIGHTS
Blossom, flower, petal Botrytis cinerea
Wide range, eg flowers, fruit
blights, grey mould
Petal blight
Early blight of tomato
Ovulinia azaleae
Alternaria solani
geraniums, roses
Azalea
Potato, tomato, related weeds