Agriculture Reference
In-Depth Information
Noogoora burr (
Xanthium pungen
s) and pigweed
(
Portulaca oleracea
). Spores of
Ve r t ic illium
can be spread by
wind and water, or in crop or weed debris.
Importance
Root-lesion nematode was once a serious problem in
strawberries but is now well controlled by using healthy
planting material from approved runner schemes.
Importance
The disease is often not noticed in strawberries, as plants
grow out of the symptoms. It can occasionally cause
serious losses.
Management
•
Plant runners from approved or certifi ed runner schemes.
Do not grow legumes such as cowpea, French bean, lab
lab bean and mung bean in rotation with strawberries on
infested land, because these beans are hosts of the
nematode.
•
Management
•
Fumigate the soil.
Ensure that the soil is well drained.
Apply pre-plant nematicides in infested areas.
•
•
Plant runners from approved or certifi ed strawberry
runner schemes.
•
STRAWBERRY BUD NEMATODE (CRIMP
DISEASE) (
APHELENCHOIDES BESSEYI
)
When using runners from your own property, make sure
they are from disease-free areas.
•
Symptoms
Plants affected by crimp disease are more compact than
healthy plants; leaves are darker green, deformed and
sometimes strap-like, particularly those in the crown. Many
leaf lets show rough greyish or silvery feeding areas near the
base of the main veins. Flowering is delayed and berries are
deformed. Fruit stalks are often shortened. Symptoms are
generally not obvious after early August in Queensland, but
reappear on the runners in November-December.
Clean cultivation implements to avoid spreading
infested soil.
•
Do not plant in infested areas.
•
NEMATODES
ROOT-KNOT NEMATODE
(
MELOIDOGYNE HAPLA
)
Source of infection and spread
The nematode is usually introduced in infested runners.
Nematodes congregate on small, undeveloped leaves, on
f flowers in the crown, and occasionally around the seeds.
Bud nematodes move over and between plants via a thin
film of moisture provided by rain or dew.
Refer to the description of root-knot nematode in the
chapter on Common diseases in perennial fruit crops.
ROOT-LESION NEMATODE
(
PRATYLENCHUS VULNUS
)
Symptoms
Premature browning and death of roots occur. Infested
plants may grow satisfactorily until mid-season, after
which they decline and are unsuitable for ratooning. Root-
lesion nematode damage is almost impossible to diagnose
on symptoms alone.
Source of infection and spread
The nematodes are soil inhabitants and other hosts include
legumes, grapes and stone fruit. Spread occurs in infested
runners and in contaminated soil. Most strawberry farms
are free from root-lesion nematode and will remain so
unless these are introduced on infested planting material
or in soil from other farms.
Fig 18.37 Crimp disease caused by strawberry bud nematode. Leaves
in the centre of the plant are green and deformed.
