Agriculture Reference
In-Depth Information
Importance
Although anthracnose causes leaf and preharvest fruit
diseases, it is most important as a postharvest problem.
Significant losses can occur between packing and
market, with infected fruit deteriorating rapidly during
transport.
Management
Apply recommended protectant and curative fungicides.
Remove affected fruit when packing and cool fruit
promptly after harvest to 7°C, as postharvest
anthracnose symptoms develop quickly.
Select varieties that are less susceptible to the disease.
BASE ROT
Cause
The fungus Fusarium solani (teleomorph Haematonectria
haematococca ).
Symptoms
Vines lose vigour and can suddenly wilt, and leaves may
go brown but are not shed. Considerable root decay
usually occurs and there may be a swelling or softening of
host tissue at the base of the vine. Adventitious roots may
form above the damage. The water-conducting tissues
inside the stem may be brown or reddish-brown in colour,
and the disease is often confused with Fusarium wilt.
Cankers that form on stems may turn red due to the
production of crimson perithecia of Haematonectria
haematococca .
Fig 15.6 The swelling at the base of the vine is caused by
Fusarium solani .
Management
Plant in free-draining soils.
Use pathogen-free nursery stock and ensure that nursery
plants do not have a bent root system ('J' root) or injuries
to the base of the stem.
Source of infection and spread
The fungus is a common inhabitant of soils in Australia
and infection requires a predisposing stress or injury. The
fungus may also be moved in apparently healthy nursery
stock.
In affected plantations, the spores of Haematonectria
haematococca may infect nearby vines through stem
wounds such as those caused by wire rub.
Importance
The disease can cause serious vine loss. The pathogen
is not particularly aggressive and infects vines that are
injured or under some form of physiological stress
(such as poor nutrition, poor root formation or water
logging). Major losses have occurred when the
pathogen has invaded lesions caused by Phytophthora
nicotianae .
Fig 15.7 Base rot on passionfruit showing white mycelium
and crimson perithecia of Haematonectria haematococca .
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