Panama disease tropical race 4: Identifying and reporting suspect plants

Panama disease tropical race 4: Identifying and reporting suspect plants


There are both internal and external symptoms
associated with the disease. The external symptoms include: leaf yellowing, wilting
of leaves & stem splitting. The first symptom that is likely to appear
is yellowing of the lower or older leaves. This typically occurs from the leaf edges
and continues further into the leaf towards the midrib. You may initially notice that
the plant lacks a healthy green colour in the leaves and that the edges or parts of
the leaves will be pale or starting to yellow before dying. It is important to report ANY plants that
have yellow leaves, even if they are showing symptoms that are similar to those you have
seen in the past. As the lower leaves die they wilt and collapse
forming what can be described as a skirt of dead and dying leaves around the plant. Sometimes
the dead leaves may remain upright. The younger leaves may also start to yellow, although
depending on the severity of the infection, may remain green and upright. Another symptom to keep an eye out for is
splitting of the stem. Early splitting will usually occur at the base of the plant and
only extend a couple of layers into the stem. However in later stages of the disease this
splitting can become more obvious and extend much further up and into the stem. It’s important to keep a keen eye out for
infected plants, as these may appear within, and be obscured by, healthy looking plants.
As an exercise see how many sick plants you can spot in this photo? The main internal symptom of the disease is
discolouration or darkening within the stem. This darkening can range in colour from reddish
to dark brown to black and is particularly obvious in later stages of the disease. It
is very important that you do not attempt to cut the stem of any suspect plants. Cutting
an infected plant triggers the fungus to produce spores that can survive in the soil for decades.
Cutting or removing plants also increases the risk of spreading the disease and also
affects the integrity of the sampling process required to confirm or rule out the presence
of Panama Tropical Race 4. If you do find plants showing any of the external
symptoms mentioned, report them as soon as possible to your farm supervisor. Talk with
your farm supervisor or farm manager about how and when this should be done. The usual
method is to mark the suspect plant with flagging tape or paint and also mark the end of the
row that the plant is in. It’s also a good idea to make note of the block as this will
aid in re-locating the suspect plant. If you have a camera or mobile phone, take photos
to aid in identification. If possible photograph the whole plant, a close up of the yellowing
or wilting leaves, any stem splitting that is evident and any other symptoms that you
see. Your farm manager or supervisor may also mark
the location of the suspect plant onto a farm map to further assist in locating the plant.
Remember to look out for any plants that have yellow leaves, wilting leaves or stem splitting.
Also if you see a suspect plant, remember, do not cut the stem, as this can cause the
disease to spread. In Queensland, Panama disease tropical race
4 is a notifiable disease under the plant protection Act. This means that by law you
and your farm manager must report any suspect plants to Biosecurity Queensland within 24
hours of sighting them. For more information or to report suspect
plants, contact Biosecurity Queensland on 13 25 23. It is in everyone’s interest to report potentially
diseased plants as soon as they are detected. It’s through a combination of early detection,
identification and on-farm biosecurity that we can limit the spread of this disease and
ensure the future of the Australian Banana Industry.


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