Bulletin 25 2010 - BSES

14 Ramu
BiOseCuriTy feATure / pArT 5 rAMu sTuNT
1
rAMu sTuNT
iN This BuLLeTiN’s BiOseCuriTy feATure, Bses reseArChers BArry CrOfT,
rOB MAGArey AND NADer sALLAM Offer Our reADers AN iNsiGhT
iNTO rAMu sTuNT.
stunt was first detected (and has
only been found) in Papua New Guinea
(PNG) where it is recognised as a major
disease. In 1986, Ramu stunt almost
destroyed the entire sugarcane industry
at Gusap plantation in PNG. A 60%
reduction in productivity was recorded
in the highly susceptible cultivar ‘Ragnar’,
which at that time occupied 90% of
the plantation.
Stools infected with Ramu stunt show
severe stunting and eventually die.
In infected plants the leaves become
short, stiff and erect (Images 1–6). leaf
symptoms vary with variety; some show
stunting and chlorosis while in others leaf
flecking is more predominant.
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2 3
biosecurity feature
CAuse Of The DiseAse
Recent work of BSES Indooroopilly based
researcher Dr Kathy Braithwaite has led to
a major breakthrough. She has identified
a new virus in cane infected with Ramu
stunt. Kathy’s research to characterise the
virus is ongoing.
spreAD Of The DiseAse
A small plant hopper called Eumetopina
flavipes spreads Ramu stunt. The disease
can also spread through infected planting
material. E. flavipes is 3–5 mm in length
and has a distinctive black colour (Image 7).
5 6
Another planthopper common in
Australian sugarcane fields (Perkinsiella
saccharicida) is grey-brown in colour and
does not transmit Ramu stunt.
E. flavipes is widespread in the islands of
the Indonesian Archipelago and is present
on many of the Torres Strait islands; a
small population also survives on the
Australian mainland at Bamaga and New
Mapoon on Cape York. However, the
Australian populations do not harbour the
disease, and this insect has never been
found on Australian commercial crops.
Growers who see this insect on their crops
should contact their nearest BSES office
immediately.