The region’s farmers are being urged to be vigilant in monitoring cereal crops for disease.
Cootamundra Industry and Investment Agronomist Phillip Bowden said he has a report of Wheat Streak Mosaic Virus (WSMV) in the Cootamundra district, with samples currently being lab tested for confirmation. Cases of the disease have also been reported in other areas.
Mr Bowden said he is confident the results would confirm this diagnosis.
Mr Bowden said there were a number of diseases being reported across NSW at present, which could prove a major issue for crops.
“With the excellent rainfall in February and March, many grazing wheat crops were sown early this season and we are now seeing Wheat Streak Mosaic Virus (WSMV) in some crops,” Mr Bowden said.
Heavy grazing had put a number of crops under stress, making them more susceptible to WSMV.
The virus, which can be transmitted in seed or by a microscopic mite, can cause a huge amount to damage to crops if not detected.
It (WSMV) has a range of symptoms; the main two being leaf mottling
(mosaic) and leaf streaking.
The disease first appears as light green streaks running parallel to the leaf veins. These streaks turn yellow and develop into blotches, giving the leaf a green and yellow pattern called a ‘mosaic’.
Tillers on affected plants tend to be less erect than those on uninfected plants. Affected plants can die prematurely or fail to grow, becoming stunted relative to healthy plants.
The virus is also evident in barley and triticale crops, however does not impact yield.
Early infection by WSMV causes the greatest yield loss. Most infected seedlings die early.
Plants infected between tillering and first node usually do not set any seed, while those infected between first node and booting have smaller seed.
Later infections cause progressively less damage, with only slight losses expected with spring infections.
Mr Bowden said management strategies needed to be put in place now to maximise use of the crop growth for grazing.
Spraying may also need to be carried out to ensure there are no further problems in ensuing seasons.
Mr Bowden said it is important farmers let their district agronomist know of any onset of disease so management strategies can be put in place to ensure the best result and prevent the spread of the virus.
Several rust samples have also been received in recent weeks, indicating that the beginning of the cereal cropping season in 2010 in eastern Australia is favouring both crop establishment and rust development.
Samples have confirmed cases of Wheat Stripe Rust, Wheat Stem Rust, Wheat Leaf Rust and Phalaris Leaf Rust in Southern NSW.
Crop surveillance in winter months is vital for growers, with growers urged to contact their local agronomist of any
suspected disease, so they can organise
for samples to be sent to the lab for
confirmation.
“We need to know if any of these diseases are present so we can do something about them,” Mr Bowden said.
Mr Bowden also warned there have been a lot of aphids present over summer and autumn, so growers should check crops carefully for this pest.
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