Saturday 26 May 2012
Headlines
Did you find this story interesting? (0) (0)
20/10/2007
Autumn aphid feeding risks BYDV spread
Numbers of the aphids most responsible for spreading Barley Yellow Dwarf Virus are continuing to increase this season, with mild conditions and the high proportion of early sown crops increasing the risk of disease spreading.
Although populations of the Bird Cherry Aphid and Grain Aphid - which pose the greatest threat of transmitting the virus - have hitherto been relatively low, results of the latest national aphid monitoring surveys revealed a 40% increase in numbers of these two key aphid species caught over recent weeks on comparative sites (to 7 October).
"The risk of BYDV infection appears to be shifting ever later; cereal crops emerging before the second week of October - which could be as high as 60% in the highest risk areas - must now be considered as most susceptible to BYDV infection," warns Syngenta Technical Manager, Iain Hamilton. "The earlier crops are infected, the higher the severity of disease will be and the greater the yield loss."
Where mild conditions continue, there is also the chance for secondary infection. Aphids feeding on infected crops pick up disease and perpetuate its spread across the field and to surrounding crops right through the autumn and early winter, he adds.
"Growers need to weigh up the risk based on the timing of the crop emergence and the historic legacy of BYDV on their farm, allied to the current level of aphid activity," he advises. With a lower risk position for many growers where aphid numbers are down this season, there is the flexibility to reduce Hallmark Zeon application rates down to as low as 25 ml/ha.
"In medium to higher risk situations, where crops were earlier to emerge or aphid populations are continuing to build, rates should be increased to 35 or 45 ml/ha accordingly," reports Mr Hamilton.
He highlights that even at the lower rate, the fast knockdown of Hallmark Zeon can eliminate virus carrying aphids well before the half hour feeding required to transmit the virus; the higher rate gives greater persistence and stronger repellency to deter further aphid migration into the crop.
"For a cost of well under £2 per hectare growers can protect against BYDV yield losses that can exceed 30% in winter wheat and over 50% in barley crops," adds Mr Hamilton. "Trials have consistently shown that, even where an insecticidal seed treatment has been used, an October or November application of Hallmark Zeon will significantly reduce virus infection where expected aphid feeding activity continues into late autumn."
Caption: Cereal growers must be on the lookout for Bird Cherry Aphid populations that will continue feeding on crops and transmitting BYDV well into the autumn in mild conditions.
 |
Although populations of the Bird Cherry Aphid and Grain Aphid - which pose the greatest threat of transmitting the virus - have hitherto been relatively low, results of the latest national aphid monitoring surveys revealed a 40% increase in numbers of these two key aphid species caught over recent weeks on comparative sites (to 7 October).
"The risk of BYDV infection appears to be shifting ever later; cereal crops emerging before the second week of October - which could be as high as 60% in the highest risk areas - must now be considered as most susceptible to BYDV infection," warns Syngenta Technical Manager, Iain Hamilton. "The earlier crops are infected, the higher the severity of disease will be and the greater the yield loss."
Where mild conditions continue, there is also the chance for secondary infection. Aphids feeding on infected crops pick up disease and perpetuate its spread across the field and to surrounding crops right through the autumn and early winter, he adds.
"Growers need to weigh up the risk based on the timing of the crop emergence and the historic legacy of BYDV on their farm, allied to the current level of aphid activity," he advises. With a lower risk position for many growers where aphid numbers are down this season, there is the flexibility to reduce Hallmark Zeon application rates down to as low as 25 ml/ha.
"In medium to higher risk situations, where crops were earlier to emerge or aphid populations are continuing to build, rates should be increased to 35 or 45 ml/ha accordingly," reports Mr Hamilton.
He highlights that even at the lower rate, the fast knockdown of Hallmark Zeon can eliminate virus carrying aphids well before the half hour feeding required to transmit the virus; the higher rate gives greater persistence and stronger repellency to deter further aphid migration into the crop.
"For a cost of well under £2 per hectare growers can protect against BYDV yield losses that can exceed 30% in winter wheat and over 50% in barley crops," adds Mr Hamilton. "Trials have consistently shown that, even where an insecticidal seed treatment has been used, an October or November application of Hallmark Zeon will significantly reduce virus infection where expected aphid feeding activity continues into late autumn."
Caption: Cereal growers must be on the lookout for Bird Cherry Aphid populations that will continue feeding on crops and transmitting BYDV well into the autumn in mild conditions.
No Comments
Nobody has posted any comments on this story.
|
Farming items for Sale
|
Zetor 117-41 - Peterborough(GBP 26731)
CLAAS Ares 567 ATZ - Launceston(GBP 24500)
AXIAL FLOW 2366 - market rasen
(Price on Application)
(Price on Application)
Massey Ferguson - 7480 - Carnforth
(Price on Application)
(Price on Application)
1995 Massey Ferguson 362 4wd - Ballyclare(GBP 10750)
Related News
Warm autumn increases BYDV risk - 05 Oct 2011Early drilled crops and the continuing mild weather conditions will mean that this will be a high risk year for Barley Yellow Dwarf Virus (BYDV) in wi...
High autumn temperatures lead to BYDV threat - 21 Oct 2011With high autumn temperatures encouraging considerable aphid activity recently, a post-emergence pyrethroid spray to protect against aphid-transmitted...
More aphids threaten virus spread in seed potatoes - 01 May 2008Potato growers need to be on the lookout for a wider range of aphid species to avoid spread of virus in seed crops this season, warns SAC Entomologist...
High risk of BYDV in early drilled winter barley and winter wheat - 23 Sep 2009Winter barley and winter wheat growers should be expecting a high risk season for BYDV, linked to the warm climatic conditions this summer, the many e...
Rising aphid numbers increase risk for peas and potatoes - 22 Jun 2010A period of warm, dry weather has seen aphid numbers on the rise and migrating into susceptible crops. Reporting on the Syngenta Specialist Crops Comm...
Rising aphid numbers pose risk to peas and potatoes - 25 Jun 2010Aphid numbers are rising and numbers could rocket in the warm, settled weather. Early summer pest invasion in pea crops can cause yield-robbing physic...
Farmers warned: Autumn calves at high risk of coccidiosis - 04 Sep 2007Cattle farmers are warned to be on their guard against coccidiosis in their calves this autumn. Sub-clinical coccidiosis is often an ’invisible...
Farms at risk of bird flu spread - 24 Oct 2007LONDON (Reuters) - Controls will probably prevent the large-scale spread of bird flu from one farm to another in Britain but there is still a signific...
British farms at risk of bird flu spread - 24 Oct 2007LONDON (Reuters) - Controls will probably prevent the large-scale spread of bird flu from one farm to another in Britain but there is still a signific...
Variety rotation the best solution to spread phoma risk - 22 Apr 2010For growers in areas of the UK where phoma infection poses a significant threat to rapeseed yields, choosing a variety according to its stem canker di...
