Friday, March 27, 2015

Barley Yellow Dwarf Epidemic

Our winter wheat and winter barley crops have broken dormancy very early - I’d say we are 3 - 4 weeks ahead of “average" and almost all of our spring wheat is planted.

About 3 weeks ago, we started having symptoms of BYD showing in winter cereal fields. Two times in the last two weeks I have taken a tour through the southern part of the state. In most areas, 85-95% of our winter wheat fields are showing 95-100% incidence. Some are severe, and growers are removing (spraying and plowing) some of these fields and replanting spring grain or dry beans. Growth stages are tillering to jointing.


Contributing factors include unusual rains last August, high populations of aphids in the fall (especially in the corn that was green chopped), a long fall, and we have had one of the warmest winters / earliest springs on record. Full rates of insecticidal seed treatments have been ineffective due to a long warm fall and high aphid populations. 

Dr. Arash Rashed and I have been wiring very hard to obtain ELISA and qPCR confirmation before sending out too many alerts to the growers. I did send an alert March 16th, but didn’t want to do another until we had proof positive - double - that what we were seeing was totally accurate. It is so widespread that even I was questioning myself. It is EVERYWHERE - from Parma to Idaho Falls and Ririe.

We also have severe drought conditions, which makes mitigation more difficult and damage potentially more severe. Many growers will not be able to apply irrigation for another 1-3 weeks.

We have virus in wheat, barley, timothy and field borders, roadsides, ditch banks, and farmyard grasses.I expect greater than 30% losses, in some fields greater than 60% losses. Winter malt barley fields will not make malt. Many winter wheat fields will have to go for feed.

Please use the University of Idaho CIS bulletin as a reference: http://www.cals.uidaho.edu/edcomm/pdf/CIS/CIS1210.pdf


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