The damage is caused by two different viruses, the wheat streak mosaic and the High Plains, he said. Both are transmitted by the wheat curl mite (Aceria tosichella), common to the central plains of the United States.
"In the past few weeks, farmers, Texas Cooperative Extension specialists, county agents, crop consultants and insurance agents have reported some wheat fields were all but dead," said Rush. Diagnosis can be tricky, he added, since one or more viruses might be present. Wheat streak mosaic can occur any place wheat grows.
Mark Harrison, independent crop consultant and agronomist working in Dallam and Hartley counties and Union County, N.M., agreed.
"In the last month or so, we have seen WSMV mostly with some HPV but not much. Usually the wheat streak will show up in the spring as farmers start fertilizing and irrigating, which increases the chances for infection," Harrison said
"One grower reported most of his irrigated crop circle was dying down rapidly, and that's a red flag the mite has been spreading the viruses in early planted irrigated fields."
In addition, several client farmers were just plowing up damaged fields of 200 to 700 acres. "With fuel costs what they are right now, trying to salvage severely damaged crops would not be cost effective," Harrison said.
This year, Rush tested samples from enough locations to verify his suspicions.
"Wheat streak is wide spread now, but the really bad fields, the ones that are dying, have usually been infected with both viruses that multiply only on living plants," he said.
Wheat is an excellent host for wheat streak mosaic virus; other grass species can host bo
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Contact: Pam Dillard
p-dillard@tamu.edu
806-677-5600
Texas A&M University - Agricultural Communications
25-May-2004