Following record wheat yields experienced in the High Plains last year, 2008 was a disappointment, said a Texas AgriLife Extension Service expert.
Throughout the Panhandle, many dryland, and even a few of the irrigated fields, were not harvested due to drought and virus infection, said Dr. Brent Bean, AgriLife Extension agronomist.
The year was marked by less than 5.5 inches of precipitation from September through June in some places, Bean said. Additionally, wheat virus infections of both dryland and irrigated fields were worse than they have been in several years.
The best wheat yields were generally found in the northeast portion of the Panhandle where more timely precipitation was received, he said.
Planting date also seemed to make more of a difference than usual, Bean said. Wheat planted just a couple of weeks later than optimum (around Oct. 4) did not yield as well, especially if planted no-till behind corn or cotton.
Some wheat root rot was also observed in the fall and led to poor establishment in some fields, he said. This was likely due to the previous wet spring and summer that increased soil fungi activity.
Although there were some very good irrigated yields reported, overall they were a disappointment, Bean said.
“Although we did not get especially cold during the spring, we did have just enough freezing weather just prior to heading to cause some sterile heads, further contributing to lower yields,” he said.
The four viruses that infected wheat this past year were: barley yellow dwarf, wheat streak mosaic virus, High Plains disease and the recently identified Triticum mosaic virus, Bean said.
Barley yellow dwarf is transmitted by aphids (greenbug, Russian wheat aphid, others) and generally shows up as yellow stunted plants in spots in a field, he said. The virus is left in the infected plants even if the aphids are no longer present, generally causing plants to be stunted and yellow.
The other three viruses are transmitted by the wheat curl mite, Bean said. The symptoms expressed by these three viruses are very similar, making them very hard to distinguish in the field from each other. Many times the same plants will be infected with two and even all three of the viruses. Control of these viruses is similar, primarily controlling volunteer wheat two to three weeks prior to planting, he said. For a discussion on wheat streak http://varietytesting.tamu.edu/wheat/docs/e337wheatstreakmosiacvirus-2.pdf.