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Small Grains Disease Update 07-18-13

The grain fill is rapidly progressing towards physiological maturity in both spring and winter wheat across the State. Actually, the first winter wheat in West Central Minnesota was reportedly harvested today. The scouts continue to predominantly fin the tanspot/Septoria complex of leaf diseases and BYDV. Incidence of leaf rust remains low while no stem or stripe rust was found to date.

This year marks the 20th anniversary of the great scab epidemic of 1993 and. Although we have made considerable progress towards controlling the disease, by now means have we eradicated or silenced the disease. Winter wheat trials in LeCenter and Crookston are showing a fair amount of FHB as do the some of the earliest spring wheat fields. It is too early to tell whether we have widespread problems this growing season but that the disease is here again this year is pretty clear.

Therefore, assess the damage caused by FHB now and prepare for harvest accordingly. If you have little to no affected spikelets 10 to 14 days after anthesis you escaped the worst and can probably harvest the way you always do. If, however, you see 10% more of the spikelets affected, you need to make sure that you: 1) increase the fan speed to attempt to remove as much of the tombstone kernels as possible, 2) store the harvested grain separately as much as possible. The idea is to reduce the DON toxin levels as much as possible in the harvested grain and quarantine grain that may have elevated levels of DON as to not contaminate otherwise sound grain from other fields/varieties.

Bruce Potter in Lamberton reported on flights of armyworm moths a few weeks back. Doug Holen confirmed armyworm damage in lodged grain earlier today in the Fergus Falls area that included leaf and head clipping. Armyworms are dark green to light brown worms that can get up to 1.5" inches in length. Scouting for armyworms requires some effort as they are largely inactive during the day. Look for the small fecal pellets on top of the soil and move debris and small clumps of soil around to find the larvae curled up underneath. A treatment to control armyworm is recommended if 4 to 5 larvae per square foot can be found across much of the field. Reduce this threshold if head clipping occurs.

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