Friday, April 05, 2013

Field Scouting Report for April 3: Cold Related Problems in Wheat Fading; Time to Scout for Wheat Curl Mites

Contact: Jill Scheidt, agronomy specialist
Tel: (417) 682-3579

Jill Scheidt, agronomy specialist with University of Missouri Extension in Barton County, scouted fields in Barton County on April 1 and noted several items of concern.

According to Scheidt, the temporary phosphorus deficiency, identified by a uniform purpling of the leaf, is fading as temperatures rise in wheat.

“Powdery mildew is also fading and is unlikely to be a threat that requires treatment at the earlier stages of growth. Powdery mildew becomes a concern when the flag leaf is present in wheat,” said Scheidt.

No aphids were seen; aphids are active when temperatures reach 60 degrees. If temperatures are below 60 degrees, aphids should be scouted for at soil level in the crown of the wheat.

Bird cherry oat aphids, identified by the red ring around its rear, should be scouted for in wheat from now until wheat begins to mature. Threshold levels are 6 aphids/foot. A rate of 3.2 oz/A Warrior or 3.6 oz/A Mustang Max is recommended to control aphids.

“Do not mistake aphids with white flies; white flies are white insects with wings which also suck sap from leaves but are unlikely to be a pest threat in wheat. Aphids are small, green insects without wings; that tend to hop on leaves,” said Scheidt.

Wheat curl mite should also be scouted for in wheat. White curl mites are tiny, white, cigar-shaped mites, about 1/100 inch long and require a magnifying glass to be seen. White curl mites could pose a threat if winter temperatures were mild. White curl mites vector wheat streak mosaic virus.

“Look for mites on stunted plants, curled leaves or leaf streak injury plants. There is no threshold level for white curl mites. Controlling volunteer wheat and border grasses and planting resistant varieties are the best practices to minimize threat,” said Scheidt.

The weekly field scouting report is sponsored by University of Missouri Extension and Barton County Extension.

For more information on this scouting report, or to learn how you can receive it a week earlier by telephone, contact the MU Extension Center in Barton County at (417) 682-3579.


Post a Comment

Let us know how you have been helped by this article or what you have learned from this story.

<< Home