ND SMALL GRAIN PEST SURVEY

SMALL GRAIN DISEASE SURVEY, 2001
Marcia McMullen, Phil Glogoza, Roger Ashley, Greg Endres, Jan Knodel,
NDSU Extension Service, Plant Pathology Dept., Entomology Dept. Dickinson REC, Carrington REC, and North Central REC, respectively 

Purpose: The purpose of the small grain disease survey was to determine the occurrence, distribution, and severity of leaf and head diseases in North Dakota's wheat and barley crops in 2001. Additional observations were made of insect pests such as grasshoppers, grain aphids, cereal leaf beetle and wheat stem maggot.

Methods: NDSU IPM field scouts were hired, with supervision and direction from the Fargo Experiment Station and from research extension centers at Dickinson, Minot and Carrington. Field scouts were Nathan Carlson, Matthew Gregoire, Jeanna Jambor, Kelly Novak, Jerry Schneider, and Holly Semler. Fields were surveyed from early leaf stages through soft dough stage of kernel development. Field scouts recorded district, county, field location, crop, growth stage, previous crop, and incidence and severity of major pests. Data was recorded on hand held computers and transferred to the research extension centers and the Fargo station. Data was summarized and analyzed and weekly reports were provided to county extension staff and to the public via the NDSU Crop and Pest Report.

Results: Approximately 1500 spring wheat, durum, barley and oat fields were surveyed in 2001, with the majority (958 or 64%) hard red spring wheat fields. Of the other crops, 249 durum, 196 barley, 25 winter wheat and 30 oat fields also were surveyed.
Leaf rust was detected in 22% of the 958 spring wheat fields surveyed. The most frequent detections were in the south central and central areas of North Dakota. The average severity in infected fields was 8.5%; the average severity across all fields was 1.9%. Leaf rust was not detected until July 5, in LaMoure and Dickey counties. Leaf rust did not have significant impact on yields in 2001, except perhaps for a few late planted fields of susceptible varieties.
Tan spot was found frequently in spring wheat and durum wheat and was the most common disease observed prior to heading stages. For crops surveyed past heading, tan spot was found in 54.7% of the spring wheats and 63.1% of the durum fields. Tan spot severity on flag leaves of headed crops averaged 6.9% in spring wheat and 7.5% in durum wheat. (See table).
Septoria leaf blotch was observed most frequently after head emergence. Of fields surveyed past flowering stage, 78% of the spring wheat fields had Septoria symptoms, 85.3% of the durum, and 74.3% of the barley fields had symptoms. Average severity on the flag leaf in infected spring wheat fields was 10.9%, in durum wheats was 18.9%, and in barley 6.0%. (See
table).

Scab (Fusarium head blight) was observed in 70% of both spring wheat and durum wheat fields past the flowering stage, and in 42.1% of barley fields. Average severity of scab in spring wheats was 4.0% (range 0.1 - 34.2%), average severity of scab in durum wheats was 7.2% (range 0.1 - 80%), and in barley average severity was less than 1% (range 0.1-2.3%). The most severe scab was found in the north central and northwest districts and primarily in durum. (See table and Scab map).

Other diseases: Diseases such as flag smut and dwarf bunt were NOT observed in the survey. The virus diseases, wheat streak mosaic and barley yellow dwarf, were very infrequent, as were black chaff and ergot. Loose smut was observed in 43% of the headed barley fields, and severity ranged from 2 - 14%. Loose smut was found in 29.9% of spring wheat fields, and severity ranged from 2 - 34%, with 2-4% most common.

SCAB
Crops were surveyed for scab from watery-ripe stage (Zadoks growth stage 71) to mid-dough; information below is on these surveyed fields

TAN SPOT and SEPTORIA IN FIELDS PAST THE KERNEL WATERY RIPE STAGE:

Top Of Page

ND IPM Homepage