FROM AROUND THE STATE
ISSUE 16 August 23, 2001
SUNFLOWER INSECT UPDATE
Dr. Larry Charlet, USDA ARS Sunflower Entomologist, and myself recently conducted a mini-survey of sunflower insects in the North Central Region. Counties surveyed include: Mountrail, Ward, Renville, Bottineau, and McHenry Counties. Most of the sunflower fields were in the mid to late flowering stages. The most common insect was the Banded sunflower moth, which was very easy to find especially in the edge of fields.
Most head damage was confined to <10% of the head. Fortunately, an endoparasitoid, Glypta prognatha (Ichneumonid wasp), of the larvae of Banded sunflower moth was very abundant, and could be observed probing with its ovipositor into the heads of sunflower. The literature indicates that this parasite plays an important role in keeping pest populations below levels causing economic losses. Red sunflower seed weevils were also found at low levels or below economic threshold levels for both oil and confection sunflowers. Lygus bugs were common in fields, but were more difficult to find due to its secluded behavior and cryptic color. Research is being conducted on economic threshold levels of Lygus bug in confection sunflowers. Incidental (or non-damaging) insects that were observed at very low levels include: sunflower beetles, Aster leafhoppers, grasshoppers, thistle caterpillars, headclipping weevil (only 1), Apion stem weevil (only 1), and sunflower moths.
Janet J. Knodel
Area Extension Specialist Crop Protection
North Central Research and Extension Center
Small grain harvest is well underway. Barley yields from 50 to 80 bushels per acre are common. Test weights from 44 to 47 lbs per bu and percent plump from 60 to 80. DON contents from 1.5 to 9 is limiting sale as malt barley. HRS harvest is 50 percent complete along and south of Hwy 2 and in the Red River valley but just getting a good start in northern counties. Some growers have finished wheat harvest. Scab severity levels in HRS vary from traces to 20% in some varieties and fields in the northern counties. Durum planted after May 15 generally has been hard hit by scab with severity levels of 50% or higher commonly observed. Preliminary looks at fungicide performance indicates good leaf disease suppression and 60-70 percent reduction in scab.
White mold is common in dry beans. Some flax plots in the variety trial at Langdon were heavily infected with white mold. Trace amounts are being observed white mold in commercial flax fields where extreme lodging occurred. Sunflower to date has low levels of basal stem rot. Sunflower midge damage is very light this year and the crop potential is excellent to date. Canola swathing is being completed this week with some of the crop harvested. White mold infection is about average and much less than last year. The infections generally occurred later bloom stages and seems to have effected the branches more than the main stem. Yield potential appears to be average for most of the Canola crop.
In general, the durum crop and oat varieties not resistant to rust will be disappointing but HRS, barley, flax, canola, and drybeans not severely affected by white mold have average to good yield potential. Corn and soybean crops have excellent growth and yield potential if the frost holds off until September 20th. Dry harvest weather is a continuing need right now.
Area Extension Specialist/Cropping Systems
Devils Lake, ND
During the past 2 weeks (August 8-21), recorded rainfall at NDAWN sites in south-central North Dakota ranged from 0 inches at Edgeley to 1.2 inches at Oakes. Most areas received one-half inch or less of rain during this period. Several counties including Dickey, Eddy, LaMoure and Wells received heavy rain, wind, or hail last week. Estimates of daily water usage from NDAWN for corn emerged May 15, soybean emerged May 29, and sunflower emerged June 5 ranged from 0.18 to 0.30 inches on August 21. Additional rain would be welcome for warm-season crops south of I-94.
Small grain harvest south of I-94 is complete or will likely be completed by August 25. Wheat yield and quality appear good, with yields being reported of up to 60-70 bushels/acre. North of I-94, small grain harvest is about 50% complete. Early-planted wheat, if not lodged, is yielding well. Lodged or late-planted small grain generally have disappointing yield and quality. Canola harvest is about 25% complete. Flax swathing is underway and hay harvest continues. The regionís corn, soybean, and sunflower generally are in good to excellent condition. Post-harvest tillage of small grain fields is a common activity in southern counties.
Corn leaf aphid can be found in corn, but insecticide use is not recommended at this time of corn development. Insecticide application for control of seed weevil and lygus bug has been common in the regionís confection sunflower. Reports of significant lodging of sunflower have been reported in Barnes County.
The NDSU Carrington Research Extension Centerís 2001 winter wheat variety trial consisted of 31 varieties that averaged 49.2 bushels/acre, 56.7 lb/bushel, and 12.8% protein. The highest yielding HRW varieties (57.9 to 69.0 bushels/acre) in the 2001 trial included Agassiz, Arapahoe, CDC Falcon, CDC Kestrel, CDC Raptor, Elkhorn, Morgan, Jerry, Norstar, Ransom, Roughrider, and Seward. Also, the Carrington Centerís 2001 winter rye variety trial consisted of 5 varieties and averaged 54.4 bushels/acre.
A canola disease survey was conducted by the NDSU Extension Service in 39 swathed fields in Stutsman, Eddy, Foster, Wells and Sheridan counties during August 15-21. Field incidence of sclerotinia (white mold) based on examining 40 stems/field ranged from 0 to 83%. Field incidence of sclerotinia by county: Stutsman = average of 28% and range of 0-58%, Eddy and Foster = average of 25% and range of 3-70%, Wells = average of 40% and range of 3-83%, and Sheridan = average of 38% and range of 0-73%.
Area Extension Specialist/Cropping Systems
NDSU Carrington Research Extension Center