Traill County Ag Alert Newsletter

Traill County Ag Alert Newsletter

June 20, 2008

RAINFALL & GROWING DEGREE DAYS (GDD)

Location                               Mayville           Hillsboro          Galesburg
Corn GDD                                462                   474                   464
Compared to 2007                   -180                 -176                  -167
Wheat GDD                             1137                 1143                 1153
Compared to 2007                   -285                 -291                  -252
Rainfall since June 1                  2.61 inch           3.81 inch           3.79 inch

CANADA THISTLE ON CRP PLOT TOUR – JUNE 25
All are invited to attend a plot tour to view and discuss weed management on CRP land. University and industry speakers will provide demonstrations and discussions on Canada Thistle Management, Brush Control, CRP Re-Enrollment and other topics important to CRP land managers. The plot tour is 5 miles north of Ada on Highway 9, turn East on County Road 19, travel 4 miles and turn north on 300^th Street for 1.25 miles on Don Andersen Farm. For more information contact: Carlyle Holen @ 218-281-8691 or Jolene Pedersen @ 218-281-8027

CUTWORM ACTIVITY CONTINUES!
Field reports indicate that cutworms are still a problem especially in some of the late seeded row crops. Early season cutworms, like dingy cutworms, should be completing their life cycle and starting to pupate. Check the size of the cutworm larvae to see if it is mature (about >1 inch). If young cutworm larvae (<½ inch) and newly injured plants are not present, there would be no economic benefit to treating the field with an insecticide. Some of the late-season cutworms that may be active now include red-backed cutworm, darksided cutworm and variegated cutworm. This year scouting is a must until early July with the late season.

SUGARBEET ROOT MAGGOT: MAJOR FLY ACTIVITY SURGE LIKELY OVER WEEKEND
Sugarbeet root maggot (SBRM) fly counts from sticky stakes have remained low throughout the Red River Valley (RRV) during the past several days, but this week’s more “normal” June weather should quickly change that scenario. Significant increases in degree-day (DD) accumulations have occurred during the past few days, so a dramatic, sharp increase in root maggot fly activity is expected.

Fly activity is expected to peak around June 20 or 21. Warm (around 80 F), dry weather and calm to low-wind conditions are most conducive to fly activity, so rainy or windy weather could cause slight delays in the actual peak date. *Peak fly activity in beets is most likely on the first calm or light-wind and 80 F day, after the required 600 air DD are accumulated.

Fields in high-risk areas may require the application of a postemergence rescue insecticide, especially if a low or moderate rate of a planting-time insecticide was used on the crop. Rescue insecticide applications are also recommended if a hotspot of SBRM fly activity erupts in a given field. Liquid insecticides are going to be the best option at this time because most infestations are so close to peaking. Postemergence liquid insecticides should be applied within 3 days of the expected peak, and applications made before peak work best. This will provide control of both adults and larvae.

WHAT ABOUT TANKMIXING MY INSECTICIDE WITH AN HERBICIDE?
NDSU research indicates that crop safety and effective weed and insect control can be achieved by tankmixing a microrate herbicide combination with an insecticide for SBRM control. Insecticides tested in this scenario have included Lorsban 4E and Mustang Max. FMC Corporation has endorsed the use of Mustang Max/glyphosate mixtures with a 2(ee) recommendation. However, it must be noted that glyphosate labels do NOT endorse glyphosate/insecticide combinations for use in sugarbeet. Therefore, growers choosing to mix their preferred SBRM foliar insecticide with glyphosate for use in sugarbeet assume all liability for any potential control failures or crop losses associated with such applications.

For more guidance on the sugarbeet root maggot forecast or insect control strategies, consult the “Insect Control” section of the 2008 Sugarbeet Production Guide or the “Sugarbeet Insects” section of 2008 Field Crop Insect Management Recommendations. Online versions of these publications are located at: www.sbreb.org/Production/production.htm and www.ext.nodak.edu/extpubs/plantsci/pests/e1143w1.htm

WHEAT LEAF RUST DETECTED
Trace levels of wheat leaf rust has been found in two spring wheat fields in Richland County on June 16. These fields were in the jointing stage, and only one or two pustules were found. This detection is about 10 days later than when wheat leaf rust was first reported in 2007. Leaf rust levels have been reported to be high on susceptible cultivars of winter wheat in states to our south this year.

FUNGAL LEAF SPOTS FOUND IN LAST WEEK’S NDSU IPM SURVEY
During the week, spring wheat was generally in the tillering stage, with a few fields jointing. Winter wheat was jointing to early heading, and barley was tillering to jointing.

Tan spot was the only wheat disease observed last week, with 1/3 of all wheat fields surveyed showing infection. The highest incidence and severity occurred in fields planted into wheat stubble. Other wheat or barley diseases were not observed last week, and neither were insects, except for a very few grasshoppers in field margins. Field scouts in the southwest did report seeing leafhoppers in the fields.

NDSU EXTENSION PLANT PATHOLOGY WEB SITE
The NDSU Extension Plant Pathology web site has recently been updated to include a link to the compilation of NDSU sponsored 2007 small grain fungicide trials. The site also has links to three new plant pathology publications, one on Ascochyta in chickpea, one on Black leg in canola, and one on rust diseases of wheat. The NDSU Extension Plant Pathology web site is found at: http://www.ag.ndsu.nodak.edu/extplantpath/

COOL SOILS/RECENT RAINS MAY ENCOURAGE ROOT ROT OF SOME ROW CROPS
Despite being very dry earlier this spring, we may begin seeing the effect of root rots in some row crops. Cooler than average soil temperatures often mean seeds stay in the ground longer, increasing their exposure to root rotting pathogens present in the soil. Last week’s rain may give some root rot pathogens a foothold on some broadleaf crops, particularly those recently planted (edible beans and soybeans for example). Although there is not much that can be done to manage root rots after planting, the observation of suspected root rot in a field (poor stand, young plants yellowing/wilting/dying) may influence management decisions this year and next. If you see some suspicious patches in the field, take note for the future, it may be root rot diseases.

MISS ROUNDUP®, MICRONUTRIENTS, AND THEIR UNHAPPY MARRIAGE
A number of studies have shown that micronutrient additions to glyphosate can reduce weed control. Even applications of micronutrients a few days before glyphosate application can reduce weed control. Reductions in weed control may not always happen, and additions of extra ammonium sulfate may help to reduce the reductions.

In trials near Walcott, ND in 2002, application of an iron chelate increased the phytotoxicity of three postemergence broadleaf herbicides on soybeans and reduced soybean yield an average of 4 bu/acre. In Michigan research, in micronutrient and Roundup® tankmixes, lambsquarter control was reduced 50% with iron. Adding more ammonium sulfate, or increasing Roundup® rate increased control, but reduction in efficacy was still recorded. In Virginia, manganese tank mixes reduced control of lambsquarter, smooth pigweed and large crabgrass.

Roundup® is a product licensed and registered by Monsanto Corporation and neither Dr. Franzen nor North Dakota State University make any promotion of its use over similar products.

IMPACT HERBICIDE - REDUCED CROP ROTATION RESTRICTIONS
The Impact herbicide label now includes the reduced use rate of 0.5 oz with a 9-month plant back to soybeans as opposed to the 3/4 fl oz rate which would require an 18 month restriction on soybeans. The new Impact label also adds four new weeds: green foxtail (in addition to yellow foxtail), dandelion, powell amaranth (similar to redroot pigweed and well established in ND), and marestail.

NEW HERBICIDE FOR SOYBEAN
Authority Assist is a premix for preemergence broadleaf weed control in soybean. The ingredients are sulfentrazone (Spartan) and imazethapyr (Pursuit). Authority Assist has rate recommendations at full rates of 6 to 12 fl oz/a depending on soil type and organic matter, and at reduced rates of 4 to 6 fl oz/a. The reduced rates are intended as a foundation treatment to suppress early season weeds before a glyphosate application in Roundup Ready soybeans. The 6 fl oz/a rate provides the equivalent of 6 fl oz/a Spartan and 2 fl oz/a Pursuit.

With this premix, control or suppression of lambsquarters, nightshade, pigweed, smartweed, velvetleaf, and waterhemp should be expected along with suppression of foxtails. Common and giant ragweed are weeds that may not be suppressed well. Because Authority Assist contains imazethapyr, certain rotational crops are limited. Rotational intervals include wheat at 4 months, barley 9.5 months; field corn, and peas, at 10 months; alfalfa at 12 months; oats and sweet corn at 18 months; potatoes at 26 months.

AXIAL XL HERBICIDE LABEL CHANGES

• Do not graze livestock or harvest forage for hay from treated wheat and barley for a minimum of 30 days following application.
• Do not harvest grain for 60 days following application.
• Do not apply both Discover and Axial products to the same crop in the same season.
• Wheat and barley straw may be fed to livestock 60 days after application.

PERMIT HERBICIDE REGISTERED IN DRYBEANS
2007 was a banner year for common ragweed and it was especially a problem in broadleaf row crops, including dry beans. Permit controls most large-seeded broadleaf weeds including cocklebur, marshelder, wild mustard, and ragweed species. Permit was developed as a POST corn herbicide. Gowan has also expanded the label to include use on additional crops, including dry edible beans. Permit is labeled for PPI and PRE use in dry beans at up to 0.67 oz product/A. NDSU has a limited database on PRE weed control.

A logical program for common ragweed control in dry beans would be Permit PRE followed by Reflex POST if escapes occur. These programs would give different modes of action, which is good because ragweed resistance to Permit (ALS) has been documented.

NDSU Extension Service, North Dakota State University of Agriculture and Applied Science, and U.S. Department of Agriculture cooperating, Duane Hauck, Director, Fargo, North Dakota. Distributed in furtherance of Acts of Congress of May 8 and June 30, 1914. We offer our programs and facilities to all persons regardless of race, color, national origin, religion, sex, handicap, age, Vietnam era veteran status, or sexual orientation; and are an equal opportunity employer

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Hillsboro, ND 58045

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