NDSU Extension - Grand Forks County

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Volume 33, Issue 04 | July 2nd, 2020

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INSECTS, TRAPS AND ACTION THRESHOLDSAphid

Low densities of aphid pressure has been observed in Grand Forks County, but with changes in pressures systems, strong storms, and southern winds, continue to be on the lookout for soybean aphids, sunflower moth and thistle caterpillars that may have hitched a ride north. Strong storms can also dislodge existing aphid pressure. I have observed a lot of ladybugs which help control aphid populations along with other predatory insects. The critical growth stages for making most soybean aphid treatment decisions in North Dakota appear to be the late vegetative to early reproductive stages (Vn to R3). Assessing aphid populations at this time is critical. Typically aphid treatments occur from mid-July to mid-August. Only spray for aphids when the economic threshold has been met:

Economic Threshold for Soybean Aphid:

  • R1 (beginning of flowering) to R5 (beginning seed) = 250 aphids/plant when populations are  actively increasing in 80% of field
  • R6 (full seed) = No treatment necessary. Research trials throughout the north central states have not demonstrated a yield benefit to treating soybean for soybean aphid management at the R6 and later stages.

Last week I addressed grasshoppers. Grasshoppers nymphs are continuing to grow, reaching 2nd or 3rd instar.  The bigger they get, the more plant they will consume. Continue to monitor, and control when pressure reaches the action threshold of 50-75/sq. yard in field margins, or 30-45/sq yard within the field.

European Corn Borer traps in Grand Forks County did not have any moths present last week, but Insect Degree Days is forecasting emergence as not far off. Grand Forks NDAWN has accumulated 855 IDD. The Degree Day models indicates 10% of moths are emerged at 911 degree days. See this week’s Crop and Pest Report for full story.

Armyworms have also been reported this season in different areas of the state. If you find armyworms, I would be interested in hearing about these infestations.

Seeing these or other pests? Shoot me an email!

Source: NDSU Insect Control Guide (2020)

 

DISEASE FORECASTING MODELS

WHITE MOLD

Dry edible beans, sunflower, and soybean fields are abundant in the county this year, and we’ve also received our fair share of high humidity and moisture. Should these conditions continue as beans near flowering, the environment may be favorable for white mold infection to occur.   There is a great white mold review in this week’s Crop and Pest Report that I encourage growers to check out.

FUSARIUM HEAD BLIGHT

From this week's Crop and Pest Report: According to the National Fusarium Risk model, risk continues to remain high for susceptible varieties that are flowering in Eastern ND (Figure 1). For moderately susceptible varieties, risk is low for most of the state. Currently, the National model and NDSU model differ in scab risk projections and I would suggest that the NDSU model is too conservative in the assessment of FHB risk. Recent rain events and higher nighttime humidity will likely increase FHB risk on susceptible varieties for several areas in the state. Continue to monitor the growth stage in small grain fields to determine the best time to apply a fungicide (if warranted). The best time to apply a fungicide in wheat is at early flowering and up to seven days after the start of flowering (Figure 2). In barley, the best time to apply is at full-head and up to seven days after full-head (Figure 3).

Andrew Friskop

Extension Plant Pathology, Cereal Crops

 

 

 

 

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SUBSCRIBE TO WEEKLY CROP AND PEST REPORT

 

 

Subscribe to the weekly NDSU Crop and Pest report for timely, seasonal articles based on research and tailored to North Dakota.  You can view current and archived Crop and Pest Reports on their website, at https://www.ag.ndsu.edu/cpr/ or visit the Facebook page @ndsuextcpr.  Subscribe to the Crop and Pest report via the website to receive weekly pdf’s via your e-mail.

 

FLOOD INFORMATION FOR HOMES, FARMS, FAMILIESRain Event

A major rainfall event in parts of the county on Tuesday afternoon/evening has left culverts and drains unable to temporarily keep up. Water has backed up in ditches, yards, fields, and residential areas.  Some areas will recede faster than others. The NDSU Extension Flood webpage has a number of resources available for flood recovery, and preparation:

- Home and House; before, during, and after the flood

- Family and Children including financial issues, resilience,  keeping children, pets and yourself safe.

- Farm and Ranch, including property, vehicles, crops and livestock

- Information in other languages

 

COVER CROPS ON PP ACRES

Wet conditions this spring prevented a lot of the low ground/field edges from being planted; many of these areas are enrolled in prevented plant. With recent epic rain event, many of these areas are underwater again, or fully saturated as culverts and drainage ditches struggle to keep up. Fields/pieces enrolled in PP, do not have to take a crop loss on this (again) flooded ground. The years when it is dry in the spring, do these areas get planted only to suffer great loss, with inputs running (literally) down the drain? Are there ways to re-think how we manage low ground, especially along field edges? This will vary from field to field and how often one gets a respectable crop on low areas. But we know there are years when nutrient load and soil erosion are high, costing producers their valuable resources and $$. A planted, flooded crop has even higher cost. A cost analysis of these low areas can help lead future management decisions.

Getting a cover crop on prevented plant acres is becoming more and more important to help these fields dry out and reduce weed pressure.  Not planting a cover crop will increase the chances of these fields/areas staying in prevented plant again next year. To use up excess moisture, include crops cereals to help wick up ground water.  Consider including in your mix:

- 2lbs Sorghum-Sudangrass. High water use. If you are worried about the biomass, 'Piper' is a shorter variety. 

- 1-2lbs Sunflower, or another deep rooted crop.

- 20-45lbs small grain, depending on the mix

- Can throw a legume in to help with residue if biomass is becoming a concern

- If using a brassica such as radish or turnip, do not exceed 2lbs brassicas total in the mix.

If you are concerned about hilltops drying out or cost of mix, focus on splitting the field at planting, and plant moisture loving plants in the lower areas like cereal rye, and let it overwinter to keep wicking moisture through next spring, and plants that use less water on the high-ground (or lessen rate). Great tip learned from Abbey Wick!

Questions? Call or Email me, or visit the Prevented Plant Website.

EVENTS THIS SUMMER

  • Youth Land Judging/Soil Management Workouts; Thursday afternoons in Larimore. Contact MaKayla Fleming for more information or to sign up.

 ENJOY THE HOLIDAY WEEKEND!

 

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