2008 Ag Alert Issue 2

Howdy!!!

It is hard to believe that spring is already here, considering it has been a year. We are trying a new format this year, with our ag alerts. I will be on the radio at approximately 1:35 pm on Wednesday’s with the version of our yearly ag alert. In hopes of reaching more producers, throughout the region, we will try this as postage has been going up and gone up again. You are still able to get a hard copy with a $10.00 subscription fee but will be available at your local elevators, radio and email free of charge. Planting has been moving along very nicely with wheat in the 85-90 percent completed, barley in the same range and corn in 70 percent range. Canola is all over the board with some waiting and others finishing last week. Soybeans are starting to get planted around the county. Moisture conditions are favorable for all of us but conditions just to our immediate west are much different.

REPORTS OF EARLY SEASON CUTWORMS
Cutworms have been reported in winter wheat in the southwestern region of North Dakota and central and western South Dakota, and in lentils in east central Montana. Most of the cutworm species being reported are Army cutworms and pale western cutworms. Maps of Army cutworm and pale western cutworm forecast can be found on the “Western Region Cutworm Risk Warning” website of Montana State University:
http://cutworm.org/
North Dakota is at low risk for army cutworm and at low to medium risk for pale western cutworm (see maps). The medium risk area for pale western cutworm is located in the northwestern corner of North Dakota.

Cutworms become active when soil temperatures are above 40F. With the statewide cool soil temperatures in May, cutworms will develop slower and this could result in a prolonged feeding period this year. Cutworms injury plants by chewing and/or cutting the plant in the early stages of crop development (seedling stage = most susceptible). Generally, cutworms destroy more of the plant then they eat. Their numbers vary greatly from year to year and when numerous may destroy 50-75% of a crop! Cutworms feed at night and hide in soil during the day. Since there are early and late season cutworms, feeding activity usually extends from May through the end of June.

The key to successful cutworm control is early detection and knowing your plant population. Field scouts should look for cut or wilted plants, and dig around underneath freshly cut plants to find cutworms in the soil. A flashlight at night can also be used to find the night-feeding cutworms. If the plant population is below recommended, few or no plants can be lost to cutworm feeding. The greater the plant population the more damage can be tolerated without economic yield loss. When spraying insecticides for cutworm control, applications should be made in the evening when cutworms are actively feeding. Wet soil conditions will also improve insecticide efficacy, as cutworm feed near the soil surface in these conditions.

Treatment threshold vary depending on the field crop:
Canola – 1 per square foot
Small grains – 4 to 5 cutworms per square foot
Corn – 3 to 6% of the plants cut and small larvae less than 1-inch present
Soybeans / Dry beans – 1 or more larvae per three feet of row or 20% of plants cut
Sunflower – 1 per square foot or 25-30% of plants cut
Alfalfa – 4 to 5 or more per square foot (new or thin stands – only 2/sq ft)
Lentils – 2 to 3 cutworms per square meter (Canada)
Peas – 2 to 3 cutworms per square meter (Canada)

Please see “2008 North Dakota Field Crop Insect Management Guide” for list of insecticides available on different field crops.

NOW WHAT?
Although many gritted their teeth and felt a churning in their gut when they did it, those growers that prepaid for N and P last fall made a good decision. Those that did not are now faced with N prices about double those of fall, and P prices at least triple the fall price. Feedback from the field so far has indicated that in the east and in areas with decent subsoil moisture, N and P rates for small grains and corn are similar to those in the past. In the drier areas (and it’s as dry as I have seen it in parts of the west and north since coming to NDSU in 1994) N and P rates have been reduced, and often the N application has been delayed to see if anything will come up.

As we now enter soybean, sunflower and other warm-season crop planting, a review of N and P rates with an economic slant is appropriate. Our work with wheat and corn so far has shown that N rate should be modified somewhat due to N price and crop price. In reviewing our sunflower response data, it appears that even with a doubling in sunflower price within the last year, the increase in N costs would suggest that reducing the total available N rate by at least 10% on most soils, and perhaps 20% on higher organic matter fields (greater than 3% OM) would be justified. With $1,200/ton 11-52-0, the return on P is greatly reduced from what it has been in past years.

A good yield increase in sunflower on a low testing soil is seldom more than 20%. That means that in a ton crop, a 400 lb/acre increase might be realized on a low testing soil. The return from that increase at 25 cent flowers would be about $100/acre. Our chart rates for P show a recommendation of 40 lb/acre P2O5, or about 80 lb/a 11-52-0. The cost of that application would be $48/acre plus application, which is still profitable. As the soil test P increases, the likelihood of a profitable response decreases. In past years, it would still be profitable to apply P at medium soil test levels. However, an increase of 100 lb/acre flowers ($25/acre) that one would see on a medium-testing soil from P application would not profitably support the P application (20 lb P2O5, or $24/acre + application) on a medium-testing soil. Basically, in our warmer season broadleaf crops, medium-P-testing soils do not support the profitability to apply P at current prices.

CONSIDERING A FUNGICIDE SEED TREATMENT ON SOYBEANS?
Predicting whether a seed treatment will pay on any given field, in any given year, is pretty tough to do. But we can discuss a few risk factors, which may indicate whether a seed treatment will be beneficial to you.

Temperature. When soils are cool (less than 60 F) soybeans germinate more slowly, this increases their exposure to numerous pathogens that are lurking in the soil; including Phytophthora, Pythium, Fusarium and Rhizoctonia. This year, our soils temps have generally been below average.

Water. Wet soils are more likely to provide a favorable environment for root rot pathogens. Some of these pathogens need water to cause infections and disease; some just cause more disease in a wet environment. Sometimes parts of the field appearing to have water damage may actually have been damaged by root rot pathogens. Standing water in moderation may hurt the plants some, but they also provide an extremely favorable environment for the pathogens. We have had lots of variation in rainfall statewide, but if you are in an area with wet soils, you may be at greater risk.

Disease History. If you have had stand establishment/root rot problems in the past, you may be at greater risk for root rot damage Spots in the fields with thin plant stands, or plants that appear drought stressed when there is adequate moisture and unthrifty looking could indicate symptoms of root rots.

Crop Rotations. Tight crop rotations give the pathogens an opportunity to build up in the soil, while longer crop rotations can reduce the numbers of some pathogens. High populations of plant pathogens are more likely to do damage.

Even if you don’t have all the risk factors, seed treatments may be a good option. In a two-year study done at seven different locations in ND, the average return on seed treatments across all those environments was $10-20/acre. This was assuming the price of $5.45, which is not the case anymore.

When choosing a fungicide treatment, it is best to apply a product with activity against Pythium and Phytophthora (mefenoxam or metylaxyl for example) and Fusarium and Rhizoctonia (azoxystrobin or fludioxonil for example). A good synopsis of fungicide protection against different pathogens was published by the University of Nebraska Extension Service (University of Nebraska NebFact NF411), and is available at:

For current seed treatment products in North Dakota, check the 2008 North Dakota Field Crop Fungicide Guide (PP-622) available at:

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 the 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 veterans status, or sexual orientation; and are an equal opportunity employer.

This publication will be made available in alternative formats for people with disabilities upon request, 701-662-7027

524 4th Ave NE #5, 2nd Floor Ramsey County Courthouse
Devils Lake ND 58301
701-662-7027
email - ramsey@ndsuext.nodak.edu