NORTHERN MINNESOTA GRASS SEED GROWERS

  NEWSLETTER

AUGUST 29, 2006 

GENERAL CROP CONDITION

Ryegrass
Ryegrass seeding will continue for a couple more weeks.  A shower of rain would help the emergence of this newly seeded ryegrass. 

Bluegrass
The majority of the bluegrass fields have been burned and most fields are “greening up”.  Bluegrass and weeds are growing well.  Spraying will begin this week and continue into September.          

PEST MANAGEMENT

Ryegrass
Environmental conditions the past couple of weeks have been favorable rust development, reproduction and spread of this disease.  Rust is visible on harvested ryegrass regrowth and in spring seeded ryegrass.  A small area in a spring seeded ryegrass field was sprayed with fungicides.  This trial will provide information on the effectiveness of fungicides for rust control and ryegrass plants will be evaluated this fall and again next spring to determine differences in winter survivability.

Bluegrass
Bluegrass fields burned in July could be sprayed for broadleaf weed control in the next couple of weeks.  Bluegrass fields burned in August will have herbicide applications delayed for a couple of weeks.  Fall herbicide applications should be applied to actively growing weeds.

When to spray?  This will depend upon when the field was burned, weed growth, work load, and environmental conditions.  The more time that has passed between burning and herbicide application will allow more weeds to emerge and grow.  However, the longer you wait before herbicide application the greater the probability of a killing frost.  Research has pointed out, often times, perennial weed control is better after a light frost.  A light frost can be a good thing, but a killing frost will cause death of the leaf tissue and herbicide uptake and translocation will be restricted.  When does a killing frost occur in northern Minnesota?   Median frost dates for selected towns are listed in the table below.

                                                Average Date of First Occurrence* 

City                                          32 F                 28 F                   24 F

Baudette                                 Sept 23            Oct 1               Oct 13

Crookston                               Sept 23            Oct 2               Oct 13

Hallock                                   Sept 23            Oct 2               Oct 10

Moorhead                                Sept 26            Oct 4               Oct 15

Red Lake Falls                         Sept 23           Oct 1               Oct 10

Roseau                                   Sept 18            Sept 27            Oct 6

Warroad                                  Sept 23            Sept 30            Oct 12

* Average temperature data from 1948 to 2005.

Source: DNRState Climatology Office

The temperature data in the table is an average of 57 years (1948 to 2005).  The average date for a light frost (32 F) is Sept 18 in Roseau.  All other locations have a light frost date of at least 5 days later than Roseau.   The moderate (28 F) and heavy frost (24 F), occur on average at least 3 to 5 days earlier in Roseau than other locations.

Keep in mind that this data is an average.  Some years the first frost will be earlier and others years later.  In addition, the microclimate (wood lots, shelterbelts, lakes, organic soils) can have a big impact on the first frost dates.  Looking at these average first frost dates combined with local experience will help determine when to spray broadleaf weeds in grass seed crops.

How can this data be used for timing of broadleaf weed control?  To be effective, the herbicide has to be taken up by the plant and translocated to sites of active growth.  A killing frost will interrupt this process.  The result will be incomplete weed control.  A rule of thumb would be that the herbicide should be on for at least two weeks prior to a killing frost.  The average temperature data in the table coupled with the knowledge of the microclimate in your location will help determine application timings for fall broadleaf weed control.      

The most popular choice for broadleaf weed control in bluegrass is a tank mix of dicamba and 2, 4-D. The use rates vary from ½ to 1 pint. Check with your agronomist for product and rates that have been successful in your area.

CROP MANAGEMENT

Ryegrass
Soil tests should be taken on ryegrass fields that will produce seed in 2007.  Results of field tests this summer indicate ryegrass roots were found to 34 inches in the soil profile.  Ryegrass rooting depth this deep in the soil was a surprise to many people.  With ryegrass rooting depth deeper than 34 inches in may be wise to take soil tests to at least 24 inches to determine fertility levels in the soil profile.            

Bluegrass

If bluegrass fields have not been burned that should be done as soon as possible.  Late burns can have a negative impact on seed yields.  Bluegrass has to have enough time to green up going into the winter.

Broadleaf weed spraying will begin this week and continue for several weeks.

SOYBEAN PLOT TOUR

The University of Minnesota will host a soybean plot tour near Roseau on September 6, 2006.  This evening tour will begin at 4:30.  Directions to the field:  At the junction of highway 11 and 310 (Holiday and Cenex gas stations) go north of highway 310 for approximately 2 miles.  Turn left (west) on county road 16 and travel for 2 miles.  Turn right (north) on a gravel road for approximately 1/8 of a mile and soybean plot is on the east side of the road.   

Topics to be discussed at this tour include: soybean varieties, iron chlorosis, soybean insects and diseases.  Mark your calendar and plan to attend this soybean plot tour.

Next newsletter scheduled to be released on September 5, 2006.