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ISSUE 5  JUNE 3, 1999

 

WHEAT LEAF RUST DETECTED

    Dr. Jim Miller, USDA cereal rust pathologist, Fargo, reported seeing wheat leaf rust on
May 27 at Casselton. He found trace levels of leaf rust on the lower leaves of Norstar winter
wheat planted in the experimental plots at the Agronomy Seed Farm. The winter wheat was in the
jointing stage.

 

SUMMER PEST SURVEYS BEGIN

    Four individuals have been hired by the NDSU Extension Service to survey for diseases and
insect pests on crops in North Dakota. The survey will concentrate on wheat, but canola and
sunflowers also will be surveyed for some major pests. The crop scouts will cover the entire state
this year, which will provide us much needed information about the distribution, incidence and severity
of our major pest problems on these crops in the state.

    The four individuals hired to survey are:
a) Amy Dukart, from Manning, ND. Amy will be a third year student at Dickinson State University,
and just completed Dickinson’s two year Agriculture program. Amy will be working with Roger
Ashley, Area Agronomist at the Dickinson REC; b) Jerry Schneider, originally from Napoleon, ND.
Jerry currently is a middle school and high school computer instructor in Carrington. Jerry will be
working with Greg Endres, Area Agronomist at the Carrington REC; c) Brittany Sund, from Newburg,
ND. Brittany will be a senior at NDSU, majoring in Crop and Weed Science. Brittany will be working
with Jan Knodel and Kent McKay at the Minot REC; d) Jerry Ries, from Tower City, ND. Jerry is a
recent graduate of NDSU in the Crop and Weed Science program. Jerry will be working with Marcia
McMullen at the Fargo Exp. Station. Each surveyor will be responsible for scouting crops in a 11 to 15
county wide area.

    In addition to the above efforts, Jeremy Pederson, NDSU Extension Research Specialist, will
be surveying barley for diseases in 1999. He will be looking at previous crop history and its affect on
disease, and will be surveying primarily in the eastern half of ND.

 

1999 FIELD CROP FUNGICIDE GUIDE NOW AVAILABLE ON WEB

    The NDSU Extension Circular PP-622 "1999 Field Crop Fungicide Guide" is now available on the NDSU Extension Internet Web Site. The specific address is:

http://www.ext.nodak.edu/extpubs/plantsci/pests/pp622w.htm

    Art Lamey and I have also included the Section 18 products available on some crops in ‘99.

Marcia McMullen
Plant Pathologist/IPM Coordinator
mmcmulle@ndsuext.nodak.edu

 

SECTION 18 GRANTED FOR TATTOO C ON POTATO

    The Environmental Protection Agency granted a section 18 for the use of Tattoo C on potatoes for
control of late blight. Tattoo C may be applied by ground, chemigation or air at a maximum rate of
2.3 pints/A. There is a 14 day PHI (pre harvest interval). The section 18 approval indicates that
Tattoo C should be applied only in situations when registered fungicides would not provide suitable
disease control, such as when plants are actively growing and the threat of moderate to severe disease
pressure exists. Winter wheat cannot be planted within 30 days of the last application of Tattoo C. Any
crop can be planted within 4 months of the last application, so there would be no rotational considerations
for the year 2000.

    With regard to the stated section 18 comments about when to use Tatoo, I believe that it should be
used only when the plants are actively growing. This assures adequate uptake of the fungicide and
translocation to new growth, providing protection of new growth. Protection of new growth on actively
growing plants is often one of the significant challenges in disease control; the ability to protect new foliage
is a unique feature of Tattoo C. For best results, Tattoo C should be used as a preventive.

 

POTATO LATE BLIGHT HOT LINE

   The potato late blight hot line began operation on Wednesday, June 2, 1999. It will be available
by calling an 800 number (to be announced later) in the Dakotas and Minnesota. It is available
anywhere by calling 651-696-2263, which is a long distance call outside the Twin Cities. Potato disease
management tips with an emphasis on late blight and early blight will be updated three times a week on
Monday, Wednesday, and Friday. All recommendations will be made by Dr.Gary Secor and Dr. Neil
Gudmestad, Department of Plant Pathology, NDSU. Recommendations are also available on their web site:

http://www.ndsu.nodak.edu/instruct/gudmesta/lateblight/

 

PETAL TEST KITS FOR SCLEROTINIA ON CANOLA

    Reed Agricultural Services in Saskatoon, SK provides petal test kits for determining the infection
potential of Sclerotinia in canola. Most infections occur on the petals. The kits provide a means of
culturing petals in petri plates on a medium suitable for Sclerotinia. An instruction booklet can be
purchased that gives details on performing the test and includes color photos on reading the results.
The kit also contains sclerotia which are plated along with the petals for a positive check of Sclerotinia.
The cultured petals can then be compared to the positive check.

    Adequate sampling of a field requires collecting flowering branches from several areas of the field.
Several hours are required to remove petals, dip them in alcohol and place them on the 25 petri plates
used for each test. A suitable clean work area, such as a large kitchen table, is required. A storage area
for the petri plates is also required – this area should have moderate temperatures and not be exposed
to the sun. Results can be read in 3-3 days. Area specialists in North Dakota and Minnesota who have
used these kits have determined that they provide reasonably accurate information.

    Since 20-30% bloom is the best time to apply Quadris, the 3-3 day waiting period leaves little time
for a spray decision. Results from an early field might give some indication of the potential infection in
slightly later fields in the area, allowing time for a decision and action, if needed.

    A test kit brochure and order form is available from my office (tel. 701-231-7056), the Northern
Canola Growers Association office, and from the NDSU research-extension centers. In Minnesota, the
brochures are available from the Minnesota Canola Council office, the office of Dr. Dick Meronuck,
University of Minnesota extension plant pathologist; and from Jochum Wiersma, University of
Minnesota Northwest Experiment Station, Crookston, MN.

    Further information and ordering is available at 1-800-928-8409. Since orders must clear customs
at the border, shipment would be facilitated if orders from an area are consolidated and directed to a single
address. There is a price break for kits ordered before June 11 and for larger orders.

Art Lamey
Extension Plant Pathologist
alamey@ndsuext.nodak.edu

 

PLANT DIAGNOSTIC LAB REPORT

    First, I need to amend the information on the Round up testing offered through the diagnostic lab. We
can test for Round up injury to trees through the lab, but we can also test any plant material for
Round up injury
. After seeing so many trees in the lab last week, I gave instructions for submitting
trees and neglected to mention that the testing is applicable to all crop plants, nursery plantings, and
yard and garden plants. Whatever plant you might suspect Round up injury to, we should be able to
test for glyphosate, the active ingredient in Round up. As with the trees, it is helpful to have a sample
from the area of the plant or field that is suspected to be injured, and a sample from the area that is
considered unaffected.

    Now that people are beginning to plant flowers and get into their yards, we are starting to see more
turf samples. This spring provided ideal weather, in the Fargo area, for Snow Mold. It was observed all
around the city, on many kinds of lawns. Now that the snow has melted completely and the temperatures
have started to come up, the disease has abated; but diseases that are favored by warmer temperatures
are starting to appear.

    In addition to Snow Mold, there are several other diseases common to lawns in North Dakota. Brown
Patch, the Patch Disease Complex, Pythium blight, and Helminthosporium Leaf Spot and Melting Out are
some of the diseases typically found on lawns. Managing and reducing the impact of these diseases is readily
achieved through good cultural practices in lawn care. These good cultural practices start with cutting the
grass regularly. A good rule is to never cut off more than 1/3 of the blade of grass. It is also best to regularly
sharpen the mower blades so that the grass is cut cleanly and not torn. Try to water in the mornings to allow
the grass leaves to dry in the afternoon. (Leaf wetness and warmer afternoon temperatures contribute
to disease development.) In the hotter parts of the summer, it is a good practice to raise the mower up so
grass is not cut as short. (By leaving the grass longer, the crown of the plants are protected from the higher
temperatures and the grass is less stressed and better able to withstand disease pressure.) Power raking
and aerating in the spring and fall will help reduce excess thatch, if it is there, and provide oxygen to the
root system of the grass. A balance of nutrients in fertilizer will provide optimal growth. High nitrogen will
boost the amount of growth but can also contribute to disease development. High nitrogen is not
recommended after July.

    All of these diseases are caused by different fungi and there are fungicides available to the homeowner
to apply in treatment of any these diseases. Good cultural practices are usually sufficient, but if the problem
simply isn’t getting better, a sample may be submitted to the lab and chemical controls can be recommended
to address a specific disease.

Cheryl Ruby
Plant Diagnostician
diaglab@ndsuext.nodak.edu


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