NDSU Crop and Pest Report
Plant Pathology


ISSUE 4  May 23, 2002

 

FUNGICIDES FOR RHIZOSPHAERA NEEDLECAST ON SPRUCE

The following table lists several fungicide formulations available for treating Rhizosphaera needlecast on spruce. Ortho MultiPurpose Fungicide is also available but rates were not available by publication deadline. Approximate costs for these treatments was also not available by publication deadline, but all this information should be available in the lab by Friday, May 24. Call (701.231.7854) or email to get it, or look for another update in next week’s pest report.

Fungicides for Rhizosphaera needlecast

chlorothalonil
Bravo 500

 

8 pts/100 gal water
( not > 8 pts/acre)

Begin application when new growth is at ˝ -2 in., repeat every 3-4 wks while disease conditions are favorable*. Use the shorter interval during periods of rain and heavy disease pressure.

 

1Min re-treatment interval:
21 days for est. trees
7 days for nursery trees

Bravo Ultrex1

5.0 lb/100 gal water
(not to exceed 5 lb/acre or 20 lb/season)

Bravo Weatherstik

5 ˝ pts/100 gal water

Concorde DF

5 lbs/100 gal water
(not > 5 lb/acre)

Daconil Ultrex1

5 lbs/100 gal water

Daconil Zn Flowable

8 pts/100 gal water
(not > 8 pts/acre)

Daconil Weatherstik

5 ˝ pts/100 gal water
(not > 5 ˝ pts/acre)

Manicure Ultrex1

5 lbx/100 gal water
(not > 5 lbs/acre)

Pathguard 6F

5 ˝ pts/100 gal
(not > 5 ˝ pts/acre)

Pathguard 90DF

4 ˝ lb/100 gal water
(not > 4 ˝ lb/acre)

chlorothalonil + fenarimol
Twosome

˝ - 1 1/4 fl. oz/gal water or 8 pts/100 gal water

Apply at bud break, and again 3-4 weeks later

Cheryl Biller
NDSU Plant Diagnostician
diaglab@ndsuext.nodak.edu

 

UPDATE ON CEREAL DISEASES IN SOUTHERN PLAINS, MAY 21

The latest Cereal Rust Bulletin, published by the USDA/ARS Cereal Disease Laboratory, St. Paul, indicates that wheat leaf rust is common in southern Kansas and northern Oklahoma. Severity levels in Kansas remain at trace levels, but in Oklahoma, severities are at 10% or above. The Rust Bulletin states that these rust infections "will provide inoculum for the northern wheat growing area and especially where the crop is behind normal crop maturity".

Since most of our crop will be behind normal crop maturity, our wheat will be at increased risk to rust infections this year. Development will be dependent on weather conditions during the growing season, but crop monitoring for wheat leaf rust is a must this year.

Kansas plant pathologists indicate that barley yellow dwarf virus (BYDV) will probably be the biggest disease problem in Kansas wheat this year. The grain aphids that carry this virus may blow up to North Dakota from southern states, on prevailing winds. BYDV could also be a threat to our late seeded wheat and barley crops this year.

The May 21st Cereal Rust Bulletin also indicates that wheat stripe rust has been detected in Kansas. This rust likes cool, wet conditions. Oat stem rust has been found in Texas, and the aecial (alternate host) stage of oat crown rust has been observed on buckthorn leaves in St. Paul. Barley rusts have not yet been reported in southern Plains states.

 

NDSU IPM FIELD SCOUTS AND SURVEY

Training for NDSU’s IPM field scouts was held in Carrington on May 20. The IPM scouts last year surveyed almost 1500 small grain fields for leaf and head diseases and insect pests. This year the scouts will be concentrating on key pests of five major crops at specific growth stages. The crops and pests that will be surveyed for this year include:

* Wheat: leaf and head diseases, cereal leaf beetle, grain aphids, wheat midge

* Barley: leaf and head diseases, cereal leaf beetle, grain aphids, barley thrips

* Canola: flea beetles, black leg, white mold, and Alternaria black spot

* Sunflower: downy mildew, sunflower beetle, and red seed weevil

* Soybean: soybean aphids

The IPM scouts, their location of operation, and their scouting coordinators are:

* Patrick Metzger, sophomore at Valley City State, operating out of the Carrington Research Extension Center under the direction of Greg Endres, NDSU Extension Area Cropping System Specialist

* Sheri Trumbull, previous experience in potato pest management at the Univ. of Maryland, and Christen Laventure, sophomore at Dickinson State University, operating out of the Dickinson Research Extension Center under the direction of Roger Ashley, NDSU Extension Area Cropping Systems Specialist

* Matthew Gregoire, senior at NDSU, operating out of the Fargo Experiment Station under the direction of Marcia McMullen, NDSU Extension Plant Pathologist, and Phil Glogoza, NDSU Extension Entomologist

* Holly Semler, recent graduate of Minot State University, Kelly Novak, senior at NDSU, and Chris Rylander, junior at Minot State University, operating out of the North Central Research Extension Center under the direction of Jan Knodel, NDSU Extension Area Crop Protection Specialist. Lorilie Atkinson, recent graduate of Minot State University, and Brooke Klein, student at Surrey High School, will be assisting the scouts at Minot.

Some of the above survey efforts are in conjunction with survey projects coordinated by Stephen Neate, NDSU Barley Plant Pathologist, Art Lamey, NDSU Professor Emeritus and consultant to the ND Canola Council, and Tom Gulya, USDA/ARS Sunflower Plant Pathologist.

Marcia McMullen
NDSU Extension Plant Pathologist
mmcmulle@ndsuext.nodak.edu

 

SECTION 24C LABEL FOR BRAVO ULTREX ON CHICKPEA

Bravo Ultrex (chlorothalonil, Syngenta) has been granted a special local needs (24c) label for pre-bloom application on chickpea for management of Ascochyta blight. The use rate is 1.25 to 1.8 lbs / acre, and can be applied up to 5 times in a season as long as no more than a total of 7.2 lbs / acre is applied. Applications should begin at first onset of the disease, which may occur 2 to 4 weeks before flowering. Growers now have two chlorothalonil products that can be applied to chickpea at the pre-bloom stage, as Equus DF (Griffin L.L.C.) also was granted a section 24c label a few weeks prior (see NDSU Crop and Pest Report issue no. 2).

Carl Bradley
Extension Plant Pathologist
cbradley@ndsuext.nodak.edu


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