NDSU Crop and Pest Report
Plant Pathology


ISSUE 4  May 22, 2003

BUMPER FUNGICIDE RECEIVES SPECIAL LOCAL NEEDS LABEL

Bumper 41.8 EC fungicide recently received a state special local need (SLN) label from the ND Dept. of Agriculture, for application to wheat up through Feekes growth stage 10.5 or full head emergence. Bumper is a propiconazole fungicide sold by Makhteshim Agan of North America. This label is for control of fungal leaf and glume blotch (Septoria tritici and Stagonospora nodorum) diseases of wheat.

This SLN or 24(c) label is similar to other special local need labels that have extended the window of application to wheat for fungicides whose federal label allows them application only up through Feekes growth stage 8 (early flag leaf emergence). Like Tilt and other propiconazole fungicides, no more than 4 fl oz of Bumper may be applied per season.

Information about 24C state local needs labels and Sec. 18 labels can be found at the NDSU Ext. Service Pesticide Program web site at

http://www.ag.ndsu.nodak.edu/aginfo/pesticid/

If you click on the pesticide label search on the left-hand menu, Andrew Thostenson has done an excellent job of keeping these special labels for ND up to date. Similar and additional information about ND pesticide registrations can be found at the following web site which links to the ND Dept. of Agriculture:

http://www.kellysolutions.com/ND/pesticideindex.htm

 

SMALL GRAIN SEED ROT, LACK OF SEED TREATMENT

Some reports have been made of wheat and barley seed rotting in cold, wet soils. In cases where this phenomenon was observed, seed treatment was not used. Seed treatment products could have provided some protection against seed rots and seedling decay that can result when small grain seed sits in cold soils for three weeks without germinating or emerging.

I do not have statistics on seed treatment use for 2002. However, the ND Pesticide Use Surveys for 2000 and 1996 (NDSU Extension Circular ER-79 and 43, respectively) indicate the % of wheat and barley acreage planted to on-farm seed treated grain.

% of Wheat and Barley Acres in ND Seed-Treated On-Farm, 1996 and 2000

 

Wheat

Barley

1996

41.8%

45.2%

2000

31.9%

37.8%

This downward trend of % acres planted to treated seed may indicate producer’s attempts to control input costs. However, risks of seed rot, seedling blight, root rot, and loose smut are high when seed treatments are not used. Some growers this year may wish they had spent the extra dollar or two rather than have to replant or have poor stands.

 

WHEAT TAN SPOT OBSERVED

Early season symptoms of tan spot infections have been observed on winter wheat in Ransom Co. and was abundant in some spring wheat fields in the western part of ND. Symptoms also were observed in Benson Co. by Terry Gregoire, Area Agent, and Scott Knoke, county agent.

Information about control of early season tan spot with fungicides was provided in the Crop and Pest Report #2, May 8, 2003. Information about tank mixes of fungicides and herbicides was not included in that report. That information follows.

 

TANK MIXES OF HERBICIDES AND FUNGICIDES FOR WHEAT TAN SPOT CONTROL

The 2003 North Dakota Weed Control Guide, NDSU Ext. Circular W-253 provides, a nice summary table on restrictions or tank mixing of herbicides with Tilt or mancozeb fungicides, on page 76. Most herbicide tank mixes are NOT prohibited with these two fungicides. However, tank mixing of Achieve and Cheyenne herbicides with either fungicide is prohibited by the herbicide label and Stampede is prohibited from being tank mixed with Tilt. The table recommends seeing the label of Bromoxynil for tank mix information for this herbicide and these two fungicides.

This table does not contain information about tank mixing with some of the newer fungicides. The generic propiconazoles Bumper, Propimax and Contend would be expected to have responses in tank mixes similar to that of Tilt.

The Stratego label has no statement prohibiting specific herbicide tank mixes, but does recommend a jar test for testing physical compatibility of the products and gives specific directions on order of products in the spray tank. The Stratego label does prohibit using an organosilicate surfactant.

The Headline label states that it can be tank mixed with most recommended herbicides. The Headline label also recommends testing combinations of products on small portions of the crop to ensure that a phytotoxic response doesn’t occur.

When fungicides are tank mixed with herbicides, an additional adjuvant for the fungicide generally is not recommended. The herbicides often have their own adjuvant and additional ones could cause crop burning.

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

 

NEW CERCOSPORA LEAF SPOT OF SUGARBEET PUBLICATION

A new Cercospora leaf spot of sugarbeet publication has been written by NDSU and Univ. of MN specialists Carol Windels, Carl Bradley, and Mohamed Khan. The 1-page extension circular (PP-1244) is titled, "Comparison of Cercospora and Bacterial Leaf Spots on Sugarbeet" and includes several color photographs and tips to help distinguish Cercospora from bacterial leaf spot. The circular is available from the NDSU Extension Distribution Center (dctr@ndsuext.nodak.edu or 701-231-7892).

 

SEED TREATMENT ON LATE-PLANTED SOYBEAN

With all of the moisture keeping the planters from rolling, soybean planting will be pushed back to late May to early June this year. The soil temperature in early June should be warm enough to allow quick germination and emergence. With the quick emergence, is a fungicide seed treatment necessary? The answer depends on how uniform you like your stand and the benefits gained from a uniform soybean stand. Even in ideal soil temperatures, soybean stands can still be reduced by 10% due to seedling blights. With the high cost of seed of some varieties, it is important to make every seed count. A fungicide seed treatment will protect against stand loss for approximately $1.50 to 2.50 per unit of seed. A uniform soybean stand allows for better weed control and better seed quality.

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


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