ISSUE 1 May 13, 2010
NDSU POTATO BLIGHTLINE TO OPERATE IN 2010
The Plant Pathology Department at NDSU will again be providing the potato blightline service at no charge to the potato industry of North Dakota and western Minnesota in 2010. It is not too early to talk about the localized late blight epidemic of 2009, reminding the growers how important it can be, how fast it can spread, and that this hotline is the first line of defense to get the most recent management information disseminated.
This will be the sixteenth year that this service has been provided and sponsored by Syngenta Crop Protection. The hotline uses local weather data collected from weather stations throughout our area to forecast the occurrence and spread of late blight in fifteen non-irrigated and twelve irrigated production areas in ND and western MN. The data is processed by the North Dakota Agricultural Weather Network (NDAWN) and analyzed by a computer program (WISDOM) to forecast when conditions are favorable for late blight to occur.
The forecast information is used by plant pathologists Gary Secor and Neil Gudmestad to make late blight management and fungicide recommendations. The recommendations are made Monday, Wednesday and Friday of each week during the growing season. The first late blight hotline will be Monday June 1st, and it is anticipated that the hotline will continue through mid-September depending on disease pressure. The hotline will also be used to confirm reported late blight sightings and serve as clearing house for national late blight information. In addition to late blight forecasting, the hotline also provides cumulative P-values for early blight disease forecasting and management recommendations. Finally, it serves to alert growers of other disease and insect news, as well as posting messages of general interest such as potato field day dates.
The hotline recommendations can be accessed by phone or website. The toll free phone number is 888.482.7286. The NDAWN website for potato disease forecasting contains colored maps of ND to pictorially illustrate the late blight severity values (both two day and seasonal), favorable day values and P-day values for early blight throughout ND. That site is: www.ndawn.ndsu.nodak.edu. Go to applications and then click the potatoes drop down box.
You can also connect to the latest blight hotline news and message update reminders by text messaging type BLIGHTND to 97063 or on Twitter follow @SyngentaSpuds.
Growers and scouts are encouraged to send suspect late blight samples to us for positive identification. Late blight is a community disease and proper identification and prompt notification is important. Leaf samples should be placed in a slightly inflated zip-lock plastic bag without a wet towel and sent to:
NOTE new mailing address: Gary Secor, NDSU Dept 7660, Box 6050, Fargo, ND 58108. Our phone number is 701.231.8362 and email address is email@example.com.
We wish you a successful potato year.
CHANGES TO SOYBEAN RUST MONITORING IN 2010
Soybean rust is a potentially devastating disease, but it can only survive the winter months where it is protected from freezing. As such, the pathogen can overwinter only along the gulf coast states, and it must blow north to cause problems in North Dakota. This makes monitoring pathogen movement critical. For the past few years, soybean rust has been monitored intensely throughout the United States by scouting of sentinel plots – designated areas of soybean fields that are visited weekly. The information was then made available to the public on the soybean rust website, www.sbrusa.net.
Soybean rust monitoring will still be done in 2010, but changes are being made to the system.
The bulk of the soybean rust monitoring will be concentrated in the South, where the pathogen begins its yearly cycle. Data will be collected from sentinel plots in the states bordering the gulf, and will be supplemented by data generated from ‘mobile scouting’, which is essentially random field sampling. The Midwest and Northern United States will largely be operating in a volunteer context. Some sentinel plots will be in operation, but the numbers will be greatly reduced from years past. North Dakota, which has had 20 sentinel plots for the past three years, will field two. However, if soybean rust progresses north, we expect to stay on top of pathogen movement by beginning a mobile scouting effort. All this information will be made available on the soybean rust website in the same way it has been in the past.
North Dakota has made additional preparations for soybean rust. The North Dakota Soybean Council, the North Central Soybean Research Program, The University of Florida, and the NDSU Extension Service worked together to send 35 North Dakotans (primarily county agents and crop consultants) to a soybean rust training course in the U of FL Quincy Research Florida panhandle last August. The Quincy station is home to the majority of soybean rust research in North America, and annually holds two-day diagnostic and management workshops for the disease. Those attending the workshop will be fully aware of the difficulty in accurate identification, the necessity of non-visual identification techniques (laboratory based techniques), and understand the best management strategies currently available. This group of people will serve as a critical mass to identify and manage soybean rust if it gets close to our crop.
The soybean rust website (http://www.sbrusa.net) is a useful tool for anyone interested in soybean rust movement, diagnosis, or management; and will again provide public access to soybean rust progression throughout the United States.
Extension Plant Pathologist
WSMV AND HIGH PLAINS VIRUS
Wheat streak mosaic virus (WSMV) has been confirmed in 13 of 16 winter wheat samples submitted to the NDSU Plant Diagnostic Lab. The majority of these positive samples have been located in fields in north central ND (please see Dan Waldstein’s report and his pictures of WSMV, found in the North Central Research and Extension section of this Crop and Pest Report; also, please see Jan Knodel’s discussion on wheat curl mites in the Entomology section of this Crop and Pest Report).
The NDSU Plant Diagnostic Lab also is testing submitted samples for other viruses, such as High Plains Virus and Barley Yellow Dwarf Virus, as part of a Great Plains Wheat Virus Survey. Eight of the 13 samples positive for WSMV also were positive for High Plains Virus (HPV). Both WSMV and HPV are transmitted by the wheat curl mite, cause similar symptoms in wheat, and are managed the same, primarily through planting dates and destruction of volunteer wheat or infested wheat crops. HPV was first diagnosed in corn, in Nebraska in 1993. It may cause yellow streaking in infected corn leaves as well as in wheat leaves. HPV has not been confirmed in corn in ND.
TAN SPOT OBSERVED IN SOME WINTER WHEAT
Abundant rains across the state will favor tan spot fungal infections in wheat, once temperatures warm up. Tan spot infections have already been observed in some winter wheat crops.
Early season fungicide applications will most likely be used on some of these crops. Hopefully, no one is going to be applying herbicide plus fungicide combinations until night temperatures get above freezing or into the 40s, as cold temperatures coinciding with application of these herbicide plus fungicide mixes have resulted in some crop injury in the past.
NDSU DISEASE FORECASTING SITE FOR WHEAT NOW ACTIVATED FOR SEASON
The NDSU Small Grain Disease Forecasting website is now operational for 2010. This site provides information on risk of the following fungal diseases: tan spot, leaf rust, Septoria blotch, and Fusarium head blight (scab). The risk of disease is based on environmental variables as determined by the North Dakota Ag Weather Network (NDAWN) weather stations. The website address is:
Currently, many of the NDAWN weather stations have indicated that we have had weather favorable for tan spot fungal infection. Generally, the temperatures have been too cold for other fungal diseases. As temperatures warm up, risk of tan spot infection will increase on winter wheat and on emerged spring wheat fields planted into wheat residue. More information on the Fusarium head blight (scab) model will be shared in next week’s Crop and Pest Report.
WHEAT RUST IN THE SOUTHERN PLAINS
Extension Plant Pathologists from Oklahoma and Kansas are reporting stripe rust and leaf rust as common to severe (as of May 7th) in susceptible winter wheat cultivars such as Jagger, Jagalene, and Overly. Winter wheat in Oklahoma is ranging from the completion of flowering to near maturity stages, while in Kansas, growth stages range from flag leaf emergence to flowering.
What do these disease occurrences portend for ND? The potential exists for leaf rust infection on susceptible winter and spring wheat cultivars, because spore production is developing abundantly to our south. As for stripe rust, this disease has not been a problem in ND, because the fungus generally encounters too warm of temperatures by the time spores reach the region. However, we will keep our eye on conditions and disease development as the season and crop progresses.
Information on cereal rust development is updated at least weekly and is available at the USDA/ARS Cereal Disease Lab website:
NDSU Extension Plant Pathologist
SOIL TEMPERATURE AND SUGAR BEET SEED EMERGENCE
Sugar beet seeds germinate and emerge over a wide temperature range in the presence of adequate soil water and oxygen supply. In most years, soil temperature at the 4 inch depth at planting time in mid-April is about 45 F. A soil temperature of at least 38 F is required to initiate germination in sugarbeet. Seeds should be planted into seedbeds when conditions are favorable for the seeds and seedlings during germination, emergence and early crop establishment. Planting should be done at a time that will facilitate early emergence and uniform and rapid growth of seedlings.
This April was the warmest on record since 1915. Conditions were favorable for planting sugarbeet resulting in more than 90% of the crop being planted by the end of April. In 2006, sugarbeet planting was completed by mid-May, and growers at American Crystal Sugar Company had their largest sugarbeet crop. With favorable growing conditions and no major disease issues, growers should have another good sugarbeet crop – maybe another record crop.
The following table gives approximate days to emergence of sugarbeet seeds at different soil temperature ranges.
Soil Temperature ( F)
Days to Emergence
21 days or more
PROJECTIONS FOR 2010 SUGARBEET CROP
The total sugarbeet acreage in the US for 2010 is projected at about 1.17 million acres.
Sugarbeet acreage in North Dakota and Minnesota will be slightly higher than last year. American Crystal Sugar Company will plant about 424,000 acres, Minn-Dak will plant 115,000 acres, and Southern Minnesota Beet Sugar Cooperative will plant 116,000 acres. Growers in western North Dakota and eastern Montana will produce 31,000 acres of sugarbeet that will be processed in Sidney, Montana. This means that North Dakota and Minnesota will plant just over 686,000 acres of sugarbeet which is about 59% of the US sugarbeet acreage.
Growers will be continue their efforts at improving efficiency by properly preparing seed beds, using starter fertilizer, and using adequate seeding rate to start with a good plant population to give their crop a solid foundation. Most fields - over 94% - will be planted to Roundup Ready sugarbeet so timeliness of glyphosate applications will be critical. Seeds should be planted into dry or moist seedbeds. The ideal planting date for the Red River Valley, based on American Crystal Sugar Company data base, is around April 25. Most sugarbeet fields were planted by April 30.
I encourage all growers to adopt best management practices to have a profitable sugarbeet crop in 2010, and always, practice safety.
PLANT POPULATIONS FOR HIGH SUGAR BEET YIELD AND QUALITY
Research done at North Dakota State University and the University of Minnesota showed that a wide range of population resulted in high recoverable sucrose, but plant populations of 175 to 200 plants per 100 foot of 22 inch wide rows consistently resulted in the maximum recoverable sucrose per acre. It is important that the plants be evenly spaced within the rows.
Lower plant populations (less than 100 plants /100 ft of row) take longer for the canopy to completely cover the soil resulting in emergence of weeds later in the season. In conventional sugarbeet, effective weed control becomes more difficult and costly with lower populations. However, weed control is not a problem for growers using glyphosate tolerant sugarbeet, even when populations are reduced, say by insects, diseases or wind. One of the important factors for high sugarbeet yields is early planting – ideally around April 25 which typically results in highest yield. Research shows that early planting of populations of 75 to 100 plants per 100 ft of row will produce higher yields than higher plant populations planted three weeks later in similar growing conditions. As such, any replanting of sugarbeet because of poor stands should be carefully considered.
Plant populations higher than 225 plants per 100 foot of row result in too much competition among the plants, and defoliation becomes difficult. Sugar beet fields with populations higher than 225 plants per 100 foot of row planted at 22 inch row spacing should be thinned to about 175 to 200 plants per 100 foot of row.
There are a few growers who use 30 inch row spacing; these growers should aim for a plant population of about 215 to 225 plants per 100 foot of row to get highest yield and quality.
At this time, most growers have completed planting which should result in row closure by June 21 under favorable environmental conditions. Should we have a good growing season, the foundation is laid for record sugarbeet yields.
Extension Sugarbeet Specialist
NDSU and University of Minnesota