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’09 Crop Survey Summary

Tuesday, December 1, 2009
filed under: Research and Development

The National Sunflower Association has been conducting intensive field surveys for nearly 10 years in an effort to keep on top of emerging production problems.

The project is based on one survey field per 10,000 acres in a given county. Volunteers conduct the survey, with each using the same survey and reporting format. A GPS reading is taken at each location so maps can be developed to determine if a certain kind of pest is region-specific or expanding in a region in comparison to previous years’ surveys. The survey results are a guide for NSA research priorities and funding.

Surveys are conducted at slightly different times throughout the production region. Efforts are made to have the surveys conducted just prior to crop maturity or a killing frost. Doing so allows for better recognition of disease, insect, weeds and other production issues.

Dr. Duane Berglund, retired North Dakota State University professor emeritus, again coordinated the survey this year and is in the process of finalizing the data.

Disease #1 Issue in North

Given the cool and wet weather throughout the 2009 growing season, it was not surprising to find diseases as the foremost yield-limiting factor in the northern growing region (including Manitoba). Red rust was the most common disease found throughout the entire production region. In most cases, however, its incidence was not yield impacting. It was not possible to determine, during the survey, whether fungicides had been used on the specific fields earlier in the season.

Phomopsis (a stalk disease) was common in the Dakotas, Minnesota and Manitoba, but may have manifested later in the season. Stalk breakage from the disease was minimal at the time the survey was taken, but may have increased during the harsh “nonharvest” month of October. The disease was not found to any degree in Kansas and Colorado, which is in contrast to the 2008 findings.

Sclerotinia head rot was most common in northeastern North Dakota, southeastern Manitoba and northwestern Minnesota. The disease likely accelerated in October, and considerable damage is expected in that area. Mid-stalk Sclerotinia — which causes plants to break and lodge — was more common in 2009 in the northern region than past years. The telltale hard-bodied sclerotia are easily found in the broken stalk.

Verticillium is an emerging disease found commonly in 2007 and 2008; but it was almost nonexistent in 2009. Stalk samples from each field were collected for further laboratory analysis. Common in potaotes, this disease apparently was absent in that crop as well in 2009. Charcoal rot was found in a few isolated areas of Minnesota — rather unusual since this disease is most often found in hot and dry environments. That was not the case for west central Minnesota in 2009. USDA-ARS plant pathologist Tom Gulya has taken disease samples and plans further research. A concern for the future is that sunflower, corn and soybeans are all hosts to the pathogen.

Insects & Blackbirds

Seed samples from each field are collected and analyzed at the USDA-ARS Sunflower Research Unit laboratory in Fargo to determine the level of seed insects such as seed weevil and banded moth. Surveyors also look for webbing on the face of the heads, which is an indication of either the banded sunflower moth or the sunflower moth.

The 2009 incidence of webbing was markedly higher in Minnesota and the Dakotas compared to 2008. This is an indication of banded moth, and laboratory tests will determine the level of seed damage. Webbing was considerably lower in Kansas and Colorado compared to other years, which points to lower levels of the sunflower (head) moth and/or successful control of the insect.

The NSA survey found damage from blackbirds to be less in North Dakota and Minnesota compared to previous years, but greater in South Dakota, Kansas and Colorado. USDA’s Wildlife Services has administered a more-aggressive blackbird dispersement program for the last two years in the Dakotas. Another reason for the decline in North Dakota may be that farmers with considerable damage in the past have simply stopped raising the crop.

Weeds: Kansas & Colorado Wrestle Most

For the last several years, weeds have been identified as a minor problem in the northern states. This is due to more and better sunflower herbicide choices and better weed control within the rotation with other crops. Finding a highly weed-infested sunflower field in the region is the rare exception today.

Canada thistle and kochia are the most common weeds found in North Dakota and Minnesota, while redroot pigweed and kochia are the most common weeds seen in South Dakota sunflower fields. Overall, though, infestation levels of these weeds are low.

Kansas and Colorado are another story, however. In Kansas, the weed known as palmer amaranth is a significant problem. This weed is in the pigweed family and is very competitive, growing above the sunflower canopy. Palmer amaranth has developed ALS and glyphosate resistance, thus complicating control options. Researchers find it to be a problem in first-crop sunflower, but not in double-crop ’flowers after winter wheat.

Russian thistle and puncture vine were the most common weed species found in Colorado sunflower fields this year.

Biggest Issue: Plant Spacing

For the past several years, surveyors have found plant spacing to be the major production problem in all states. Inadequate plant spacing is defined as plant skips within the row or within a solid-seeded field. Typically, the neighboring plants will compensate for one or two missing plants. But there often have been several plants missing in sequence, with the ensuing large gap then taken up by kochia or other weeds. Yield has been compromised in such instances.

Although plant spacing continues to be identified as a yield-depressing factor, the problem seems to be declining each year. That is likely due to better drill calibration, seed treatments eliminating seedling disease and insect damage, and good soil moisture at planting.

Survey Affirms Research Priorities

The 2009 NSA crop survey results confirm that existing research priorities and programs are on the right track. The vast majority of public research and NSA research funds are expended on identifying disease and insect resistance. Getting additional herbicides is problematic, as there are few products in the experimental pipeline that show potential for broadleaf weed control in sunflower.

The final 2009 survey results will be reported at the NSA Research Forum in Fargo on January 13 and will be placed on the NSA website shortly thereafter. — Larry Kleingartner

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