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2011 Crop Survey Report

Monday, January 2, 2012
filed under: Research and Development

By Hans Kandel

The National Sunflower Association has conducted in-depth field surveys throughout the main sunflower growing regions of the United States (and Manitoba, Canada) for the last 10 years, with the exception of 2004.

During September 2011, qualified teams including agronomists, entomologists, pathologists, crop consultants and/or producers randomly stopped at approximately one field for every 10,000-15,000 acres on a county basis. Each team spent at least 45 minutes per field and filled in a standard evaluation form. The specialists determined the most limiting and second most limiting yield factors. They also assessed the incidence and type of diseases and weeds, presence and damage by insects, bird damage and agronomic practices used in the field.

A yield estimate was calculated based on plant stand, head size, seed size and seeds per head. The 2011 average surveyed sunflower yield was 1,642 lbs/ac with an average per-acre plant population of 15,766.

Determination of yield-limiting factors was based on the surveyors’ judgment. Different regions of the U.S. and Canada may have differences in the main limiting factor. For instance, in the wetter areas of North Dakota, Manitoba and Minnesota, disease may have been the most limiting factor, whereas Dectes long-horned beetle damage was mostly concentrated in the southern production region.

Overall, the most limiting factor in 2011 was plant spacing within the row, followed by disease. Regardless of the 2011 planting conditions, it should be noted that plant stands and plant spacing within a row have consistently ranked as top limiting factors since the first survey was conducted in 2002.

The plant spacing difficulties consist of either a skip within the row, or areas where plants grow too close together, causing one of the plants not to contribute to the sunflower yield. Equal distribution of plants is essential to obtaining the maximum yield.

Skips in rows have many potential causations, including no seed drop during planting, dormant seed, poor seed-to-soil contact, seedling disease, lack of moisture, insect damage, or even feeding damage by animals. Producers should pay attention to their management and refine their technique while seeding sunflower. Planter calibration may be the first step to reducing skips. There appear to be more skips in solid-seeded fields when airseeders are used.

In 14% of the fields no limiting factor could be determined, and in 30% of the fields “no problem” was reported for the second limiting factor. The “no problem” category indicates that the evaluators felt the field reached its maximum yield potential for that particular growing season.

The diseases of most concern in sunflower are rust, Sclerotinia and Phomopsis. Rust incidence in 2011 was down in Colorado, Kansas, Minnesota, North and South Dakota and Texas compared with 2010, but rust was detected in all surveyed fields in Manitoba. Sclerotinia head rot in fields with the disease was down in Manitoba. Head rot severity was similar compared with last year in North Dakota, while head rot was absent in Minnesota and South Dakota. (See graph on next page). Phomopsis was a major concern in Minnesota, where 45% of the plants in infected fields were diagnosed with the disease. The percent diseased plants with Phomopsis in North and South Dakota was up when compared to 2010. Nebraska fields had similar levels of Phomopsis-infected plants in both years.

The highest percent severity of long-horned beetle (plants with the insect) was found in Kansas, followed by Texas and South Dakota.

Bird damage was reported in 67% of the surveyed sunflower fields in Manitoba, 46% in North Dakota and 39% in South Dakota.

Broadleaf weeds continue to be more of a problem than most grassy weed species. Palmer amaranth is a major problem weed in Kansas and was recorded as being present in 100% of the surveyed fields. In Texas, 71% of the fields contained Palmer amaranth.

Sunflower growers are encouraged to use information generated in this survey to manage their sunflower fields. Producers can adjust their planting equipment, work on optimum weed control, apply fungicides when needed and reduce bird feeding on the sunflower crop.

This survey data also will be used to help define research priorities in improving sunflower crop production and the bottom line for producers.

Hans Kandel, extension agronomist with North Dakota State University, is coordinator of the annual sunflower crop survey.
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