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Weeds - Diseases - Insects

Thursday, April 1, 1999
filed under: Insects

Sunflower growers in the United States aren't the only ones dealing with troublesome and costly pest problems. A just-released study conducted for the National Sunflower Association suggests that direct losses to world sunflower producers (including the U.S.) from weed competition, plant diseases and insect infestations during the mid-'90s ran in the

area of $ 1.36 billion annually.

That figure includes an estimated $642 million loss to diseases, $490 million loss due to weeds and more than $229 million from insects. The study, conducted by Jay Hesley of Rochester Consulting Group*, encompassed five sunflower production regions: the FSU-12 (12 republics of the former Soviet Union), Argentina, the European Union, Eastern

Europe and the United States. Together, these five regions account for 80 percent of world sunflower output. (Though considered a major sunflower producer, China is not part of this report since no data were available on that nation's degree of pest problems.)

The loss figures include only the estimated value of direct producer losses, Hesley emphasizes. They do not incorporate additional losses due to quality factors, processing inefficiencies or secondary general economy losses.

The study was commissioned to assist companies considering the development of new products to help overcome U.S. sunflower production problems. "Because of the U.S. sunflower industry's small size, high research and development costs, and growing expenses for registering new products, it is difficult for companies to justify new product expenditures," Hesley notes.

"This analysis is organized to identify the major sunflower production problems faced by growers in the United States and in the major sunflower production regions around the world. Identifying these problems and their economic cost to producers can assist companies in

setting research priorities and in estimating a new product's market potential beyond the United States."

Hesley utilized information from a variety of sources, including private and public sunflower industry researchers.

Plant diseases, weeds and insect problems can negatively impact sunflower yields in many different ways, Hesley points out, such as poor germination, seed death, plant lodging, plant deformation, shattering and restricted nutrient uptake, to name just a few.

The impacting factors listed in the accompanying tables will vary from year to year and location to location within a given production region. "Despite the cyclical nature of production problems," Hesley observes, however, "it is important to note that none of the production factors listed in this report currently have techno logies available to cost

effectively and completely eliminate the problem or its impact."

The largest economic losses due to plant disease are found in the countries of the former Soviet Union. Sclerotinia and Phomopsis were identified as the main disease problems for the FSU, with one or both of these diseases also considered major problems in the four other

regions. Sclerotinia likewise is a large problem in three additional (and rapidly expanding) sunflower production areas: Pakistan, India and South Africa, Hesley adds. Together, those three nations account for another eight percent of world production.

The FSU also had the dubious distinction of the highest level - 12 percent - of yield loss to weed pressure. Argentina and Eastern Europe were not far behind at 11 and 10 percent, respectively. One important reason for the FSU's weed problems, Hesley suggests, is the serious financial problems those countries have had over the past decade. "It is believed that weeds were better controlled when producers had the resources to utilize effective control measures and were following Soviet government-mandated rotational requirements," he observes.

Which weeds are most troublesome on a global basis? That's difficult to determine, Hesley points out, since weed problems are more specialized to each growing region than are diseases. "Broomrape, unspecified grasses and Canada thistle were the only weed problems listed in more than one of the regions," he reports.

On a global basis, insects have the least economic impact on sunflower producers of the three pest segments. As with weeds, each region has, for the most part, its own unique insect problems. On a regional basis, U.S. producers lost the highest percentage of their 1994-97 annual production (seven percent) to insects, followed by the EU and Eastern Europe.

Along with the loss of revenue from lower yields, sunflower producers also are subject to lost income due to a seed quality decline as the result of weeds, diseases or insects. For U.S. oil-type sunflower, the major quality factor is seed oil content, with a 2:1 premium generally paid for each percent of oil above 40. Given 1998 numbers (an average harvest price of $9.65 per hundredweight and average yield of 1,548 pounds per acre), a one-percent

decline in oil content would reduce grower revenues by $2.99 per acre.

The cost of substandard quality due to insect damage or disease-impacted seeds is even greater for confection sunflower producers. "If damage causes the reclassification of a grower's seed from human use to bird-food, it can reduce gross revenues by 26 percent under current market conditions," Hesley indicates.

Production problems will impact processing costs as well. "Poor or inconsistent raw seed quality will affect the quality of outputs and possibly result in lower final product prices," Hesley states. "Poor quality can also reduce processing plant operational efficiencies,

increasing costs per unit and lowering processing margins. Both of these losses may be transferred back to the sunflower grower [in the form of] a lower price."

Though yield losses to disease, weeds or insects are unquestionably negative to producer revenue, Hesley adds that there is an element of these losses which can actually partly offset their cost. "In agricultural commodity markets like oil-type sunflower seed, product

prices can rise or fall depending on the level of product supply and buyer demand," he points out. "The production lost to plant diseases, insects or weed pressure may have helped keep sunflower seed prices higher than would have been possible if that lost production were

available in the market."

What are the economics of control measures? "Despite all of the technological advances in agriculture, the most commonly used control measure in all production regions for all production problems is crop rotation," Hesley reports. "Rotating sunflower with other crops - especially grass species - provides control of diseases, insects and weeds" by allowing time between sunflower plantings for the interruption of pest life cycles.

"These interruptions lessen the potential for reoccurrences when sunflower is again planted on the same land," he continues. "Rotating crops also allows for the use of other chemical [treatments] that are not available or compatible for use on sunflower."

In the United States, a four-year rotation is commonly recommended as effective and practical for the management of yield-impacting pests. Other countries, like Argentina, use a much longer rotation time period, Hesley points out, which in turn contributes to improved control of diseases and insects.

The use of cost-effective chemical, genetic or other production controls to manage sunflower pests can have two key benefits, Hesley notes. "First, effective controls can reduce yield losses, which results in higher producer gross revenues.

"Second, effective chemical, genetic and production controls that do not require tillage can save soil moisture. It is estimated that one tillage pass reduces soil moisture by 0.5 inch. Though sunflower has the reputation as a drought-tolerant plant, it usually responds

positively to additional soil moisture. Each inch of moisture can provide [up to] 200 pounds of additional yield potential per acre.

"For example, in 1998, removing one tillage pass through chemical, genetic or production process control of weeds, disease or insects could have resulted in an additional $9.65 per acre in producer gross revenues. (Excess soil moisture can have the reverse impact.)"

Two other damage issues - blackbird depredation and insect damage in stored sunflower - were mentioned in this study but not included in the production loss calculations. Blackbird damage is considered by numerous U.S. sunflower growers in the Northern Plains as one of the most significant "robbers of revenue." Insect damage in stored seed is a worldwide concern. While it does not affect field yields, it does have negative economic impact on seed quality, processing efficiency and product availability.

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