Consider Seed Treatments as Planting Insurance

Especially for no-till, wheat-on-wheat, and adverse weather conditions

By Tracy Sayler and Jerry Schleicher

With all the advancements and knowledge applied to production agriculture these days, it seems surprising that there’s still debate about the value of seed treatments. Indeed, some growers skip seed treatments to cut costs, even in the following common situations when a seed treatment is needed most:

• Using saved (bin run) seede, specially seed that may have blackpoint or other seed-borne diseases
• Continuous cropping, including wheat-on-wheat
• No-till/planting into high residue
• Planting into CRP ground brought back into production
• Adverse weather conditions (like last spring, when emergence in many situations was delayed by cool, wet conditions)
• When wireworms are present

The wireworm is a crop pest that growers should watch for early in the growing season, particularly in a no-till system. This should not come as a surprise, since this and other insects often feed or lay their eggs where there is a lot of plant residue. It can be a drawback to no-till, as can greater susceptibility to plant disease. The drawbacks should be taken in context with the benefits of no-till, however, including soil and water conservation, increased yield potential in dry conditions, and savings in time and cost of primary tillage operations. (The Manitoba-North Dakota Zero Till Association web site has an excellent online resource for northern no-till production information, at www.mandakzerotill.org .)

Wireworm larvae are hard, smooth, slender, and wire-like, varying from 1½ to 2 inches in length when mature. They are a coppery color with three pairs of small, thin legs behind the head. Adult wireworms are bullet-shaped, hard-shelled beetles that are brown to black in color and about ½ inch long. Their common name – click beetle – is derived from the clicking sound that the insect makes when attempting to right itself after landing on its back.  Adult click beetles can be found in the grain tank of a combine at harvest in fields where the insect has been a problem.

A seed treatment that includes an insecticide will help control wireworms, a crop pest that growers should watch for early in the growing season, particularly in a no-till system. Photo courtesy Phil Glogoza, NDSU

Wireworms can be confused with cutworms (armyworms) which become moths as adults. The key difference is that the cutworm/armyworm is more plump and softer-bodied than the wireworm. Also, wireworms have a longer life cycle than cutworms, and usually feed on roots and germinating seedlings below ground.

Entomologists say there is no “rescue” treatment for wireworms.  Managing a soil insect like the wireworm which stays below ground is best dealt with during planting. Damage from this insect is most likely to appear in the spring when soil temperatures warm to 50 F, and wireworm larvae begin to migrate upward to within 6 inches of the soil surface to feed on newly planted seed and young seedlings.

Wireworms prefer more moist, cooler soil temperatures (50-55 degrees F) and move deeper into the soil if soil gets too dry and when soil temperatures become too hot (>80 F). The insect can feed on germinating wheat seed, as well as seedling roots and coleoptiles. The visible signs of wireworm feeding include gaps in the row, or wheat or barley seedlings wilting or dying in patches.

Cutworms, which usually feed above ground on young plants at night, can be managed with insecticides after crop emergence. Cutworm damage consists of young plants chewed off slightly below or at ground level. When checking fields for cutworms during the day, dig down into the soil an inch or two around recently damaged plants, where larvae are likely to be found.

Early-season prevention and scouting is critical for managing both insects.  More information on wireworms from North Dakota State University can be found online at www.ext.nodak.edu/extpubs/plantsci/pests/e188-1.htm and on the army worm and army cutworms at www.ext.nodak.edu/extpubs/plantsci/pests/e830w.htm .

Protection against early season diseases
Seed treatments can also help prevent/suppress disease pathogens that can attack wheat seedlings and ultimately reduce yields. These early season diseases include take-all, common root rot and foot and crown rot, smuts, and Pythium.

Marty Draper, South Dakota State University extension plant pathologist, says that root and crown rotting diseases are among the most common and destructive diseases of wheat in South Dakota. “In an average year, we estimate those pathogens cause as much as a 3 to 4% crop loss, and the toll can certainly increase under no-till or reduced-tillage programs, as well as dry conditions that favor common root rot and Fusarium foot and crown rot.”

Greater interest the past few years in “intensive wheat management” is bringing more attention to seed treatments.  “The high-input growers in our area tend to plant early, often into cold soils; and more and more of them are following a no-till program,” says Doug Abeln, a spring wheat grower and owner of Abeln Seed Company at Groton, S.D. “I’d say about 75% of the growers I sell seed to now order their seed treated with products such as Raxil MD to improve their germination, protect their stands from disease and improve their yields.”

Seed treatments will go a long way in ensuring healthy wheat root development.  For suppression of common root rot in small grains, a seed treatment should include one of the active ingredients: Imazalil, difenconazole, or tebuconazole.  Photo: Jerry Schleicher

Seed-applied fungicides can also prevent fungi from colonizing seed when soil temperatures remain too cold to spark germination. Early last spring, for example, temperatures dropped as low as 28 degrees after some spring wheat fields had already germinated, according to Gary Erickson, Brown County Extension agent at Aberdeen, S.D.

“Given the cold weather we had last spring, I’d guess that some seed may have laid in the seedbed for a couple of weeks or longer before the temperatures began to warm up,” says Draper. “If you combine cool soil temperatures with a lot of crop residue, which can serve as insulation to delay soil warm-up, you can definitely increase the risk of pathogens attacking the seed and seedlings.”

Jay Jones, a Bath, S.D., grower who produces about 1,800 acres of spring wheat under what he calls a modified intensive management program, says he prefers to start planting in late March. Steve Schaller, a no-till grower from Conde, S.D., whose high-yield program has produced spring wheat yields ranging from 60 to 80 bushels per acre, says he’s planted wheat when soil temperatures were still in the upper 30s. Both growers report that using a seed treatment helps to improve seedling vigor and prevent seedling diseases.

SDSU’s Draper says he’s seen an increase in the incidence of Fusarium root and crown rot in South Dakota fields over the past five years. He recommends that wheat producers treat their seed with a broad-spectrum fungicide if they plant early, follow reduced-tillage or no-tillage programs, or plant wheat after wheat.

NDSU extension plant pathologist Marcia McMullen says that seed treatments result in a yield boost of about two to four bushels an acre on average – sometimes less, sometimes more, depending on the conditions. The degree of control will vary with product, rate, environmental conditions and disease organisms present.

In a research trial conducted at Jay Elkin Farm near Taylor, ND in 2003, eight registered and experimental fungicide seed treatments were evaluated for the control of fungal root and crown diseases on the hard red spring wheat variety Parshall. Roger Ashley and Glenn Martin of the NDSU Research Extension Center, Dickinson, conducted the study at a site that had grown continuous wheat since 1996.

Among their findings: Raxil MD + Gaucho 480FS seed treatment (commercially marketed as Raxil MD-W, which includes the insecticide imidacloprid) increased grain yield significantly over the untreated check plot, but was not significantly greater than Raxil MD. Their research also indicated that Parshall is sensitive to methyl bromide soil fumigant and/or its metabolites. Full details of this study can be found online at www.ag.ndsu .nodak.edu/dickinso/research/2003/agron03i.htm.Caution should be given to extrapolating this one year of data to other environments, where soil/weather conditions (as well as wireworm pressure) may vary.

Some treatment costs can vary, from about $1 to over $2 per bushel of seed.  Treatments that include an insecticide and broader spectrum early season disease control will be at the higher end of the scale.

For suppression of common root rot in small grains, the seed treatment should include one of the following active ingredients,  Imazalil, difenconazole, or tebuconazole, all systemic seed treatment fungicides registered for use on wheat or barley for suppression of common root rot infection. Imazalil is not considered to be a stand alone treatment and is recommended to be used in combination with other seed treatment products that provide protection against seedling blights, seed rots, and smuts.

While on-farm treatments may help save on cost, some experts point out that on-farm seed treatments can result in uneven application, and advise that seed be treated professionally to ensure uniform product coating and distribution. 

Also, recognize the limitations of a seed treatment: it will not prevent foliar diseases or Fusarium head blight (scab) development if conditions are favorable later in the growing season. In these cases, foliar fungicides would be needed for disease suppression. NDSU in its crop budgets for 2005 (www.ext.nodak.edu/extpubs/ecguides.htm ) notes that for wheat, “early season foliar fungicide would cost about $3-$5 and late season fungicide would cost about $9.50 plus application. Recent trials consistently show yield response of 5-10% with early season fungicide, if wheat planted into residue, and 15-20% with late application if weather favors disease development.”

The NDSU extension bulletin PP-447 “Seed Treatment for Disease Control” has more information on seed treatments, and can be found online at www.ext.nodak.edu/extpubs/plantsci/crops/pp447w.htm.  For more information on seed treatment product options registered for small grains and other crops, see the NDSU Field Crop Fungicide Guide online at www.ag.ndsu.nodak.edu/cropprod.htm. Growers are also encouraged to consult with their local agronomists and ag suppliers about product recommendations.

-----------------------------------------------------------------

MN Ag Dept Websites Offer Market Profiles, Export Info

The Minnesota Department of Agriculture has set up a website for those interested in learning more about the export trade: www.mda.state.mn .us/itrade/ Country market profiles from Canada, China, India, Japan, Mexico, South America and Taiwan enable exporters to learn more about what these countries import from the U.S.  Also, market profiles for corn, soybeans, wheat, beef, pork, dairy, and poultry provide export data on Minnesota’s major commodities. Although these profiles are general in nature, more in-depth research on consumer demand, products, pricing and transportation are available by request.

Another MDA link, www.mda.state.mn.us/ams/foods provides information for buyers or sellers to search the processed foods company directory. Information can be obtained based on product line, business classification, market segments and geographic markets.

With 96% of the world’s consumers and two-thirds of the world’s purchasing power outside the U.S., export markets are essential for farmers and for a profitable agricultural economy. Exports of food products are growing three times faster than sales in the U.S., and much of the MDA emphasis on trade development has centered on the promising regions of Latin America and Asia.

Value-added consumer food represents the fastest growing area of the U.S. export profile, according to the MDA. Minnesota ranks 7th among all agricultural exports states, with sales totaling $2.3 billion.