Skip Navigation

2/6/2012 - 2/12/2012

Commercial Pesticide Applicator Test Help Session

By Jim Fawcett, ISU Extension field agronomist

All commercial pesticide applicators must take exams in order to become initially certified and some choose to become re-certified by exam rather than by attending continuing instructional courses. With the increased interest in applying fungicides on corn and soybeans many commercial applicators are considering adding agricultural diseases (category 1C) to their certification.

A training session to help prepare individuals for the commercial pesticide applicator examinations will be offered in Marion on Monday, March 5 in the Linn County Extension Office at 3279 7th Ave. The session will run from 9 a.m. to 1 p.m. The Department of Agriculture and Land Stewardship will be giving tests for both private and commercial pesticide applicators in Marion on March 5 in the Linn Cooperative Oil Company at 325 35th Street from 10 a.m. to 2 p.m. and in Iowa City on March 6 at the Johnson County Extension Office, 3109 Old Highway 218 S., from 10 a.m. to 2 p.m.

The training session will cover the Iowa Core Manual and categories 1A (Agricultural Weed Management), 1B (Agricultural Insect Control), 1C (Agricultural Crop Disease Management), 3O,T, and G (Ornamental, Turf, and Greenhouse Pest Management), 4 (Seed Treatment) and 6 (Right-of-Way). Training on the Iowa Core Manual will be given for the first 2 hours, with the training on the other categories following.

There is a $25 fee per person for the training session. The session does NOT qualify as a continuing instructional course. For more information, please contact Jim Fawcett at 319-337-2145, Patrick O’Malley at 319-337-2145, or Virgil Schmitt at 563-263-5701.

Pesticide Applicators Test Preparation Sessions in Kossuth County

By Paul Kassel, ISU Extension field agronomist

Iowa State University Extension will sponsor a study session to prepare individuals to take Pesticide Applicator Certification exams. Anyone wanting to purchase and apply restricted use pesticides on land they own or operate needs a Private Pesticide Applicator Certification. A Commercial Pesticide Applicator Certification is required for those who apply pesticides for hire.

The exam study session will be held at the Kossuth County Extension office in Algona on March 8. The Kossuth County Extension Office is located at 1121-B Hwy 18 E, a half mile east of the Highway 18 and 169 intersection.

Private Pesticide Certification study sessions will begin at 1:30 and conclude at 2:30 p.m. The Commercial Pesticide Applicators study session will held from 3 to 5 p.m. The Commercial Applicators session will cover the Core Manual and the Ag categories (1A - Ag Weed, 1B - Ag Insect, 1C- Ag Disease or 4 - Seed Treatment).

Cost is $15 for either the Private or Commercial session. These training sessions do not qualify as continuing instructional courses. To pre-register, contact Carrie Gatton at 515-295-2469. Contact Gatton or Paul Kassel, at712-262- 2264, for more information.

Effects of Seed Treatments and a Soil-applied Nematicide on Iowa Corn Yields and Nematode Population Densities–2011

By Greg Tylka and Mychele Batista da Silva Department of Plant Pathology and Microbiology

Products that are currently available to manage plant-parasitic nematodes on corn in Iowa include the soil-applied insecticide/nematicide Counter® and two relatively new protectant seed treatments, Avicta® and Votivo®. Counter® is a contact and systematic nematicide with the active ingredient terbufos. Avicta® is a contact nematicide (active ingredient abamectin) that moves on the surface of the root, and Votivo® is a special strain of the natural soil bacterium Bacillus firmus that grows on the root. Counter® is available from AMVAC, Avicta® from Syngenta Seedcare, and Votivo® from Bayer CropScience.

Five experiments were conducted on ISU research farms in 2011 (figure 1) to assess and compare the nematode population densities and yields of corn growing in plots with and without the seed-treatment nematode protectants and the soil-applied nematicide Counter®.

Figure 1. Locations of the experiments in 2011.

The experiments were conducted at the Northwest Research and Demonstration Farm (near Sutherland), the Northeast Research and Demonstration Farm (near Nashua), the Johnson Research Farm (near Ames), the Armstrong Memorial Research and Demonstration Farm (near Lewis), and the Southeast Research and Demonstration Farm (near Crawfordsville). The fields where the experiments were conducted were selected arbitrarily – not because they were known to have damaging population densities of nematodes that feed on corn.

The treatments in the experiments were:
1. Avicta® Complete Corn (Avicta® + Cruiser® + Maxim® Quattro)
2. Cruiser® + Maxim® Quattro
3. Counter® + Cruiser® + Maxim® Quattro
4. Poncho® (500) / VOTiVO® + Acceleron® fungicides
5. Poncho® 500 + Acceleron® fungicides

Treatments 1 and 2 varied only by the presence of Avicta®, treatments 2 and 3 varied only by the presence of Counter®, and treatments 4 and 5 varied only by the presence of Votivo®.  The treatments were replicated four to six times in each experiment, and all treatments were applied to a single lot of seed of one 104-day corn hybrid. The experiment at the Armstrong Farm did not include treatment number 3, with Counter®.

Soil samples were collected from each plot to determine nematode population densities at or near the time of planting and again when the corn was at the V5 to V6 corn growth stage. Root samples also were collected at the V5 to V6 corn growth stage and nematode population densities inside the roots were determined. The plots were harvested and yields were calculated for each treatment.

ISU Extension field agronomists Terry Basol, Joel DeJong, Jim Fawcett, Mark Licht and Aaron Saeugling; and ISU research farm staff Kent Berns, Stephanie Marlay, Ken Pecinovsky, Ryan Rusk, Josh Sievers and Kevin Van Dee established, maintained and harvested the experiments and collected the nematode samples.

Nematode results

  • There were no significant differences in numbers of plant-parasitic nematodes in the soil among the treatments at planting in any experiment or in the soil at the V5 to V6 corn growth stage in the experiments in northeast, southeast, and southwest Iowa.
  • In the experiment in central Iowa, there were significant differences in total number of plant-parasitic nematodes in the soil among the treatments at the V5 sample date, with fewer total nematode numbers in the Counter® and Votivo® treatments (figure 2).
  • In the experiment in northwest Iowa, spiral nematode numbers and total numbers of plant-parasitic nematodes in the soil were lower in the treatments with Avicta®, Counter®, and Votivo® and the Cruiser® + Maxim® Quattro treatment (minus Avicta®) than in the treatment with Poncho + Acceleron fungicides (minus Votivo®) (figure 3).
  • The numbers of spiral, root-lesion, lance, dagger and pin nematodes in all experiments at planting and at the V5 to V6 corn growth stage were well below established damage thresholds for those nematodes.
  • Very few nematodes were recovered from the root samples; those data were not used.

Corn yield results

  • There were no significant differences in yield among the treatments at any of the five experiments.
  • Overall mean yields for the experiments were 195 bushels per acre in northwest Iowa, 205 bushels per acre in northeast Iowa, 151 bushels per acre in central Iowa, 154 bushels per acre in southwest Iowa, and 129 bushels per acre in southeast Iowa.
  • Corn yields were low in central, southwest and southeast Iowa experiments. There was some hail damage and gray leaf spot developed in the experiment in southwest Iowa. In the experiment in central Iowa, there were wind lodging problems later in the season, possibly related to poor stalk health.

The nematode management products did not consistently reduce numbers of plant-parasitic nematodes or corn yields in the experiments that were conducted in 2011.

The low population densities of plant-parasitic nematodes that were present in the field did not affect corn yield in the experiments. The numbers and types of nematodes in the experiments were similar to those frequently found in samples submitted to Iowa State University for testing for nematodes that feed on corn from 2000-2010 (see ICM News article).

The nematode management products may have a much more pronounced beneficial effect in fields with very damaging nematode species (like needle nematodes) and in fields with much greater plant-parasitic nematode population densities.

For more detailed information about the methods used and results of the experiments, contact the first author or consult the 2011 annual reports of the ISU Research and Demonstration Farms.

Figure 2. Mean number of plant-parasitic nematodes in soil samples collected at the V5 corn growth stage in the experiment in central Iowa (near Ames) in 2011. “misc.” = miscellaneous plant-parasitic nematodes present in very low numbers. Bars with different letters above them had significantly different total numbers of plant-parasitic nematodes (P=0.10).


Figure 3. Mean number of plant-parasitic nematodes in soil samples at the V6 corn growth stage in the experiment in northwest Iowa (near Sutherland) in 2011. Bars or segments of bars with different letters are significantly different (P=0.10).


Greg Tylka is a professor with extension and research responsibilities in management of plant-parasitic nematode. Mychele Batista da Silva is a graduate student in the Department of Plant Pathology and Microbiology at Iowa State University.

Spring Seed Cover Crops to Help Recover Flooded Fields

By Paul Jasa, University of Nebraska-Lincoln Extension engineer

There was considerable flooding along the Missouri River in the summer of 2011, leaving many fields scarred and bare, without a crop. Producers should make field repairs as needed and seed a cover crop to help protect the soil and start rebuilding soil life before the 2012 cropping season. Cover crops benefit flood-damage soils in several ways.

  • The residue from the cover crop will protect the soil from raindrop impact, reducing soil erosion and crusting.
  • The upright cover crop residue will keep the wind and sun off the soil surface, reducing wind erosion, sandblasting, and soil water evaporation.
  • The growing roots of the cover crop will help feed the soil biological life, especially arbuscular mychorrhizae fungi.

Crop Selection and Seeding Rates
Cool season cereal grains are fast growing in the spring, provide standing residue fairly quickly, and are easy to kill before seeding the cash crop. Consider seeding oats, barley, triticale, cereal rye, or wheat (listed in order of preference, depending on seed availability) at a rate of one to two bushels per acre. Use the seeding date typical for seeding oats in your area, usually when the soil temperature is above 35°F and rising.

Cover crop cocktails, a mixture of several species and plant types, provide different rooting patterns and varying plant architecture to add diversity to the system. The diversity is valuable for restoring microbial and physical soil function. Mixtures also provide good soil cover across a variety of conditions since cover crop types respond differently to varying soil and weather conditions. Several cool season legumes, brassicas, or other broadleafs could be seeded with the cool season cereal to aid in soil life recovery. The seeding rate of the cereal grain should be reduced about 50% if another cover crop is seeded with it.

A legume like spring forage peas (30 lb/ac) or common vetch (10 lb/ac) could be seeded with the cereal grain to fix some nitrogen, improving the cover crop benefits. Producers should use twice the recommended amount of the proper inoculant for these legumes as the native rhizobia bacteria were probably reduced during flooding. Taller cool season brassicas and broadleafs like rapeseed (3 lb/ac), mustard (3 lb/ac), flax (5 lb/ac), or Ethiopian cabbage (2 lb/ac) also could be added to the cereal grain and legume seed mix to further improve the soil system. These cover crops stand nicely to help reduce wind erosion and have a vigorous tap root to help penetrate the soil. If you’re adding several of these other cover crops to the mix, the seeding rates of each could be reduced some.

Seeding Methods
For most effective cover crop seeding, use a drill or air-seeder to place the seeds directly into the soil, about 1½ to 2 inches deep. Both provide some soil smoothing and cut up some of the surface debris. If the drill or air-seeder is equipped to apply fertilizer, some starter fertilizer could be applied to help cover crop establishment. Another option would be to apply fertilizer for the following cash crop when seeding the cover crop. Compaction will be less than with tillage as most drills and air-seeders are pulled with smaller tractors than those needed for tillage equipment of the same width. In addition, the seed metering, seed distribution, seeding depth, and seed-to-soil contact will be more uniform than broadcast seeding, providing a better cover crop stand, especially at lower seeding rates.

Broadcast seeding followed by a light tillage operation may be an option for some producers, especially if some tillage is needed to deal with erosion, scouring, or sedimentation. Most producers have access to a dry fertilizer applicator which could be used to distribute the cover crop seed. Depending on fertility needs, the seed could be mixed with dry fertilizer to accomplish two things in one trip while improving seed distribution. The light tillage with a spike-tooth harrow, Aerway, coulter tillage tool, or similar fluffing harrow would incorporate the fertilizer and provide some seed-to-soil contact and some smoothing of the soil surface.

If the soil is dry enough, tillage with a disk or field cultivator could be performed to level the soil surface and better incorporate larger seeded cover crops, but compaction and soil smearing is a risk if the soil is wet. Depending on the soil moisture situation and the depth of tillage, the broadcast seeding rates should be increased by 50 percent compared to drilling.

Terminating the Cover Crop
While many cover crops are most effective if they have 45 to 60 days of growth before termination, producers should kill them at an appropriate time so as not to affect the next crop. If the spring looks like it will be a dry one, the cover crop should be killed several weeks before planting so as to conserve soil moisture. While it may seem like not a lot of biomass was produced, the roots of the cover crop still helped the soil biology, benefiting the soil system. If the spring will be wet or the soil needs dewatering, the cover crop could be allowed to grow longer for more biomass production and more benefits for the soil system.

Producers should check with their crop insurance provider and the local FSA office for guidelines and restrictions related to cover crops. For maximum soil benefit, the cover crop should not be grazed, hayed, or tilled and the next crop should be no-tilled into the cover crop residue.

Clarke McGrath, ISU Extension, was an article reviewer.

Paul Jasa is an extension biosystems engineer with the University of Nebraska-Lincoln. He can be contacted at 402-472-6715 or by emailing Clarke McGrath is a program specialist with Iowa State University Extension. He can be contacted at 712-215-2146 or by email at

This article was published originally on 2/13/2012 The information contained within the article may or may not be up to date depending on when you are accessing the information.

Links to this material are strongly encouraged. This article may be republished without further permission if it is published as written and includes credit to the author, Integrated Crop Management News and Iowa State University Extension. Prior permission from the author is required if this article is republished in any other manner.