Last year, a series of fact sheets about soybean rust were developed. Those fact sheets have undergone major revisions to provide additional information that has been requested. Fungicide Application Technology for Soybean Rust-2006 is avaiable as a pdf at: http://www.ipm.msu.edu/cat06field/pdf/sbr_aptechnology.pdf

The keys to successfully using fungicides to control soybean rust are applying the fungicide at the right time, achieving good canopy penetration and good leaf coverage. The fact sheet gives guidelines for selecting the correct spray volume, droplet size, ground speed, nozzle pressure, boom height and nozzle type to achieve good penetration and coverage of the soybean canopy.

For wheat growers, deciding whether or not a fungicide application will be needed to control Fusarium head blight (FHB) and associated levels of DON (vomitoxin) can be difficult. Major outbreaks of Fusarium head blight are associated with specific weather patterns prior to flowering of the wheat crop. Some of you may have used weather-based models in the past as a decision making tool. Models can be useful if you work within their limitations.

The Penn State Model helps growers assess the risk of FHB in their region. This model predicts the risk probability of an epidemic with greater than 10% severity based on observed weather patterns. This year, Michigan will be participating in a pilot program along with four other states to add comments that are outside what the model might be showing. The added information will include wheat growth stages, weather patterns and information about wheat diseases being found in the state in addition to FHB.

The new system should be up and running by the first week in May. The web address for the Penn State Model model is: http://www.wheatscab.psu.edu/riskTool.htm

Soybean aphid chemical control: foliar sprays
Christina DiFonzo
Entomology

General lessons from many trials in 2005
§      Scouting pays: Soybean aphid (SBA) problems were detected early by scouting and variability in infestation (and need for treatment) was also noted.
§      Residuals differ: OPs tend to have better initial kill but shorter residual. Pyrethroids tend to have longer residual.
§      Yields often don’t differ: In the end, however, yield generally depends more on spraying itself, then on choice of insecticide.
§      Coverage counts: Coverage probably explains many of the performance problems with various insecticides.
§      Tank mixing: Tank mixes of pyrethroids with Lorsban did not improve yield.
§      Reduced rates: Reduced rates of insecticides did not provide adequate control or improve yield.

MSU Recommendation
§      Do scout fields more than once, beginning in mid-June;
§      Do use a threshold of 250 SBA per plant with increasing aphid populations, through the R5 plant stage [in practice: nearly every plant has aphids, aphids cover the top leaves of the plant, and may be moving to the stems]
§      Do use a full rate of an insecticide;
§      Do optimize coverage = 40 psi, at least 20 GPA, nozzles recommended for insecticides;
§      Do not tank-mix reduced rates of several products.

The 2005 field season was a great year to test foliar sprays for soybean aphid control. Below I summarize the results of several trials comparing insecticide sprays to untreated plots. Please note that some of the products in the trials are not currently registered for soybean. Table 1 shows a complete list of products tested in our trials, plus information on chemistry, manufacturer and registration on soybean.

Efficacy trials were done at the Saginaw Valley Bean and Beet Farm in a field planted on May 5 and at the MSU Campus Farms in fields planted on May 17 (Entomology) and in mid-June (Botany). At all locations, treatments were made when SBA populations crossed the threshold of at least 250 SBA per plant, using 23 GPA, 40 PSI and Twinjet nozzles. The field at the bean and beet farm was sprayed on July 14 in the R2 plant stage at an average aphid population of 830 SBA per plant. Aphid counts were taken 4, 7, 14, and 21 days after treatment. The field at the MSU Entomology Farm was sprayed on July 27 in the R4 plant stage at an average aphid population of 356 SBA per plant. Aphid counts were taken two and seven days after treatment. The field at the MSU Botany Farm was sprayed on July 20 in the V4 plant stage at an average aphid population of 372 SBA per plant. Aphid counts were taken 5 and 14 days after treatment.

Table 2 summarizes insecticide rankings at various days after treatment (DATs). Treatments were included in the table only if they were done in at least two of the three trials. Counts from the MSU Entomology Farm (2 and 7 DAT) and Botany farm (5 and 14 DAT) are reported together, since the fields were adjacent.

At the MSU Farms, treatments including Lorsban knocked aphids back quickly (white cells, 2 DAT). But within five to seven days, several of the pyrethroid and nicotinoid treatments (Assail, Proaxis, Warrior) had the lowest aphid counts, an effect of residual kill. By 7 DAT, some treatments were back over threshold and by 14 DAT many plots were near or over 1,000 SBA per plant. The effect of residual is clear by 14 DAT; plots sprayed with shorter-residual products (Lorsban, Orthene) had over 1,000 SBA per plant (black shaded cells), while plots sprayed with longer-residual insecticides (some pyrethroids and nicotinoid) had fewer aphids (dark gray-shaded cells). In late July through early August, a large number of winged aphids landed in soybean at MSU, and fields were re-infested quickly. This made it very challenging to maintain aphid control.

In contrast to the challenges at the MSU Farms, insecticides worked well at the bean and beet farm. Even by 14 DAT, SBA numbers were still under 100 SBA per plant in most treatments (light-gray shaded cells), compared to nearly 2,000 SBA per plant in the untreated check. By 21 DAT there was over 2,800 SBA per plant in the untreated check. However, most treated plots were still below 250 SBA per plant (Table 2 medium-gray shaded cells). The treatments over threshold have known shorter residual. Table 2 clearly shows this difference in residual. This table shows the aphid populations in treatments sprayed with insecticides currently registered on soybean. At 4, 7 and 14 DAT, all treatments still had less than 250 SBA per plant. By 21 DAT, treatments were separating out by residual: the OPs Orthene, Lorsban, or a tank mix of Lorsban with Baythroid all had over 250 SBA per plant, while the longer lasting pyrethroids remained under 250.

Rank: For each date, treatments are ranked from fewest SBA per plant (1) to the highest. If counts were close, within a few aphids of each other, the treatments were tied.

A star* indicates that the aphid population is significantly less than the population in the untreated check.

At the entomology farm, the top two treatments (Asana, Assail) clearly yielded significantly better than the untreated check. Most of the remaining treatments were somewhere in the middle, between the best yielding treatments and the untreated check. Two treatments, Trimax and a low rate of Baythroid, actually yielded less than the untreated check. This study was sprayed on July 27. Recall that the next week, large numbers of winged aphids landed at this location, and fields were re-infested quickly. This may account for the wide variation in yield.

At the bean and beet farm all treatments yielded better than the untreated check. The top 11 treatments had similar yield. Only Trimax yielded less than the others, but it still yielded better than no spray. In the end, the important thing appears to have been getting an application on at the right time, rather than choosing a particular product. In Table 3, the insecticides currently registered on soybean are Asana, Baythroid, Lorsban, Orthene, Proaxis, and Warrior. Yields for these six products were not different from each other, ranging from 49 to 53 bu/acre compared to 39 bu/acre in the untreated check.

There are now two new seed treatments registered for soybean. Cruiser (thiamethoxam) was available in 2005; Gaucho (imidacloprid) can be used in 2006. Soybean seed can be ordered already treated, or treated by a commercial outfit after purchase. In most cases, insecticide-treated seed will also be fungicide-treated. The prices we were recently quoted for Cruiser and Gaucho treated seed were between $9 and $12 per unit (50 lb bag) = $10 to $14 per acre.

Cruiser and Gaucho protect seeds in the ground from early season insect pests, such as seedcorn maggot and wireworm. Both products may have an impact on grubs, although grub control is not listed on either label. Both products are also systemic. The active ingredient moves up into the plant as it grows, protecting foliage from insect feeding for approximately 30 to 40 days. Bean leaf beetle is one target for the systemic action. Bean leaf beetles overwinter as adults, and the adults emerge in the spring to feed on small soybean plants. First generation bean leaf beetle feeding is usually not a concern in Michigan, but there may be areas in southern Michigan with isolated problems. Another obvious target for seed treatments is the soybean aphid. Early season aphid colonizers from buckthorn probably deposit nymphs on treated bean leaves (they likely cannot detect treated beans), but the nymphs themselves do not survive. This delays colonization of the field by several weeks.

Eventually, as the plant gets larger and the insecticide breaks down, the dose of insecticide in the plant is no longer lethal. At that point, aphids feeding on treated beans get a sub-lethal dose of insecticide; research from the University of Minnesota shows that aphids have fewer nymphs on seed-treated beans. But these aphids may not die. Populations on treated beans can still go over threshold when populations are heavy, although the number of aphids per plant may remain less than untreated beans.

From an economic standpoint, Cruiser and Gaucho treatment is an insurance policy, not an IPM-based strategy. When soybean aphid isn’t present or numbers are low (as in 2004), seed treatments generally do not yield any more than untreated beans (see Table 1). As insect pressure increases, Cruiser and Gaucho will protect yield from early season aphid feeding, but if the outbreak continues, seed treatments wear out. You may need to spray seed-treated fields later in the season. Cruiser and Gaucho might be more useful on early-planted beans in areas with heavy overwintering populations of soybean aphid (for example, southeast Michigan). In outbreak years, these fields are colonized early by aphids, when a lethal dose of insecticide is still in the plant. Over the long-term, you probably are better off with a well-timed, scouting-based foliar spray made only if fields are over threshold. In years with low aphid numbers, you essentially preserve $10-$12 per acre in profit by not spending money on aphid control.

Targeting the use of seed treatments may be possible if researchers can predict aphid outbreaks using, for example, the regional suction trap network set up in 2005. But for now, we do not have a reliable way to predict the need for seed treatments next year. The bottom line is to understand what seed treatments will do for you, what insects they control and how long they last. Also remember to scout seed-treated fields as well, because they may need to be treated in outbreak years.

Table 1 summarizes three years of fieldwork with seed treatments at MSU, under varying aphid pressure.

In 2003, cages were used over small plots to generate high aphid pressure. SBA first survived on treated plants 37 days after planting. Seed treated plants went over threshold two weeks later (July 28) than untreated plants (July 14), but aphid numbers on both untreated and treated plants increased rapidly into the thousands. No yield was taken from the small cages.

In 2004, small plot studies were done under natural aphid pressure. Aphid numbers were extremely low throughout the field season. Neither treated nor untreated plots approached threshold, and yields did not differ significantly. Using a seed treatment as “insurance” would not have paid economically in 2004.

In 2005, aphid numbers were higher than in 2004. At two locations on the MSU campus, Gaucho was included as a treatment. In both studies, Gaucho protected beans from aphids for two additional weeks compared to the untreated beans, but it started to run out by 35 days after planting. Untreated and Gaucho-treated plots went over threshold the same week, or shortly thereafter, and aphid numbers increased to moderate levels. By the end of the season, yields did not differ significantly between untreated (56) and Gaucho (61) treated plots. However, when the Gaucho treated plots were sprayed with Trimax (= imidacloprid, not yet registered on soybean), yield improved significantly over the untreated check to 68 bu/ acre, equaling the best foliar treatment in the same field (Asana, also 68 bu/acre)

In a study that included Cruiser at the MSU Bean & Beet Research Farm, aphid populations were tremendous, reaching nearly 17,000 soybean aphid per plant in early August. Treated and untreated plots went over threshold the same week. Cruiser suppressed aphid numbers by about 30% compared to the untreated, and increased yield significantly. However, a single well-timed spray of Warrior (37 bu/acre) outyielded the Cruiser treatment (30 bu/acre). At this location, SBA pressure was so high that it also paid to apply Warrior to Cruiser treated beans (50 bu/acre).

In summary, in years with low aphid populations, we do not see a yield gain (in the absence of other pests) from using a seed treatment. Under heavy aphid pressure, seed treatments do protect yield, but usually will not outperform a single foliar spray timed at 250 SBA per plant. Seed treatments begin to run out after 30-40 days, just as aphid pressure typically increases in most locations in Michigan. However, applying a foliar spray to seed-treated beans over threshold can result in additional yield. In the end, it’s a matter of pushing the pencil, figuring the cost of seed treatment vs. spraying vs. doing nothing over a time frame of several seasons. Eventually, researchers hope that aphid numbers in fall suction trap catches may be a great help in making a decision to use a seed treatment the following year.

High fertilizer prices got you down? A newly reformatted worksheet from Michigan State University Extension (MSUE) may help.

The Manure Haul Spreadsheet, introduced in the early 1990s, has been updated to help producers figure the cost of hauling manure to fields farther down the road, a practice that may take the sting out of high nitrogen prices.

“When nitrogen fertilizers were less expensive, 3 miles was about as far as you could afford to haul manure before the cost of transportation began to outweigh the value of the fertilizer,” says Bob Battel, farm management educator for Michigan State University (MSU). “But the high cost of commercial nitrogen may mean that you can go farther down the road and still save money, even after you factor in the increased cost of fuel.”

Battel recently updated the MSU Extension Manure Haul Spreadsheet to aid producers who want to determine the feasibility of fertilizing more fields with manure. Farmers with access to Microsoft Excel can download the information from the MSUE Web site. From there, they can enter information that will personalize the data output and make it pertinent to their farms.

“Farmers who take the time to enter personalized information will get the most benefit from the program,” Battel explains. He says a number of data points are requested, including current price of fertilizers, labor costs, distance to the field and type of crop to be fertilized.

“Two variables that really extend the distance you can haul are the size of the tank you’re hauling with and the speed of travel,” Battel says. “Farmers may find that it pays to hire a custom hauler with a large tank who can move faster rather than do all the hauling themselves.”

Though standard manure nutrient values are already programmed into the software, Battel says a recent manure analysis will make the figures more accurate.

“We used standard book values for manure in the spreadsheet, but they are often unrealistic and could skew the values substantially,” Battel says. “To get the most accurate results, you should have a current manure analysis.”

A link to the Manure Haul Spreadsheet appears in the upper right corner of www.rootzone.msu.edu Farmers who want to learn more or don’t have access to Excel can call their county MSU Extension office for more information.

Submitting samples to MSU Diagnostic Services
Accurate diagnosis depends on the rapid receipt of fresh and representative samples along with pertinent information relating to the problem. A completed submittal form should accompany all samples. Submittal forms are available at MSU Diagnostic Services or your local Extension office. Submittal forms can also be downloaded from www.pestid.msu.edu. Samples can be dropped off at our reception area between 8 a.m. and 5 p.m. or shipped overnight delivery by U.S. mail, FedEx, or UPS. To preserve the quality of the sample, do not package samples in envelopes. Also avoid mailing samples on Friday.

Submit samples to:
Michigan State University
Diagnostic Services
101 Center for Integrated Plant Systems
East Lansing, MI 48824-1311
Phone: (517) 355-4536 Fax: (517) 432-0899

Seedlings: Carefully dig seedlings from the field. Gently rinse the soil off of the roots and wrap the plants in dry paper towel or newspaper. Ship in small box, not an envelope.

Leaf spot and fruit rot: Send several affected samples representing the early and moderate stages of the symptom progression.

Herbicide injury: Submit both injured and apparently healthy crop plants. Plants should be dug carefully from the soil so roots, if injured, will remain intact. Roots and soil should be placed in a plastic bag, pot, or small bucket to prevent soil from touching the foliage. A pint of soil from both “good” and “bad” area should also be submitted. Any patterns in the field should be noted on the submittal form, along with past crop and pesticide history.

Woody plant identification: Submit a large section of the terminal end of the stem or branch. Where possible, include any flower or fruiting structures, roots, and leaves. Leaves may be pressed flat between paper or cardboard to prevent crinkling. Woody plants may be wrapped in plastic to retain moisture.

Herbicide resistance: Weeds will be screened for herbicide resistance using one of several techniques. Typically, a whole plant pot assay established from seed will be our standard test for resistance confirmation. Mature, high quality seed or seedheads should be collected from suspicious plants in late summer or fall and submitted in a paper bag. Do not seal in plastic. Screens will be designed by herbicide site of action (ie: ACCase inhibitors, ALS inhibitors, Photosynthesis inhibitors). Other resistance confirmation tests may be utilized but will depend upon weed species, herbicide, and mechanism of resistance. Extensive tests include but are not limited to: petri-dish germination, chlorophyll fluorescence, leaf disc flotation, and enzyme sensitivity assays, as well as molecular diagnostic testing.

Always store nematode samples in plastic bags or other containers that retain moisture. Submit a pint to a quart of soil.

Problem diagnosis: Collect soil & roots (or foliage) from the margins of diseased areas. Submit samples of diseased plants and apparently healthy ones.

Problem avoidance: Collect soil & roots (if available) by walking a zigzag or w-shaped pattern. The more sub-samples (soil, cores, probes, etc.) collected the “better” the sample.

Moths/butterflies: Place specimens in the freezer for half an hour to kill them and gently pack in a small box or vial with tissue paper.

Ants/Other Adult Arthropods: Ant specimens should only include worker ants (i.e. those without wings). Submit all specimens in alcohol. Other adult and hard-bodied specimens: Submit in alcohol.

Larvae (caterpillar, grub, maggot, etc.): Whenever possible, soft-bodied larvae should be lightly boiled for a few minutes before placing them in alcohol. This prevents the specimens from shriveling and becoming discolored, however it only works if the larvae are alive when dropped in the boiling water.

Pesticide analysis samples
Soil, water, and plant vegetation can be tested for the presence of pesticides using appropriate analytical instruments and techniques. Pesticides will be tested on an individual basis or, if available, in multi-pesticide screens. Samples should be submitted in leak-proof, glass containers and kept cold or frozen until arrival.

Services and fees for MSU Diagnostic Services
Note: Fees for out-of-state samples are higher. Contact laboratory for pricing.

Plant Health Analysis
§      Visual inspection for infectious and non-infectious diseases, insect injury and herbicide injury; pathogen culturing; pH and soluble salts: $20.00
§      INSV / TSWV ELISA tests: $20.00
§      Bacterial ID (BIOLOG™): $25.00
§      Special laboratory analysis: *

Weeds/plants
§      Common plant ID: N/C
§      Keyout plant ID: $10.00
§      Herbicide resistance in weeds
§      Standard test:
§        - Single site of action $50.00
           - Each additional site of action $20.00
§      Extensive test: *
§      Special identification/diagnosis *

Nematodes
§      Basic nematode analysis: $20.00
§      Total nematode community analysis: $50.00
§      HG Type testing $50.00
§      Verticillium analysis
          - Wet sieving: $20.00
          - Dilution plating: $15.00

Insects/arthropods
§      Common insect ID: N/C
§      Keyout insect ID: $10.00
§      Special identification/diagnosis *

Pesticide analysis
§      Individual pesticide tests/ multi-pesticide tests
      - Water: $90.00 / $125.00
      - Vegetation: $100.00 / $150.00
      - Soil: $125.00 / $175.00

* Variable costs requiring client approval. Contact laboratory for pricing.

Regional reports
1 -- Southeast
Ned Birkey

Weather
The weather is finally nice with more normal temperatures. Soil temperatures are currently in the high 30s, though have been in the low and mid-40s even last weekend. After a very snowy December, the rest of the winter saw predominantly rain. Because last summer was hot and dry, the soil has needed the moisture recharge and many tile lines are not running.

Commodity reports
Alfalfa is just starting to green up. There has not been much frost in the ground this year so there is not much heaving. Chickweed has had a great winter and seems to be in many thin places.

Corn acreage is expected to be down because of the high cost of fuel and fertilizer. The ethanol plant at Riga is expected to be up and running by year-end.

Soybean acreage is expected to be higher because this crop is “cheaper” than corn. Sales of fungicide and insecticide treated seed are significantly higher this year. With aphids coming in early June last year, some insecticide treated soybeans had some residual benefit for the very early aphids. A soybean biodiesel plant at Milan may be up and running by summer.

Wheat has finally greened up this past weekend. Many farmers have been worried about their fields because they have stayed dormant for so long. It is still too early to assess stands, though many fields have not had major flooding or ponding problems with the winter snow and rains. Most fields were planted on time last fall and appear to have overwintered in good condition.

An area of low pressure over the central Great Plains region Thursday morning (April 6) will slowly move eastward towards the Ohio Valley during the next 24-36 hours. This will set the stage for widespread rain and snow across central and southern sections of Michigan. Precipitation will begin as rain in southwestern sections of the state late Thursday and spread northeastward to much of southern and central Lower Michigan by Friday morning. A few thundershowers will be possible in southern sections. High pressure over southern Canada will feed cold, dry air into the state on brisk northeasterly winds Friday, keeping northern sections of the state dry and gradually changing precipitation in central sections over to snow before ending Friday evening. Some locations in central Lower Michigan could see several inches of heavy, wet snow accumulate by late Friday evening.

Water equivalent precipitation totals with this system are forecast to generally range from 0.5 to 1.0 inches in southern and central areas, tapering to less than 0.10 inch in the northern Lower Peninsula. The Upper Peninsula will likely remain dry. Fair and cool weather is expected statewide beginning Saturday and continuing into the middle of next week. Temperatures will fall back from highs mainly in the 50s Thursday to increasing to daytime highs from the 40s north to low 50s south. Low temperatures will generally fall back to the 20s through Sunday. Another area of low pressure is forecast to approach the region by late Tuesday or Wednesday of next week, bringing the next chance for precipitation to most of the state.

Further ahead, medium‑range forecast guidance suggests the formation of a troughing feature across western sections of the United States with southwesterly flow aloft across the Midwest. This pattern would suggest warmer than normal temperatures and the possibility of severe weather across the region. (2006 has been a very busy season for severe weather thus far.)

The official NOAA 6-10 day and 8-14 day outlooks (covering April 11-15 and 13-19) both call for above normal temperatures across Michigan and much of the eastern United States. Precipitation is forecast to range from near normal levels across the southeastern one half of the state to above normal levels in the northwest.

Latest NOAA CPC long lead outlooks for Michigan have shifted towards a wetter forecast during the next couple of months. The official 1-month and 3-month long lead outlooks for the month of April and April to June periods call for the increased likelihood of above normal precipitation in Michigan and the Upper Midwest. Mean temperatures for both April and the 3-month April to June period call for the equal odds scenario of below-, near-, and above-normal values. As a result, while it is a good rule in any Michigan spring, it may be even more important than normal to take full advantage of any fieldwork opportunities as they develop in the coming weeks.