Central Minnesota’s Walking Your Fields newsletter-July


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DuPont Pioneer agronomists talk about soybean aphids, fungicide applications, weed resistance and corn rootworm pressure in this July issue of Walking Your Fields newsletter.

Articles are written by DuPont Pioneer agronomists in Minnesota and are distributed on behalf of DuPont Pioneer account managers and Pioneer sales reps.

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Central Minnesota’s Walking Your Fields newsletter-July

  1. 1. The Good: Since last issue, crops have made some re- markable advancements due to warm and sunny weath- er. Many fields have turned from yellow to green which is a good sign that roots must have gotten into the “grocery store” (fertilizer) and are responding. The Bad: Many fields that were caught in the May 25 – June 5 period that received from five to 11 inches of rainfall have struggled due to water logged conditions. The Ugly: Uneven, satu- rated areas of fields need some drier weath- er so roots can estab- lish proper- ly. Roots need oxy- gen to de- velop and move down- ward. Side dressed nitrogen would also help to salvage the season in those areas of anemic, yellow colored corn. It is not too late to apply 10 -15 gallons of 28 or 32% liquid nitro- gen with a high boy applicator with drip tubes to keep the solution from burning leaves. Soils with low organic matter levels and water satu- rated fields will benefit from planned or rescue top dressing of nitro- gen and sulfur. Typically the big- gest response oc- curs when applica- tions are done be- fore the corn is 12- 18 inches tall. However, weather conditions forced some later applica- tions this year. Of- ten 30-50 pounds/ acre of supple- mental N is ade- quate to offset lost nitrogen. GDU and Precipitation Updates. Visit www.Pioneer.com for the latest agronomic and weather information. Click on the “Agronomy” tab and look for the GDU or Precipitation calculator tab. Type in your town or zip code for local data. This website has a wealth of agronomic information right at your finger tips. If you need help navigating in this site, contact your local Pioneer® sales rep or account manager. The information in the table above is from our Pio- neer.com GDU calculator. We used May 1 as the starting point. Of course if you planted earlier, your crop is further along than indicated. GDU wise, we are not doing all that badly. With our new Pioneer® Field360™ Select, you can play out scenarios where the calculator will actually peg maturity for each of your mapped fields based on planting date and using the average growing degrees so far this season, it will estimate when each Pioneer® brand hybrid you planted will be physiological mature (PM). Once pollination occurs, PM will be roughly 55-60 days later. Pollination is right around the corner. Excessive heat (especially high nighttime temps) can be detrimental to kernel development and ear fill. WALKING YOUR FIELDS® newsletter is brought to you by your local account manager for DuPont Pioneer. It is sent to customers throughout the growing season, courtesy of your Pioneer sales professional. The DuPont Oval Logo is a registered trademark of DuPont. Asana® XL and Assure® II are trademarks of DuPont. PIO- NEER® brand products are provided subject to the terms and conditions of purchase which are part of the labeling and purchase documents. ®, TM, SM Trademarks and service marks of Pioneer. Authority® is a registered trademark of FMC Corporation. Flexstar® is a registered trademark of Syngenta Crop Protection. © 2013 PHII. Summer Marches Along: Crop Progress WALKING YOUR FIELDS ® www.pioneer.com July 24, 2013 - Issue 4 Table 1. Growing Degree Units (as of 7/15/13) Location Precip Depart from Norm Since 4/1/13 GDD Totals Since 5/01/13 GDD Depart from Norm Montevideo -1.97 1145 -55 Hutchinson -0.53 1151 +57 Olivia +0.44 1125 +20 Willmar -2.16 1254 +147 Lamberton +5.88 1160 +12 Marshall -1.96 1168 +26 Redwood Falls -0.19 1171 -73 Worthington -0.07 1130 0 North Mankato +0.95 1172 -25 Waseca +7.06 1022 -126 Winnebago +3.52 1173 -18 www.Pioneer.com Photo: DuPont Pioneer Nitrogen and sulfur topdressing were criti- cal this year with the excess precipitation. Photo: Clyde Tiffany, DuPont Pioneer
  2. 2. Goss‟s wilt is showing up again in corn fields across the central U.S. In 2012, the disease was found throughout much of the area despite the dry conditions in late sum- mer and fall. Luckily, incubation was not severe with the drought keeping pressure in check. The prolonged wet weather this spring is conducive to bacterial dis- eases in many crops, and corn has been no exception. Goss‟s wilt is caused by a bacterial patho- gen and doesn‟t respond to treatment with fungicides. It is best managed with resistant hybrids and sound cultural practices like crop rotation and more aggressive tillage. Signs and Symptoms of Goss’s Wilt  Long, water-soaked, grayish-green patches or streaks that turn to large dead streaks with wavy margins  Dark „freckles‟ within or just outside of leaf lesions  Lesions appear to spread along leaf veins (characteristic of bacterial disease)  Yellow-orange bacterial ooze (or dried ooze appearing as shiny flecks)  Stems may become plugged with bacteria, vascular bundles appearing orange to brown. The disease generally starts from inoculum surviving on previous (corn) crop residues, found at or near the soil surface. Early-season rainfall, especially when heavy or associated with high winds, can lead to infection of the young corn crop. Early infection can produce the most devastating symptoms, including wilting and early plant death. Later infections typically affect leaves primarily, but may lead to early maturity, or reduced ear size and lower yields depending on the area affected and time of symp- tom onset. Fungicide applications on hail damaged plants are only recommended if there are significant fungal diseases pre- sent. Fungicides are effective tools for protecting yield potential of plants if significant disease levels are present but do not improve the yield potential of crops. Other pos- itive yield responses result from hybrid susceptibility and previous crop history (corn on corn) and tillage practices. Soybean aphids are right on schedule and are being re- ported in parts of southern Minnesota. Even if you plant- ed soybean seeds treated with a nicotinoid insecticide to delay aphid population establishment, you will still want to scout your fields for this pest from V5 through R5. Symptoms. Aphid-infested soybean plants may look sim- ilar to a potassium deficiency: curled leaves, often yellow on the outside. Aphids produce a sugary excrement, known as honeydew, on leaves, which promotes soot mold growth and can serve as a feeding ground for ants. Plants infested by the soybean aphid will also appear shorter. Take Action. Count the number of aphids on 30 to 50 plants throughout the entire field and calculate the aver- age number of aphids per plant. If aphid populations reach 250 per plant and are increasing during the R1 – R5 growth stages, consider a foliar insecticide to control the population. DuPont™ Asana® XL insecticide is a proven insecticide that gives good residual protection against aphids. Your local authorized Pioneer sales rep can help with product recommendations. There are also several beneficial insects that feed on soybean aphids and can naturally control them as well. We have seen an assortment of carryover issues on soy- beans earlier this spring due to the dry 2012 season where herbicides did not break down. Most of issues have been resolved with more adequate rainfall in 2013, but some yield reduction is still a possibility. Weed Resistance. More growers are reporting difficult to control weeds. When we observe waterhemp plants sur- viving 40 ounces of glyphosate and 12 ounces of Flexstar® herbicide that raises a red flag. What herbicide options remain for these larger weed species? You may not like the answer, but cultivation is still a viable option if all other avenues of weed control have failed. You must start using some kind of pre-emerge program in 2014. Those of you who have been using pre-programs are reporting very good to excellent control with few weed escapes and resistance is- sues. The picture here shows the value that a pre- emerge herbi- cide can provide in combatting waterhemp and other difficult to control weeds. This grower left a “check strip” where the spray- Foliar Fungicide Applications on Damaged Crops? Soybean Aphids Weed Resistance Concerns & Cautions Photo: Jim Boersma, DuPont Pioneer Photo: Pioneer Customer Using Field360 Notes
  3. 3. er boom missed this spot in the field. In this field the Au- thority ® herbicide did a great job keeping heavy weed pressure at bay. Imagine if that entire field was overcome with waterhemp and or Lambsquarters. This is happening in Illinois, and states just south of us. Do not leave the blinders on and ignore these warnings. Weed resistance could be coming to a field near you! Parts of Minnesota and South Dakota saw extreme west- ern corn rootworm pressure in 2012. Extended corn after corn rotations had the biggest issues. Scout fields in the coming weeks as the 2013 CRW hatch has begun with young larvae now being observed. Hopefully the severe winter, along with the cold and wet spring have caused higher egg mortality. However, we won‟t know for sure until August. Dig up roots and immerse the whole root mass into a bucket of water. Swish the root ball in the bucket to dislodge the CRW larvae. A cup of Epsom salts in this solution makes the little larvae float to the top. Your local Pioneer sales rep or account manager can assist you with root digs. Control volunteer corn as this can attract CRW beetles. They mate and lay eggs in heavy volunteer corn growing in soybeans. Crop rotation is a good management tool that is effective against the western corn rootworm spe- cies. Remove any volunteer corn from soybean to pre- serve this rotation asset. DuPont™ Assure® II herbicide controls volunteer corn in soybeans. Avoid spraying glypho- sate past the R2 stage in soybeans. Many growers will spray a last shot of glyphosate when soybeans are well past the R2 stage. This can cause flowers and early developing pods to be aborted, which reduces yield. Herbicide timing is very important. Poorly planned herbicide appli- cations can negatively affect the plant‟s physio- logical processes. New sales area KS creates new positions and new assignments. Pioneer continues to go through a stage of rapid sales growth. There were some personnel changes that became effective June 1, 2013. Jim Boersma, previously a product agronomist, has been assigned back to his previous field agronomist posi- tion to cover the northern and eastern part of area KH. Clyde Tiffany remains a field agronomist and has ac- cepted a position in the newly formed KS sales area which encompasses central Minnesota and western Wis- consin. Dave Pfarr, formerly a field agronomist, has taken on a new role as NBU soybean services & stewardship man- ager. Neil Hansen accepted the field agronomist position, re- placing Dave Pfarr. He was previously an account man- ager in Jackson and Cottonwood Counties. Brad Weber remains an account manager, but his territo- ry in now managed by the KC sales area manager. Kevin Jones accepted the account manager position vacated by Chad Galles. Kevin will have sales responsi- bilities in Watonwan and Martin Counties. Mark Navara accepted an account manager position in the newly formed KS sales area in northeast Minnesota. As always, our team is here to provide you with world class agronomy information and service! Pioneer Field360 Notes pinpoints your field location via satellite imagery so you can record notes or photos on the spot.  Displays field boundaries for DuPont Pioneer custom- ers  Easy to use interface; compatible with Apple and An- droid Systems  Instantly map and organize data with notes and photos  Share your data from the field via email capability Pioneer® Field360™ Select software is an interactive, web-based subscription service that combines your field data with real-time agronomic and weather information  Track field by field Precipitation and GDUs using Field 360 Select  Scouting 101 with GPS located as-planted Products  On-The-Go organized field applied data  Satellite imagery pilot program in 2013 Contact your local Pioneer Professional for more Info! Evaluate Corn Rootworm Technology Updates to the DuPont Pioneer Team Photo: DuPont Pioneer