Soybean Cyst Nematode (SCN): A Silent Yield Robber

July 2, 2015
Author David Hingst

Effectiveness of SCN Resistant Varieties

Root digging during July to mid-August is an effective time to evaluate roots for SCN.  At this point you can evaluate the genetic resistance being provided by SCN resistant varieties.  Evaluate roots for the small white dots you note in the picture above.  These represent the adult SCN females.  If the female SCN are present on your resistant varieties, several things could be happening:

  1. Genetic resistance is primarily provided from breeding lines that contain PI88788 or Peking.  Some SCN populations have shown increased reproduction on the PI88788 source of resistance. 
  2. SCN populations in general may have increased in your fields and you are now facing additional SCN pressure.

It is never fun digging roots and looking for little white specs, but understanding the SCN pressure now will help explain yield performance this fall.  Additionally, identifying the SCN pressure now will dictate your potential need to follow up with fall soil sampling for SCN.  Understanding your SCN pressure will influence your decision for crop rotation in 2016 and your decisions regarding 2017 soybean variety selection as well as the potential need of nematicide seed treatment.


Attached is a source for more information about SCN resistance evaluation.
1.  How’s Your SCN Resistance Holding Up? (6/22/2015)
http://www.extension.iastate.edu/CropNews/2015/0622Tylka.htm

If you have any questions regarding SCN pressure, contact your Hoegemeyer DSM or Agronomist.


 


Categories: Management, Pest, Soybeans     Comments: 0     Tags: David Hingst, SCN, Soybean Cyst Nematode, Soybeans    

Western Corn Belt – Mixed Bag Spring 2014

June 10, 2014
Author Ryan Spurgeon

INCLUDED BELOW ARE SEVERAL AGRONOMIC TOPICS AND ISSUES RELATED TO THE 2014 GROWING SEASON. LET’S ROLL…..

Hail Damage – By this time most fields are currently being or already have been evaluated for stand loss and potential replant due to the major widespread hail event which occurred on the evening of June 3rd 2014. For those corn acres that are being replanted, we have already been forced to back up in maturity by about 5-7 days RM due to calendar date. Next week, that number likely needs to back up by roughly another 5 days RM unless silage is an option. As we approach June 20th, planting corn is likely not a good idea for the geographies affected by the storm this year. Keep in mind, not all early hybrids move south as well as others, so extreme reductions in maturity (sub 100 day) are usually not good options. Soybeans are highly affected by length of daylight (more so than corn) in terms of when they are triggered to flower and begin their reproductive stages. In other words, a 2.9 maturity soybean planted on June 10th will not take as many days to mature as one planted on May 10th.  It is best to stick close to your adapted normal maturity for the near term.

Fungicides and Hail Damaged Corn – This has become a controversial topic in the last few years. We will not go into great detail here but below is a link to a somewhat recent article published by the University of Nebraska. In a nutshell, I believe each field is unique and the fields with the most reliable remaining yield potential are the ones that stand to benefit from just about any input, not just fungicides. I personally am not ready to promote blanket treatments of foliar fungicide to all V5-V7 corn that was damaged by hail. The science tells us that most fungicides have about an 18 day window in terms of residual protection. They are not effective at stopping infection of systemic infections such as Goss’s Wilt and stalk rot pathogens. If this had been a later occurring hail event when corn was at the late vegetative stages and/or early reproductive stages, I think the argument becomes more valid since those leaves/tissues higher in the canopy do indeed contribute to the plant’s photosynthetic yield factory. 

CropWatch Article

Twisted/Tied Up Corn Plant Whorls – It seems almost every year now we receive several reports of corn plants with twisted or tied up whorls. This year is no different. This is often referred to as RGS or “Rapid Growth Syndrome”. Opinions vary as to why this happens. Some blame it entirely on the environment while some think there is sometimes a link to herbicide. I would side with those that claim it is nothing more than a genetic X environment interaction we see when corn plants hit a rapid stage of growth, sometimes soon after a relatively cool period followed by favorable growing conditions. It is seen in many hybrids and across many brands. The good news is that past track records would suggest these plants will unravel and be fine with little to zero affect on yield. Just don’t be alarmed when you see random light yellow colored plants in the field once they unravel. Once they are able to intercept sunlight and resume photosynthesis, they should green up relatively quickly.

Rootworm Hatch – It has begun in most of the Hoegemeyer footprint. Typically about 50% of egg hatch occurs between 684-767 accumulated growing degree days (GDD). We are starting to approach that GDD level in some areas along and south of the I-80 corridor. Larvae will continue to hatch for the next few weeks seeking out corn roots to feed on before eventually pupating and then emerging as adult beetles later this summer. High risk fields would be those with known prior pressure, fields with continual use of the same single mode action corn rootworm trait, and multi-year continuous corn acres in general. The best way to evaluate fields is to dig roots and evaluate for injury. A bucket of water is often beneficial in order to clean off roots, which makes finding small larvae and feeding scars more visually evident.

Soybean PPO Herbicide Carryover – There have been some instances of possible PPO soybean herbicide carryover which has injured corn plants this year. This has been mainly more to the East and South (Southeast NE, Northwest MO, and Iowa) where these herbicides (PPO/Cell Membrane Disruptors) are heavily used to combat heavy waterhemp pressure. In most instances, this was associated with a relatively late planting of soybeans last year in conjunction with a high rate of a residual PPO soybean pre-emerge herbicide or where a late post application (July) of  specific PPO herbicide(s) was applied to soybeans. In either case, the relatively dry autumn, winter, and early spring is largely to blame as a lack of soil moisture did not enable the chemical to degrade as quickly as compared to normal. Several of these herbicides have a 10 month crop rotation restriction for going back to corn the following year, which means we may have been right up against that time period for those late planted and/or late sprayed fields when chased with a somewhat early (late April) corn planting date. Most plants are recovering with minimal stand loss with the exception of some hot spots in fields where some stand loss is evident.

Until next time, Contact your local Hoegemeyer DSM or Agronomist with questions. Hopefully we will begin to fall into a more stable weather pattern in the coming days/weeks. No more frost, hail, flooding, or wind is needed Mother Nature!!!


Categories: Corn, Disease, Fertility, Management, Pest, Planting, Ryan Spurgeon, Soybeans     Comments: 0     Tags: Fungicide and Hail Damaged Corn, Hail Damage, Hoegemeyer, Rapid Growth Syndrome, Rootworm Hatch, Ryan Spurgeon, Soybean PPO Herbicide Carryover    

Western Corn Rootworm: Man vs. Insect

September 26, 2013
Author Ryan Spurgeon

Of the two species of corn rootworm which typically infest the Corn Belt, the Western Corn Rootworm (WCR) has become increasingly troublesome in the last few years. Populations within fields have increased rapidly, their geographical range has appeared to have widened somewhat, and transgenic rootworm traits are no longer reliable as total stand alone treatments under heavy pressure. True genetic resistance by the Western Corn Rootworm has been confirmed in one transgenic rootworm trait with strong likelihood of it in another as well. Why? Good question with several likely answers. For one, the WCR is a very genetically diverse species which increases the likelihood of it developing resistance when continually exposed to the same treatment with a single mode of action (not unlike waterhemp and glyphosate resistance). For several years, many corn fields have used transgenic corn rootworm traits as their sole defense against corn rootworm. Continuous corn acres have also increased. The WCR life cycle typically includes a prolonged period of time when larvae are attacking corn roots. As populations increase and larvae become larger it becomes more likely that some larvae will escape a lethal dose of protein.

Rootworm will always win if we try to control them with a single approach. They have proven this time and time again. One will need to consider multiple tactics going forward. These include stacking and rotating/stacking corn rootworm traits with different modes of action, use of soil applied insecticides in conjunction with corn rootworm traited hybrids, selection of hybrids with above average root scores, managing adult beetle populations with foliar insecticide, and last but certainly not least, ROTATION. At some point rotating out of corn for at least one year still gives us the best chance to significantly lower corn rootworm survival for the following year.

Generally, it seems once you move north of U.S. Highway 30, WCR problem fields become much more common. Northeast Nebraska, North Central Iowa, and over into extreme Southeast South Dakota have become particularly troublesome within the last 2 years. To date, there is no confirmed corn rootworm resistance to the Herculex® rootworm trait. Being a binary event with two proteins, insecticidal protein expression is generally stronger than other corn rootworm transgenic events currently on the market. That being said, I do not feel it is wise to repeatedly use it as a stand alone treatment under high rootworm pressure environments neither, for all of the same reasons mentioned prior. In theory, each field should be considered separately which makes it difficult to come up with a corn rootworm trait/hybrid standard across all acres.

Currently Hoegemeyer’s triple stack corn line-up primarily consists of Optimum® AcreMax® Xtra, Herculex® XTRA, and Optimum® AcreMax® Xtreme traited hybrids which deliver the Herculex® corn rootworm gene as their base for transgenic rootworm control. Agrisure® 3000GT and Optimum® TRIsect® hybrids utilize a different corn rootworm event with single gene protein expression.  We do not recommend using this as a stand alone treatment under any continuous corn acres unless one is confident there were very low adult beetle numbers present in  the field during the summer and prior to harvest, no evidence of root feeding and/or lodging, and the field(s) are well outside the geography we deem as most problematic (which is generally, but by no means exact, as one approaches and moves north of U.S. Highway 30).

As you enter fields for harvest this fall and begin to look ahead to next year, contact your Hoegemeyer DSM or Agronomist with questions on corn rootworm management.


Categories: Corn, Pest, Ryan Spurgeon     Comments: 0     Tags: Continuous Corn, Herculex, Ryan Spurgeon, Western Corn Rootworm    

Watch for Adult Rootworm Beetles!

July 17, 2013
Author Don Moeller

In many corn fields, tassels are emerging, silks are forming and the pollination process is happening.  This is also the time when rootworm larvae are emerging as adult beetles.  Take a little time out of your busy schedule to check for adult rootworm beetle pressure on the fragile emerging silks and developing ears (see adult beetle picture 1).

Just because a field has been planted to a triple stack corn does not guarantee that adult rootworm beetle pressure will not be there.  Maybe the field next door has the emerging beetles that will migrate into yours and start feeding on silks in your field like you see in picture 2.  Another possibility is that there is a volunteer corn problem or weeds that have acted as hosts for the rootworm as they develop into adults.

Chances are pretty good that if your field ends up having ears with no silks on them (as you see in picture 3) there most likely will be a yield loss.  Staying on top of this potential problem could benefit you with a lot of extra bushels this fall.  

If you have questions, contact your Hoegemeyer DSM or Agronomist.


Categories: Corn, Don "Moe" Moeller, Management, Pest     Comments: 0     Tags: Adult Rootworm Beetles, Corn, Don "Moe" Moeller, Pest Management, Rootworm    

Japanese Beetles are Invading

June 29, 2012
Author Andy Kwapnioski

The Japanese beetles are invading corn and soybean fields in the Midwest.  Mild winters and earlier-than-normal planting conditions (first 2 weeks of April) will create a suitable environment for emerging beetles to wreak havoc on pollinating corn fields.  I have noticed increasing pressure from these beetles in the eastern part of Kansas.  Some farmers have sprayed for these insects in pollinating corn fields and in parts of Missouri high numbers of Japanese beetles have been noticed in corn and soybean fields.  Japanese beetles can injure corn fields during multiple stages in the insect’s lifecycle.   In the spring, overwintering grubs can feed on root hairs decreasing a plants ability to find nutrients and moisture and the adult beetle can defoliate the corn plant to levels warranting treatment.  Economic damage most commonly occurs to corn fields because the beetles will congregate on the ears and feed on the emerging silks which can significantly reduce pollination and yields.  Typically where you find one on an ear, you will find many because they release a pheromone which attracts other beetles to that feeding site.  It is important when scouting to look beyond field edges which typically will have higher numbers of feeding Japanese beetles, and look throughout the field as feeding could be much less.  Economic thresholds can be met when silks are clipped to less than ½” before 50% of the field is pollinated, and/or 3 or more Japanese beetles per ear.  Defoliation estimates need to be made when determining economic thresholds for soybeans.  Typically Japanese beetle feeding alone does not warrant treatment but multiple pest feeding together will. Defoliation is much more of a problem when soybeans are flowering and pod fill is taking place - 20% defoliation at this time call for chemical treatment. 

  • Be prepared for grasshoppers, scout grassy field margins and if 20 to 30 grasshopper nymphs are found per square yard than treatment is warranted (10 to 15 in the field)
  • The recent blessing of rains efforts need to be made in scouting fields for Grey Leaf Spot (GLS) especially on low lying fields along creek and river bottoms, and where irrigation is present.  Conditions are right in river valleys, north central Kansas, and around the Dodge City area.
  • If you missed an opportunity to double crop, or if you had a crop failure consider trying a cover crop mix to improve soil health, add N, reduce weed pressure, and/or to conserve moisture for next years crops.

If you have any questions, contact your local Hoegemeyer District Sales Manager or Agronomist.


Categories: Corn, Management, Pest, Soybeans     Comments: 0     Tags: Andy Kwapnioski, Corn, Japanese Beetle, Management, Pest, Pest Management, Soybeans    

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