Month: February 2016

Wheat Stand Assessment Video

Wheat Stand Assessment Now is the time – Video

Now is the time to assess small grain stands, determine whether an early topdress is required and to assess the status of some early season pests.  This spring is unique in that in many fields the wheat crop has progressed to GS 4 and 5 in the fall and now growers need to also assessing powdery mildew at this time rather than more N to induce tillering as many fields are extremely progressed and additional N now might create more issues.  This article will detail some points to consider that may help with management decisions.
Spring tiller assessment is the first item to check in the field. Without having to do a miriad of calculations here is a simple method.  To do this you will need a 3 foot measuring stick.  Walk the field in numerous locations and drop the stick on the ground near the base of the plants and count the total number of tillers. Average the sites you check to arrive at an average tillers per three feet.   The goal is to have 70-100 tillers per square foot(25 plants per square foot).  To determine the amount your stand has once you count the total tillers found in the linear 3 foot stick calculate the tiller count per square foot by taking total tillers multiplied by 4 and then divided by the row width in inches. The new number represents tillers per square foot.  For example if you checked 5 areas in a field and the average tiller count you find is 60 tillers then you would take 60 times 4 (240) then divided by the row width(7inch) to arrive at a total of 35 tillers per square foot.  Since the goal is to have 70 -100 tillers and this is far below minimum,  Nitrogen will be needed to stimulate more tillering. 
A second way is to count the plants and use the table to provide guidance.  This guide converts sq foot to different linear feet by varying row spacings.
Row Spacing Table. 

Topdress  Decisions
In marginal fields wheat will respond to nitrogen applied at this time to promote tillering.  In no till 40-60lbs of actual N/acre will be adequate to promote tiller development.  Most of the wheat  grown in our area has a straw market available and with the removal of straw comes the removal of phosphorus and potassium.  Wheat removes 1lb of P205 and 1.8lbs of K20 per bushel of harvest.  That is a large amount of nutrient taken from the soil reserves.  I was in fields last year that double crop soybean crop planted after wheat showed potash defiency  due to low levels in the soil.  My point here is that unless the soil test is above optimum P and K removal  rates should be satisfied through fertilizer or manure sources.
Pest Considerations
This time of year most pests like insects and disease are not active. However, weeds may be of concern depending on the number of weeds and there growth relative to the wheat.   Weeds that encroach, may  hamper tiller formation and compete for nutrients.  As you scout the wheat stands and determine the need to apply a herbicide for control, be sure to check the plants crown location.   If roots are exposed from heaving or from improper planting depth, the herbicide may cause injury to the plants which will limit tiller development.  If this is the case then do not apply any herbicide unless absolutely necessary. 
Table 1.7-3. Small grain seed or plant densities expressed on a basis of square foot, plants per acre, or seeds per foot of row.
Seeds or plants per sq. ft Seeds or plants (millions/acre) Plants or seeds per foot
6 inches 7 inches 7.5 inches 8 inches 10 inches
24 1.05 12 14 15 16 20
26 1.13 13 15 16 17 22
28 1.22 14 16 18 19 23
30 1.31 15 18 19 20 25
32 1.39 16 19 20 21 27
34 1.48 17 20 21 23 28
36 1.57 18 21 23 24 30
38 1.66 19 22 24 25 32
40 1.74 20 23 25 27 33

Oat Seeding when is too early?

Here is a nice article discussing oat seeding from other states. This season we are off to late start but once this snow gets melted you might need to prioritize if Oats are on you rotation for spring.

Del Voight – Penn State Extension

University of Illinois at Urbana-Champain. aces.illinois.edu

Urbana-Champain, Illinois (April 16, 2009)–Wet soil and cold conditions to date have caused oat planting to lag behind normal, and consequently, questions have been asked about the impact of delayed planting on the yield of spring oats.

Iowa State University research on date of oat seeding in central Iowa found that after April 15, grain yield drops about 10 percent per week during April and 15 percent per week during the first two weeks of May. They suggest oat yields are best when seeded in late March to mid-April.
Research done by University of Wisconsin at Arlington found when oats where seeded April 18, 29, May 14, and 28, yields were 76.5, 70.6, 62.0, and 46.0 bushels per acre, respectively. Expressed as a percent of maximum yield, the above four dates yielded 100, 92, 81, and 60 percent, respectively.
University of Illinois recommends planting spring oats by April 15 in northern Illinois. A fungicide seed treatment is encouraged. They should not be planted later than May 1, unless being grown as a companion crop for forage establishment.
When drilling oats, a seeding rate of 2 to3 bushels (64 to 96 pounds) per acre or about 30 seeds per square foot is suggested. If broadcasting, the rate needs to be increased by one-half to one bushel per acre. If oats are being planted as a companion crop with alfalfa, seed only 1 to 1.5 bushels per acre.
Oat grain removes 0.38 pound of P2O5 per bushel and 0.20 pound of K2O per bushel. The recommended rate of nitrogen is dependent upon the soil organic matter and the presence of a legume. 50 to 70 pounds of nitrogen per acre are recommended for soil that is 2-3 percent organic matter and where no legume is seeded. If a legume is included with the oats, the nitrogen rate can be reduced by 10 pounds per acre.

Contact:
Jim Morrison
Extension Educator, Crop Systems
morrison@illinois.edu

Herbicides for Spring Weed Control in Alfalfa — Dwight Lingenfelter and Bill Curran, Penn State Weed Science

 It’s time to check the need for weed control. Keep in mind all of these herbicides are labeled for use in pure—stand alfalfa. However, only metribuzin and Pursuit can be applied to established alfalfa-grass mixes. Here are a few guidelines about available products:
Gramoxone Inteon 2L (paraquat) — May be applied at 2 to 3 pt/A to established “dormant” stands before 2 inches of spring regrowth. The weeds must be actively growing at the time of application. Gramoxone is also labeled at 1 to 2 pt/A for dormant application on new fall seeded stands. Gramoxone will desiccate any green tissue including actively growing alfalfa. Be especially cautious with new fall seedings. Gramoxone is effective on low to moderate infestations of winter annuals including chickweed, henbit, deadnettle, and mustard species. If winter annual weed infestations are severe, consider one of the soil active alternatives. Do not use on mixed stands.
Poast Plus 1E (sethoxydim) — Poast Plus controls annual grasses and suppresses perennial grasses in seedling and established alfalfa. Apply Poast Plus at 1.5 to 2.5 pt/A to actively growing grassy weeds. Poast Plus should be applied to small grasses and performance improves with warmer temperatures. Do not use on mixed stands.
Prowl H2O 3.8CS — has a supplemental label for use in seedling and established alfalfa. For seedling alfalfa (2-trifoliate to six inches tall), apply Prowl H2O at 1.1 to 2.1 pints pt/A prior to weed emergence. For established stands (i.e., alfalfa that was planted in fall or spring and has gone through a first cutting/mowing), apply 1.1 to 4.2 quarts/A prior to weed emergence. Applications can be made in the fall after the last cutting, during winter dormancy, or in the spring before alfalfa reaches 6 inches of regrowth and weeds have germinated. Prowl H2O will control many annual grasses and broadleaves including crabgrass, panicums, foxtails, lambsquarters, pigweed at the 1 to 4 pt rate. Other weeds such as annual bluegrass, common chickweed, dodder, henbit, prostrate knotweed, smartweed, and velvetleaf can be controlled with the 2 to 4 qt rate. Some stunting and yellowing to the alfalfa may occur after application. Do not harvest alfalfa less than 28 days after applying ≤2.1 quarts/A, or less than 50 days if >2.1 quarts/A. Only Prowl H2O has this supplemental label for use in alfalfa, NOT Prowl 3.3EC.
Pursuit 70DG (imazethapyr) — Pursuit may be used for weed control in seedling (2 trifoliates or larger) or established alfalfa. Apply Pursuit at 1.08 to 2.16 oz/A plus adjuvants to actively growing weeds 1 to 3 inches in height. Pursuit performance improves with warmer temperatures. If spraying during extended cold periods, expect weeds to respond slower or the herbicide can have reduced activity. Pursuit is effective on many winter annual broadleaves including small chickweed. Pursuit may be used on established alfalfa-grass mixtures.
Raptor 1AS (imazamox) — Raptor may be used for weed control in seedling or established alfalfa. Apply Raptor at 4 to 6 fl oz/A plus adjuvants to small, actively growing weeds and to established alfalfa in the fall or in the spring. Any application should be made before significant alfalfa growth or regrowth (3 inches) to allow Raptor to reach the target weeds. Like Pursuit, Raptor performance is influenced by temperature. Therefore, try to apply the herbicide on warmer days and when weeds are actively growing. Raptor has a similar spectrum of winter annual weed control as Pursuit. Do not use on mixed stands.
Select 2EC (clethodim) — Apply Select at 6 to 8 fl oz to actively growing grasses that are less than 6 inches tall. Rates up to 16 fl oz may be used to control larger grasses, annual bluegrass or perennials such as quackgrass. Include a crop oil concentrate in the spray mixture. May be tank-mixed with Pursuit, Buctril, or 2,4-DB for broadleaf weed control. Do not use on mixed stands.
Sinbar 80W (terbacil) — May be applied to established alfalfa at up to 1.5 lb/A or to a new fall seeding at 0.33 to 0.5 lb/A. The reduced rate seedling year application is specifically aimed at chickweed. Sinbar is effective on a number of annual broadleaves and some grasses at the higher rates. Apply to ‘dormant’ alfalfa before 2 inches of spring regrowth. Do not use on mixed stands.
Metribuzin 75DF (formerly Sencor) — May be used on established alfalfa. Apply 0.5 to 1 lb/A before spring regrowth. Impregnation on dry fertilizer can improve crop safety and allow for slightly later applications (up to 3 inches spring regrowth). Sencor controls winter annual broadleaves and grasses (higher rates for grass control). May be used on mixed alfalfa-grass stands. Higher rates can potentially cause a reduction in grass stand.
Velpar 2L (hexazinone) — Apply Velpar to established alfalfa at 2 to 6 pt/A during the dormant period before 2 inches of spring regrowth. Velpar is effective on annual broadleaves and grasses. Velpar is the most effective dormant season treatment for suppression of dandelion and dock species (higher rates for grasses and perennial suppression). Do not use on mixed stands.
Your best bet when controlling…

  • Chickweed — Gramoxone Inteon, Pursuit, Raptor, Metribuzin, Velpar
  • Annual bluegrass — Gramoxone Inteon
  • Henbit/deadnettle — Gramoxone Inteon, Metribuzin, Velpar
  • Yellow rocket — Pursuit, Raptor, Metribuzin, Velpar
  • Dandelion — Velpar (suppression) or Pursuit (early spring is better)
  • Curly dock (suppression) — Pursuit or Raptor (early spring is better)

Consider Air Temperature and Other Environmental Conditions When Making Burndown Applications — Bill Curran, Penn State Weed Science

With the dry spring weather we are experiencing, some farmers and applicators are considering entering fields and spraying perhaps earlier than normal. Remember that the activity of all foliar applied herbicides is dependent on air temperature as well as other variables. If you are trying to kill a cover crop or even winter annual weeds, susceptibility of the target species and environmental conditions (temperature, moisture, sunlight, etc.) play a role in the effectiveness of the treatment.
The University of Illinois conducted a field study back in 2002 that compared glyphosate, paraquat (Gramoxone), and paraquat plus metribuzin (Sencor) for their performance under challenging spring conditions. The herbicides were applied at six different timings in the spring based on daytime high air temperatures ranging from 47 F to 87 F. Common chickweed and henbit were present in the study. Overall, temperature had no effect on chickweed control with glyphosate or with paraquat plus metribuzin and both provided 90% control or better regardless of air temperature. However, control increased from about 70% at 47 F to about 90% at 75 F with the paraquat alone treatment. In contrast, henbit control was less than 80% with all herbicides until applications were made when daytime high air temperatures were above 75 F. In fact, control with glyphosate and paraquat was less than 50% at temperatures up to 75 F. The paraquat plus metribuzin treatment was somewhat better providing close to 80% control at 75 F. This study is a nice example of how not only temperature plays a role in foliar herbicide activity, but also target species and how a soil residual herbicide like metribuzin (or atrazine) can increase effectiveness, especially with a product like paraquat. Temperature had little influence on common chickweed control with glyphosate; however, application temperature significantly affected glyphosate activity on henbit. Also consider herbicide rates, overcast conditions at application, adding AMS and other appropriate adjuvants to the spray tank, tip selection and gallonage for better spray coverage, etc. when making spring applications under less than ideal conditions.