Lebanon Crop Management Video

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22 February 2016

pH and Water modifications to improve pesticide performance.

Del Voight- Penn State Extension
I read with interest an article from an Pesticide Education Specialist  Reeves Petrof from Montana State University regarding Pesticides and water.   Here is a brief over view of key points Reeves Petrof details in his factsheet.  I have also added items for the Penn State Vegetable guide as well as the Penn State Water Resources Team.  Pesticides are chemicals and when introduced into water may react depending on the hardness of the water. Cations(+)  and anions(-)are similar ot magnets.  Hard water typically has a positive charge so if a pesticide is an anion or negative charge they will bind together and will not seperate once applied to the pest in question. This reduces the effectiveness of the product.  A simple water test of your primary spray water supply now will determine how you manage the water this season. Most farms water sample for either dairy, swine and poultry so a water test should be relatively simple to locate and or gain. Here is a simple table to the hardness of water.  
Hardness is the make up  of the minerals in the water and may contain either Ca++, Mg+++or Fe+++
Soft is below 50ppm
Medium Hard is 50-100ppm
Hard is from 100-200ppm
Pesticide Affects?
I have had several herbicide and insecticide failures that I could not diagnose for certain but I had suspected issues with the water. All of the cases that  I was involved in happened to be in spray tanks that were filled but not were idle overnight before being emptied and I had theorized a reaction with the water rendered the pesticide useless. One take home message is to avoid allowing cerrtain pesticides to remain in the tank for any long term timeframe.  One example  I was involved with  included Dimethoate which can react in literally minutes after mixing pending the water pH.   Salt-formulated  herbicides such as Roundup (glyphosate), Poast  (sethoxydim), Pursuit ( imazethapyr), and Liberty (glufosinate) are subject to being bound in the water and for this reason many labels instruct to lower the pH of the water to ensure optimum performance.  These minerals may bind with salts of certain  herbicides and with some surfactants to form an insoluble salt. These insoluble salts then “fall out” out of solution decreasing herbicide or surfactant  efficiency. In the case of isopropylamine salt  formulations of glyphosate, the positively charged cations of calcium (Ca2+) and magnesium (Mg2+) salts compete with the isopropylamine in the formulation for association with the glyphosate anion (negatively charged). This results in the herbicide having a greater difficulty absorbing into the plant leaf. 
 In addition, research has shown that extremely hard  water, 600 ppm (35 grains/US gallon), can almost  completely antagonize 2,4-D amine applied at a low  rate of about 4 to 8 ounces per acre. Hard Water also affects fungicides and insecticides so it is important to read the labels of all products to determine ideal pH ranges. Here is a small list of some common products in addition to the glyphosate formulations which is more widely recognized.
      Common  Name Trade Name Half-life* at Different pH Values**
Fungicide Example
      Propiconazole       Tilt           Most effective in pH 5 to 9; use within 12 to 16 hours.
      captan              Orthocide        pH5 = 32 hours,      pH7 = 8 hours,      pH8 = 10 minutes
Insecticide Examples
      carbaryl            Sevin               pH7 = 24 days,       pH8 = 2.5 days,     pH9 = 1 day
     dimethoate        Cygon,            pH4 = 20 hours,      pH6 = 12 hours,     pH9 = 48 minutes
     Permethrin       Pounce             Optimum stability pH 4
Herbicide Examples
     paraquat    Gramoxone Extra not stable in pH above 7
Plant Growth Regulators
     Gibberellic Acid   Promalin       A buffered wetting , final spray should not  exceed pH 8

READ THE LABEL!
So how do you reduce the hardness of the water?

Note: Acidifiers should not be used in conjunction with some organo-silicone adjuvants as increased 
acidity may enhance chemical breakdown of the adjuvant. In addition, sulfonyl urea herbicides (Accent, Harmony etc) can degrade in acidic environments below 7. READ THE LABEL!
 The most widely used materials to help with hard water is AMS.
1.  Ammonium Sulfate (NH4SO4). Ammonium sulfate (AMS) has been used successfully to increase herbicide efficacy on a broad spectrum of weed species. This is particularly true for the weak-acid herbicides like Roundup (glyphosate), 2-4--D, Pursuit (imazethapyr),, Poast (sethoxydim) and Basagran (bentazon).. The AMS adjusts the pH so that more of the active herbicide is transported across the leaf surface and into the plant.. An added benefit is that tsulfate ions (SO4) bind up with hard water minerals. In addition, ammonium-herbicide combinations are more easily absorbed by some weed species. A general rule-of-thumb for adding AMS is the addition of 2% AMS by weight or 17 lb of dry AMS per 100 gallons of water for most applications. AMS should be added to the spray carrier solution prior to the herbicide and always, consult the pesticide label for mixing instructions. There may be limitations on the use of fertilizer-based surfactants. The industry has strived to make this process simpler for the applicator by liquifying AMS and there are numerous products that are liquid AMS(Turbo and numerous others) and each product needs to be added at the appropriate rate according to the label to effectively bind the hard water. They can range from a per acre to a per 100 gallon dilution. There are some new products in this arena that either are AMS and or UAN derrivitives. .  Halo is relatively new the area and has been used to replace AMS, Turbo, Request, Choice, and other similar products. 
2.  Organic Acids.  A very effective treatment is utilizing citric acid..  The addition of an organic acid such as food grade citric acid will effectively remove hard water ions from solution. Organic acids are effective because the conjugate base (negative portion) of the acid binds to and removes positively charged cations from solution. A weak acid, such as citric acid, will provide a stronger conjugate base, and therefore, will be more effective than a strong acid such as nitric or hydrochloric acid. The addition of the organic acid will also lower the spray solution pH because of the addition of hydrogen (H+) ions. Organic acid is added to the water carrier prior to the addition of the herbicide. A use rate of 2.2 lbs of citric acid per 100 gallons of water should be adequate for water with 250 ppm of Ca2+. From my travels many poultry growers have citric acid on hand for use in the poultry watering system.
3.  Some sources of Urea Ammonium Nitrate(UAN) may also reduce the hardness but not as effective as AMS and this is why AMS is preferred over UAN.  Some UAN utilizes a Sulfuric Acid source to add Sulfur to the fertilizer mixture and may enhance the acidification from UAN.  

Use the following general guidelines once you have determined the pH is of your spray water. Remember, READ THE PESTICIDE LABEL. 
 • pH 3.5-6.0 Satisfactory for most spraying 
and short-term (12 to 24 hours) storage of 
most pesticide mixtures in the spray tank. 
Read the label. Not suitable for sulfonylurea (Accent, Harmony)
herbicides 
• pH 6.1-7.0 Adequate for immediate spraying 
of most pesticides. Do not leave the spray 
mixture in the tank for over 1 to 2 hours to 
prevent loss of effectiveness. 
• pH 7.0 and higher. Add buffer or acidifier. 
You can offset the effects of water pH by adding certain adjuvants (additives) that can either change the pH or your spray mixture or maintain (buffer) the levels of dissolved solids and organic particulate matter….dirt! These soil particles decrease Roundup (glyphosate) and paraquat activity and can cause equipment wear. This type of antagonism cannot be corrected by adding AMS or an organic acid. Always choose a water source that is free of dirt, grit, and organic matter. 
Adjuvants and Surfactants. 
Water softening additives designed for pesticide applications are available to offset hard water problems. While nonionic surfactants will generally enhance herbicide activity on most weed species, they will not 
overcome the antagonism between salt-based herbicides and hard water. Therefore, under hard 
water conditions, AMS or organic acids should be used in conjunction with nonionic surfactants to 
maximize herbicide absorption. Read the label of surfactants that you buy. Some AMS surfactants 
already have a nonionic surfactant added pH if it already at the desirable level. Here is an older however useful  Factsheet that UAP has produced with Loveland regarding its LI700 product that is a penetrant as well as a hard water solution .LI 700 UAP this product is designed to aid in penetration as well as reduce pH. I am not promoting their product rather the fact that they have a large list of pesticides and their pH requirements. There are numerous other products similar to this product so check with your supplier for these products and use.
Final Thoughts

  1. The key is to read the label
  2. Gain a water test
  3. Fill the tank half to 2/3rd full and add the water treatment BEFORE adding any of the products that are affected by the pH or Hardness.
  4. Add other products in the right order to ensure mixing.
By following some simple rules the maximum effectiveness of herbicides, insecticides, fungicides and plant growth regulators may be achieved and avoid failures in the field.

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. ftSeeds or plants (millions/acre)Plants or seeds per foot
6 inches7 inches7.5 inches8 inches10 inches
241.051214151620
261.131315161722
281.221416181923
301.311518192025
321.391619202127
341.481720212328
361.571821232430
381.661922242532
401.742023252733

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

17 February 2016

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.