21 April 2014

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 regarding Pesticides and water.  Pesticides and Water .   Here is a breif over view of key points Reeves Petrof details in his factsheet.
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.  
Soft is below 50ppm
Medium Hard is 50-100ppm
Hard is from 100-200ppm
Hardness is the make up  of the minderals in the water and may contain either Ca++, Mg+++or Fe+++

Pesticide Affects?
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.

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 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 t
sulfate 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. 
2.  Organic Acids.  A very effective treatment is utilzing  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+.
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.

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 sulfonyl urea 
• 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 a Factsheet that UAP has out 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.

Assessing Alfalfa Stands

Dr. Dan Undersanders how to assess alfalfa stands now.

How to assess spring Stands of Alfalfa

Key Numbers to assess right now.
Factsheet to bring to the field during assessment.

Marvin Hall, Forage Specialist

Unfortunately, “taking out” or saving and alfalfa stand is not always an easy decision. But with the current price of corn I think that decision will be on the minds of many Pennsylvania farmers. Recent research can help in assessing the productivity and profitability of a questionable alfalfa stand.
The magic number of plants, that traditionally indicated when it was time to rotate out of alfalfa, has been 4–5 plants per square foot. However, depending on fertility and weed invasion, alfalfa stands with 5 plants per square foot can yield as much as a stand with 10 or 15 plants per square foot. The correlation between plants per square foot and yield is very low since individual alfalfa plants respond to decreasing stand density by producing more stems. An increase in stems per plant compensates for fewer plants and maintains the yield.
A better indicator, than the number of plants, of the productivity of an alfalfa stand is the number of stems per square foot. Fields with 55 or more stem per square foot produce maximum yields. As the stem number declines below 55 per square foot yields begin to decline. Once stem numbers falls below 40 per square foot alfalfa fields begin to loose profitability and should be rotated out of alfalfa.

10 April 2014

manure track affect on rye.Video: 2014/04/09

3000 gal per acr appication impct o wheel traffick on rye.  Field was not frozen when applied. It appears the tires layed the rye over and then the coating sealed over the tracks and smothered the rye.

08 April 2014

Plant Tissue Testing Winter Wheat to determine fertility needs this spring

Del Voight- Penn State Extension

Several growers are considering more high yield management for the wheat crop. A few growers last season enjoyed 100 bu/acre plus while managing for high yield wheat crops.  The first step is to gain an accurate soil test. The second step is to collect a sample in the spring for plant analysis. The Ag Analytical Lab provides the testing for the results.  Here are the specifics to gather the samples.
Once the plant fully greens up when the weather breaks gather the samples and send them off. This will allow for adequate time to determine a nutrient strategy before peak growth at GS5 Wheat Growth Stage Diagram.

Small grains
Seedling stage (less than 12”...All the above ground 50-100 plants)

Prior to heading The 4 uppermost leaves. 40-50
Sampling after heading not recommended
Once you get the results refer to this site for more specific information on the what is acceptable levels in the plant.
Key nutrient numbers for wheat

Cereal Rust Mite, Abacarus hystrix(Nalepa): A pest on Timothy

The presence of this mite as a significant factor of timothy losses has been reported in Lancaster, Lebanon, Dauphin and York counties over the past 2 years.  Some yield loss estimates range from 30-70% loss of yield.  This problem, however, has most likely been present for a longer period of time but gone unnoticed.  In Maryland, problems have been seen for the last 10 years. When the problem first occurred in during the early 1990's in Maryland, the mites only infested the variety Climax, but high populations of the mite have recently been encountered on other varieties.  In 1999, the mite was officially identified as the cereal rust mite, A.  hystrix, by Dr. Ronald Ochoah, a USDA-ARS mite specialist.  This is the first record of this species in Pennsylvania.  A.  hystrix has been infesting timothy for some time, but due to its small size, growers have attributed its subtle injury symptoms to agronomic reasons.  Based on grower contacts and surveys by extension personnel in Maryland, Delaware, and Pennsylvania, the range of cereal rust mite infestations is expanding and virtually every acre of timothy grown in central and western Maryland and southeastern Pennsylvania is infested to some degree.
             Timothy hay is a very profitable cash crop produced on an estimated170,000 acres in Pennsylvania.  It is usually marketed to the horse industry at premium prices ranging from $75 to $180 per ton. Gross revenues for this crop range from $216 to $315 per acre.  The prices of good quality timothy hay can exceed that of alfalfa.  Production of timothy in Pennsylvania is currently not high enough to satisfy the horse industry; so considerable quantities of timothy are imported into the state to meet the demand.  Thus, reductions in the yield and quality of timothy grown in Pennsylvania result directly in economic losses  to growers and indirectly to horse owners who have to pay higher prices for imported hay.

Adult rust mites are very small (<1mm). They are spindle-shaped, with four legs and may be white, yellow or orange. You will need a hand lens to
see them. To check for eriophyid mites, look for off-color foliage, leaf or bud abnormalities. Use a 10X or 20X hand lens. Large mite populations often produce many elongate, white shed skins. The mites feed on bulliform cells at the base of grooves on the adaxial leaf surface.  Eggs are deposited in the grooves, and both eggs and immatures become distributed higher in the canopy as leaves unfold.  Adult mites move downward in the plant crown, where they prefer to feed on the youngest tissues of the plant.  The mite undergoes numerous generations per year (a generation time of 16-18 days at 20o C) and there is no known diapause stage.  Although development is reduced, mite stages are active during the winter in the crowns of its host plants.
            The feeding of A. hystrix causes direct injury to timothy, which results in retarded growth, stunting, and discoloration.  No other pest species or agronomic factor is more important as a constraint in timothy production than the cereal rust mite.  The feeding of A. hystrix causes direct injury to timothy, which results in retarded growth, stunting, and discoloration. Severe mite infestations have two negative impacts on local growers.  Feeding injury causes substantial yield losses, as much as 50%, and also reduces hay quality by the brown discoloration.  Horse producers are reluctant to buy hay that is not the normal color of quality timothy.  As a side note, A. hystrix is also known to vector ryegrass mosaic virus (RMV), a serious disease of temperate grasslands, and may be a vector of agronpyron mosaic virus (AMV), a minor disease of wheat and other grasses.  These diseases cause substantial losses to pasture production in other parts of the world, especially in Europe.  However, the presence of RMV and AMV in the USA has not been detected.  The symptoms of feeding injury on timothy resemble the typical symptoms of a viral infection; however, disease infections have never been confirmed by ELISA determinations.  Nonetheless, if these foriegn viruses enter the US, there exists the potential for their virulence on forage grasses and wheat due to the abundance and wide distribution of the mite vector.  
Time of Attack:
            Adults and eggs are present overwinter and the adult hatch begins in March with the peak adult population peaking in April.  Damage is most evident in April and will continue into May.
            Growers should observe fields in early to mid March and look for the presence of small round eggs in the grooves of the timothy leaf surface. 
Economic Threshold:Lebanon Timothy mite Experiment(Field research and Demonstration)

Treatment is recommended in fields with a previous history of cereal rust mites and/or when 25% of the plant tillers exhibit curled tips of the new leaf blades within several weeks following green-up.  There are no know thresholds developed to date.  Research is underway to develop a monitoring plan and threshold levels for economic justification of treatment.  The following tables provide some economic analysis of the pest.
Video for Scouting.
Scouting Rust mites on Timothy

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 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

25 March 2014

Manure Application Consideration

Del Voight- Penn State Extensiojn

Manure is a fertilizer and even application is essential to ensuring even crop emergence and even mineralization as the season progresses. A typical manure  analysis varies greatly however it is not uncommon to  have P and K values in that are quite high range so  if you soil test into the heavy strips as illustrated an inaccurate test and management inputs could be severely off.  Here is a video  illustrating how dramatic the manure application can be in one case study.
ARDrone Manure video