April 26, 2007
In this issue
§ Sandhill crane repellent (Avitec) available in 2007
§ Soil-applied residual herbicide benefits in soybeans
§ Soybean seeding rates
§ New crop and pest management soybean hotline
§ Soybean rust and freezing temperatures in the south
§ Soybean rust fungicide update for early 2007
§
Increased
§ Management of foliar wheat diseases, Part 2
§ Fungicide efficacy for control of wheat diseases
§ Fertilizer placement
§ How much winter injury did alfalfa receive from recent low temperatures?
§ Regional reports
§ Weather news
The crane repellent Avitec is available again this summer
for corn in
Crane populations and crop damage have risen over the last
several decades. Harassment methods are time consuming and often do not work,
and simply drive birds to neighboring fields. Recognizing the problem, the
International Crane Foundation in
For agricultural use, anthraquinone is manufactured and sold by Arkion Life Sciences as Avitec. It can be applied as a liquid seed treatment by a commercial seed-treater, or by the do-it-your-selfer in the dry form as a planter box treatment. It is NOT a restricted use pesticide, and you don’t need a DNR permit to apply it. However, you must have a copy of the Section 18 label at the time of application. Avitec repels cranes without harming them. The birds detect the treated seed and avoid feeding on the corn. However, cranes may still be present in treated fields, feeding on other seeds, worms or insects.
In 2006, most of the Avitec used was in the powder form as a
planter box treatment. The state with the highest number of acres treated last
year was
Note that the product label for the dry formulation of Avitec indicates that the powder must be mixed thoroughly into the planter box. Also, graphite and talc should NOT be added when using the dry Avitec formulation. If you have time to get seed treated with the liquid product, that should solve some of these problems and improve consistency. However, used properly, the dry formulation appears to work well.
The target cost for Avitec is about $5 per acre. That price may vary a bit depending on the local distributor. If you have trouble finding Avitec in your area, or are quoted a price considerably above $5, Arkion urges you to call them directly or visit their web site (contact information at the end of this article). They can help you find a dealer and a reasonable price.
Cranes are amazing birds. They are considered the oldest
living bird species, as close as we can get to dinosaurs. But they can also be
destructive to crops. Sandhill cranes return to
Sandhill cranes have
a varied diet, eating plant tubers, seeds, insects, worms, mice, frogs, and snakes.
Some of their feeding – on cutworms, grubs, and other soil pests – is beneficial
to crop production. However, a crane can probe down into the ground with its
long beak and pluck out germinating seed and seedlings as it walks down a row.
A group of cranes can destroy acres of corn in a short period. The majority of
crop damage from cranes is reported from southwestern
Some growers have proposed feeding or baiting cranes by putting seed corn along field edges to lure them away from production fields. Every bird expert I talked to said NO to this idea. Cranes prefer the open middle of fields where they can see potential predators, so they probably wouldn’t stay on bait corn on a field edge. Also, in addition to grain, they eat high-protein food like insects, and thus naturally may wander from the baited area. Finally, baiting might make things worse by drawing additional birds to a field.
Harassment and removal (a nice way to say shooting) of birds
is an option, but it is time consuming. A permit is required to kill cranes. To
get information on obtaining a permit, call the USDA-APHIS Michigan Wildlife
Service office in
Avitec pricing, availability
Arkion Life Sciences LLC
Research on crane repellents, crane biology
International Crane Foundation (ICF)
Baraboo, WI 1-608-356-9462
http://www.savingcranes.org/conservation/our_projects/detail.cfm?did=4&cid=1&aid=43&pid=17
Section 18 labels for Avitec
Michigan Department of Agriculture
http://www.michigan.gov/mda/0,1607,7-125-1569_16988_35290-127656--,00.html
Permits for crane removal
2803 Jolly Road,
517-336-1928
The use of postemergence
(POST) glyphosate in Roundup Ready soybeans has been the primary weed control
program used by many
One way to help overcome
some of these concerns is to implement the use of a soil-applied or
preemergence (PRE) herbicide into your soybean weed control program. Using a
planned PRE residual herbicide followed by a POST glyphosate application can
result in more consistent weed control, reduces the size and number of weeds
present at the POST application timing, and offers greater flexibility in the
POST application window. One of the concerns that many producers have in
implementing a PRE herbicide is the economics. While a PRE herbicide may
increase the cost of your weed control program, resulting benefits often make
up for the cost by increasing weed control and yield. Below are some of the
benefits realized by PRE followed by POST weed control programs.
Using a PRE herbicide
will control a number of weeds that would have emerged and competed with the
crop as it becomes established. While early-season competition may not be a factor
if the POST application is timed appropriately, (remember that weeds can
increase in size in a number of days and if you are trying to spray a large
number of acres or you become delayed in your applications due to rain)
early-season weed competition can become a problem. Remember, for timely POST
applications to avoid yield losses due to early-season weed competition MSU
recommends weeds should be controlled before they are 4-inches in height in
7.5- and 15-inch rows and 6-inches in height in 30-inch rows.
Several weed species
have continual emergence or emerge only later in the season. These species can
include: annual grasses, giant ragweed (
In
Control of perennial
weeds is more effective in the later stages of growth (bud to flower stage). Because
PRE residual herbicides will provide initial control of annual weeds the POST
glyphosate application may correspond more appropriately to the stage of growth
needed for perennial weed control.
One possible long-term
benefit from including a PRE herbicide in your weed control program is the
implementation of herbicide resistance management strategies. A PRE herbicide
would include another mode of action into the weed management program and
reduce the number of weeds present for the POST application. Ultimately, these
two benefits will relieve the selection pressure of a glyphosate-only weed management
system. This has become a much greater concern as we see more
glyphosate-resistant weeds being reported around the
Recent research conducted in the North Central Corn Belt
suggests that soybean planting populations may be able to be dialed back
somewhat without compromising yield, or more importantly, profitability. Research
conducted throughout the
What does this mean
for
Several things to consider when operating on the low end of the optimum planting population range include managing in a manner that maximizes emergence and seedling survival. Calibrate your drill or planter to ensure that seed drop is adequate and uniform across all rows. This is important to do every year as seed size and planter mechanical efficiency and wear can vary from year to year. Avoid planting when soil conditions are less than optimal to facilitate good seed to soil contact and seedling germination. Inoculate soybean seed with Rhizobium bacteria regardless of field history. Finally, if planting early in the season, consider using fungicide treated seed (be sure it is labeled for use with your soybean inoculant) to protect against soil borne root diseases.
The updates and recommendations for each topic area will be
recorded by Michigan State University Extension specialists. Messages will be
updated as often as needed to provide
The soybean hotline is a new and valuable resource for
You’ve probably read about the soybean rust found in early March on soybean residue from a bin of soybeans produced in Iowa in 2006, but if you haven’t you can read about it at the link listed here: http://www.plantpath.iastate.edu/soybeanrust/node/394 . Even though it’s early in the season, I thought that I’d start giving you some updates on what is happening with soybean rust so far this year further south.
On April 7-8, record low temperatures in the Florida
Panhandle dipped below freezing for several hours. It is not known how this
might impact the spread and build up of soybean rust on kudzu, but it will
probably slow it down for a while. Before the frost, warm temperatures had
increased the growth of kudzu throughout the Southeast. Scouting efforts are
already underway on kudzu and emerging soybeans in southern sentinel plots.
Soybean rust has been detected on kudzu in nine
Editor’s note: see the national tracking web site for soybean rust at: http://www.sbrusa.net/
Previously available only for soybean rust under a special
Section 18 emergency use label, Domark
(Valent USA Corporation) has received a new label (Section 3) allowing use on
soybeans for soybean rust (as both a preventative and a curative), and a number
of other soybean diseases.
Topguard (Cheminova, Inc., flutriafol) is a triazole
fungicide. Consult the accompanying table for a complete listing of fungicides
currently registered for soybean rust in
Soybeans: Fungicides
approved (Section 18) or registered (Section 3) for soybean rust management in
|
Active ingredient |
Product (trade name) |
Section 18 start date |
Section 18 expiration |
Section 3 Registration status |
|
azoxystrobin |
Quadris |
none |
none |
Registered
|
|
azoxystrobin + propiconazole |
Quilt |
covers use in 2005, 2006 and 2007 growing seasons |
expires 11/10/07 |
See
propiconazole. |
|
chlorothalonil |
Bravo, Echo, Equus |
none |
none |
Registered |
|
flutriafol |
Topguard |
New for 2007 covers use in 2007, 2008, and 2009 growing seasons- |
Expires 2/12/10 |
Registration
decision expected in 2009 |
|
myclobutanil |
|
covers
use in 2005, 2006 and 2007 growing seasons |
expires 11/10/07 |
Tolerance
approved; Registration decision expected in early 2007 |
|
propiconazole |
Tilt |
covers
use in 2005, 2006 and 2007 growing seasons |
expires 11/10/07 |
Registered
but final label is being reworded. |
|
PropiMax |
covers
use in 2005, 2006 and 2007 growing seasons |
|||
|
Bumper |
covers
use in 2005, 2006 and 2007 growing seasons |
|||
|
propiconazole + trifloxystrobin |
Stratego |
covers
use in 2005, 2006 and 2007 growing seasons |
expires 11/10/07 |
Registered
but final label is being reworded. |
|
pyraclostrobin |
Headline |
none |
none |
Registered |
|
tebuconazole |
Folicur |
covers
use in 2005, 2006 and 2007 growing seasons |
expires
11/10/07 |
Registration
decision expected in mid 2007 |
|
Orius |
covers
use in 2005, 2006 and 2007 growing seasons |
expires
11/10/07 |
||
|
tebuconazole + pyraclostrobin |
Headline SBR |
covers use in 2005, 2006 and 2007 growing seasons |
expires
11/10/07 |
Not
submitted for Section 3 registration |
|
tetraconazole |
Domark |
covers use in 2005, 2006 and 2007 growing seasons; 2 applications/season requested |
expires
11/10/07 |
Registered
as of 4/4/07 Note:
Rates have been decreased on the Section 3 label to 4-5 fl oz/A (from 4-6 fl
oz/A) with a maximum of two applications. |
Credit: Kent L. Smith, Plant
Pathologist, UDSA, ARS, AO Office of Pest Management Policy; Marty Draper,
National Program Leader,-Plant Pathology, CSREES; and Brian Hughes, Product
Registration Manager,
For the second year, I will be providing Michigan-specific commentary about weather conditions, wheat diseases and wheat developmental stages for the Penn State Fusarium head blight (FHB) model website. The Michigan Agricultural Weather Station Network (MAWN) weather station locations (48) have been added to the model website, providing significantly increased coverage for the state. The Penn State Model predicts the risk probability of epidemic conditions based on observed weather patterns. Separate models are used for spring and winter wheat. The winter wheat model is based on the interval of time that relative humidity is 90 percent or greater, with temperatures between 48 and 85°F (9 -30°C). Wheat is most susceptible to FHB infection during flowering. The model uses weather conditions observed during the seven days prior to the flowering date you select to predict the level of risk. You can select a risk prediction based on the previous seven days weather, six days and a 24-hour forecast, or five days and a 48-hour forecast.
The
The models have an accuracy of about 80 percent given the data used to develop and test the models. They are intended as a decision aid to be used along with other resources, such as weather forecasts, grain markets and local expert advice to help you with disease management decisions. Weather conditions that take place during flowering and grain fill of the crop are not part of the model, and could significantly affect the development of disease and accumulation of mycotoxins. This year, state-specific commentary will be available for all 24 states included in the model.
Recent freezing temperatures in
Cause: Wheat leaf rust, Puccinia triticina (fungus).
Symptoms: Infections first appear on the lower leaves. Reddish-orange
spore masses of the fungus break through the leaf surface leaving an orange
powder that rubs off the leaf. As the crop develops and matures, leaf rust
generally appears on upper leaves of plants and severity increases.
Disease cycle: The fungus can survive on wheat during a mild
winter or when covered by deep snow, or be carried in on wind currents from
more southern areas as the wheat crop develops in spring.
Conditions favoring the disease: Temperatures of 60-80ºF and conditions that
promote leaf wetness in the canopy for extended periods of time, such as rain,
ground fog and dew increase the severity of leaf rust.
Management: The primary means of controlling leaf rust
is to use resistant varieties. Scout fields from around heading to flowering.
Several foliar fungicides are labeled for control of rusts. Check the label for
application timing if a fungicide is used. The threshold for fungicide
applications is an average 5-10 pustules/ flag leaf (averaged over 30-50
leaves). Avoid spreading the disease on clothing or farm equipment. Clothing,
boots and farm equipment contaminated with rust spores should be cleaned before
entering healthy fields.
Cause: Stripe rust, Puccinia striiformis.
(fungus)
Symptoms: Stripe rust appears as long stripes of small
yellowish orange pustules on the leaves. The pustules are masses of rust
spores. It can be confused with leaf rust, but the stripe rust pustules are
arranged in rows, or stripes, while the leaf rust pustules are scattered on the
leaf. Wheat is the only host for stripe rust.
Disease cycle: Stripe rust usually arrives in the north on
wind currents from more southern wheat growing areas. It survives down south on
volunteer wheat until it can infect newly planted wheat in fall and winter.
Conditions
favoring the disease: Stripe
rust is favored by cool, humid weather. Disease development is most rapid
between 50 and 60ºF. The disease is inhibited when night time temperatures
reach 65ºF or temperatures for several days in a row reach the mid 80's.
Management: The primary means of controlling both leaf
rust and stripe rust is to use resistant varieties. Several foliar fungicides
are labeled for control of rusts. Fungicides aren’t commonly used for stripe
rust unless the disease occurs early in the season. Check the label for
application timing if a fungicide is used. Avoid spreading the disease on
clothing or farm equipment. Clothing or boots contaminated with rust spores
should be cleaned before being worn to walk through healthy fields. Likewise,
rust can spread from contaminated farm equipment. Clean contaminated equipment
before using it in a field of healthy plants.
Image Captions: Leaf
rust
Stripe rust
Photo credit for
both: Lee Siler, MS
|
Flag leaf emergence (Feekes GS 8) |
Flag leaf collar visible |
Heading (Feekes GS 10.5) |
Beginning of flowering |
|
Stratego-
trifloxystrobin+ |
Quilt-
azoxystrobin + propiconazole |
Quilt-
azoxystrobin + propiconazole (wheat only) |
Folicur-
tebuconazole |
|
|
Propimax-propiconazole |
Tilt-
propiconazole |
|
|
|
|
Headline-
pyraclostrobin |
|
|
|
|
Quadris-azoxystrobin |
|
The North Central Regional Committee on Management of Small
Grain Diseases has developed the following information on fungicide efficacy
for control of certain foliar diseases of wheat for use by the grain production
industry in the
|
Product |
|
Rate/A (fl. oz) |
Powdery
mildew |
Stagonospora leaf/glume
blotch |
Septoria
leaf blotch |
Stripe
rust |
Leaf rust |
Head scab |
|
Headline 2.09 EC |
Pyraclostrobin 23.6% |
6.0 to 9.0 |
G1 |
VG |
VG |
E2 |
E |
NR |
|
PropiMax 3.6 EC |
Propiconazole* 41.8% |
4.0 |
VG |
VG |
VG |
VG |
VG |
F |
|
Quadris 2.08 SC |
Azoxystrobin 22.9% |
6.2 to 10.8 |
F(G)3 |
VG |
VG |
E2 |
E |
NR |
|
Quilt 200SC |
Azoxystrobin 7.0% Propiconazole 11.7% |
14.0 |
VG |
VG |
VG |
VG |
VG |
NR |
|
Stratego 250 EC |
Propiconazole 11.4% Trifloxystrobin 11.4% |
10.0 |
G |
VG |
VG |
VG |
G |
NR |
|
Tilt 3.6 EC |
Propiconazole* 41.8% |
4.0 |
VG* |
VG |
VG |
VG |
VG |
F |
|
Folicur 3.6 EC4 |
Tebuconazole* 38.7% |
4.0 |
G |
VG |
VG |
E |
E |
G |
1 Efficacy categories: NR=Not Recommended; F=Fair;
G=Good; VG=Very Good; E=Excellent
2 Efficacy may be significantly reduced if solo
strobilurin products are applied after infection has occurred
3 (G) indicates greater
efficacy at higher application rates.
4 Folicur does not have a federal label, but may have
Section 18 emergency registration in some states (including
*There may be other generic propiconazole and tebuconazole products available
(check with your supplier).
This information is provided only as a guide. It is the responsibility of the
pesticide applicator by law to read and follow all current label directions. No
endorsement is intended for products listed, nor is criticism meant for
products not listed. Members of NCERA-184 assume no liability resulting from
the use of these products.
Placement of fertilizer in the seed furrow (pop-up) or 2 inches below and 2 inches (2x2) to the side of the seed can enhance early plant growth, especially in cool soil situations. Soils tend to warm more slowly under no-till and reduce tillage systems where there is more plant residue. At a 2x2 placement, there is minimal risk of any plant injury. Placement of fertilizer directly below the seed increases the injury, especially with limited soil moisture or with some fertilizers that may release volatile ammonia, such as ammonium thiosulfate.
Placing fertilizer with the seed (pop-up) has the greatest risk of injury, but can be done safely at low rates. The primary concern is with the amounts of nitrogen (N) and potassium (K2O) being applied. General guidelines from several land-grant universities are to limit the total amount of N + K2O to 5 lbs/acre for sandy soils to 10 lbs per acre for clayey soils. At 3 gallons per acre a 9-24-3 fertilizer supplies 4 lbs N + K2O per acre and a 10-34-0 fertilizer supplies 3.4 lbs N per acre. Therefore, in sandy soils the rate of liquid pop-up fertilizer should be limited to about 5 gallons per acre, whereas in loam and clay loam soils up to about 8 gallons per acre can be used.
The warm temperatures in late March may have gotten the alfalfa into trouble. Fortunately, while the weather progression from a warm, dormancy-breaking late March to a bone-chilling early April has provided reasonable cause for concern; early field observations are providing some comfort, at least for the moment.
The potential for winter injury is always difficult to predict, but we continue to try to do it anyway. Whether our predictions turn out right or wrong, perhaps there is benefit in getting us to think about it and into alfalfa fields to see how they’re progressing.
In the northern two-thirds of
In the southern third of
The critical low soil temperature that actively growing (fully out of dormancy) crowns can tolerate is unknown and certainly influenced by many factors. Our best guess for healthy plants is somewhere in the range of 20 to 25°F, but I’ve seen lower estimates. And alfalfa plants don’t go from fully dormant to fully out of dormancy overnight, at least from a chemical composition perspective. It’s likely that freezing tolerance is lost gradually as the plant comes out of dormancy and crown buds elongate to form legitimate amounts of herbage. Thus, plants that have little herbage development, say 1-3 inches, likely have more freezing tolerant crowns than those that are further along, say 6 inches or more. But as herbage development progresses and thus ground cover increases, crown insulation is also improved. Yet the herbage is fully exposed. Air temperatures in the low 20s can kill the growing point of shoots