1

Number 343 March 30, 2012

1. Bird cherry-oat aphids and greenbugs on wheat _____________________________________ 1

2. Relationship between earthworms and agricultural practices ___________________________ 4

3. Pesticide label web sites _________________________________________________________ 6

4. Corn planting: How early is too early?_____________________________________________ 7

5. Wheat disease report ___________________________________________________________ 9

6. The rapid development of alfalfa weevils ___________________________________________ 9

7. Kansas Flint Hills Smoke Management Plan: April non-agricultural burning restrictions __ 11

8. Comparative Vegetation Condition Report: March 13 – 26____________________________ 13 1. Bird cherry-oat aphids and greenbugs on wheat Bird cherry-oat aphids and greenbugs have been found on wheat fields in Kansas recently. Should producers spray their fields to control these insects? Spraying now may be justified if numbers are high enough to prevent any further direct injury caused by these insects. Natural enemies, both lady beetles and parasitoid wasps, are also present and growing conditions are good. So, while treating for aphids is always a possibility, it has not often been justified. It takes a pretty high population of aphids (30-50/tiller) with no lady beetles or mummies (indicating the wasp is active) and less-than-ideal growing conditions before an insecticide application to prevent damage from aphid feeding is justified. The discussions below for each species give a little more detail on the kind of direct feeding injury the aphids can cause, and economic threshold levels. Both the bird cherry-oat aphid and greenbug can transmit a virus that causes barley yellow dwarf, but a foliar insecticide application now will not guarantee the disease has not, nor will be, transmitted to the plants.

Bird cherry-oat aphid The bird cherry-oat aphid is one of the largest aphids to be found on wheat in Kansas and varies in color depending on the temperature and its stage of growth. Nymphs are usually pale yellowish-green, darkening as they mature to a deep olive green in the adult stage. Under very warm conditions, adults may be much paler in color. When large colonies persist on wheat plants past the boot stage they can cause the flag leaf to twist into a corkscrew shape that can trap the awns, resulting in 'fish-hooked' heads.

2

Female bird cherry-oat aphid (right) and her nymph.

Photo by Phil Sloderbeck, K-State Southwest Research-Extension Center. When the climate is sufficiently warm, asexual reproduction can continue year-round on wheat, oats, and other cereal grains. Asexual reproduction of the bird cherry-oat aphid occurs in Oklahoma and possibly in southern Kansas, and these populations are likely responsible for the migrants that colonize more northern wheat fields very early in spring, often while snow is still on the ground. At one time, it was thought that the bird cherry-oat aphid caused very little direct yield loss to wheat except by vectoring BYDV. However, more recent research information from Oklahoma State University and the USDA-ARS suggest that the bird cherry-oat aphid is almost as damaging to wheat yield as is the greenbug. The data shows that if populations exceed 20 aphids per tiller before the boot stage, (400 aphids per foot of row) for 10 days, a 5% yield loss could be expected. If populations exceed 40 aphids per tiller for 10 days, (800 per foot of row) before boot, a 9% yield loss could be expected. Although its feeding causes no chlorosis or other visible damage to wheat plants, heavy infestations can also reduce grain quality, affect protein content and test weight, and even reduce protein assimilation by grazing cattle. Still, the bird cherry-oat aphid causes the most damage by vectoring plant viruses, especially BYDV. Although the hot summer weather in Kansas is usually effective in decimating aphid populations, bird cherry-oat aphid can temporarily avoid extremes of temperature by feeding on the lowest parts of the stalk, at or below ground level. It is also able to feed actively in weather too cold for other aphids, such as the greenbug, enabling the bird cherry-oat aphid to effectively colonize seedling wheat quite late into the fall. The bird cherry-oat aphid is usually held below economic injury levels by natural enemies such as lady beetles, lacewings, hover flies, and parasitic wasps. However, conditions that favor outbreaks of greenbug or Russian wheat aphid (for example, an abrupt shift back to cold temperatures after a

3

warm spell in spring) also benefit the bird cherry-oat aphid. The bird cherry-oat aphid will often be found forming mixed colonies with these aphids when they are abundant. In such cases, decisions to apply pesticides should be driven by the numbers of those direct-damaging species and materials applied to control them should be equally effective against bird cherry-oat aphid. If bird cherry-oat aphid is present alone, count the number of aphids present on each of a series of 25 - 50 randomly selected tillers across a zigzag transect of the field. Treatment with an insecticide broadly labeled for aphid control on wheat can be considered if an average of 50 or more aphids per tiller is present from boot stage up until heading. However, treatment with contact insecticides will not reduce the incidence of virus transmission.

Greenbugs Greenbugs are pale green aphids with a dark green line down the back and antennae as long as the body. Greenbugs usually prefer to feed on the underside of lower leaves. Damage can occur in fall or spring, with tiny reddish spots on leaves signaling a beginning infestation. Later, infested leaves turn yellow, then reddish brown and eventually die. In the field, damage often appears as yellow or reddish-brown irregularly shaped patches that can spread to become almost field-wide.

Greenbugs on wheat. Photo by Phil Sloderbeck, K-State Southwest Research-Extension Center.

The guidelines below are useful in estimating the need for greenbug control. For convenience, damaging levels are expressed as the number of greenbugs per foot of row, but in assessing the need for control, the thickness of the stand also becomes important. 50 greenbugs per foot of row in a thin stand would be more serious than in a thick stand because the number of aphids per plant would be greater. Similarly, larger plants can tolerate somewhat larger numbers of greenbugs before significant damage occurs.

4

Approximate Damaging Levels of Greenbugs Stage and development of plants No. of greenbugs per linear foot Seedlings, thin stands less than 3 tillers 50 3- to 6-inch wheat, 3 tillers or more 100 to 300 6- to 10-inch wheat 300 to 500 Overwintering greenbugs can rapidly develop into damaging infestations during warm periods in February and March, and close surveillance of fields is necessary if greenbugs are present. Beneficial insects such as parasitic wasps and ladybeetles become increasingly effective in reducing greenbug populations around mid-April. Once parasitism levels reach between 10 and 15 percent, greenbug populations usually decline fairly rapidly. Greenbug control on small grains is occasionally needed during periods of relatively cool weather (below 60°F, but above freezing). Experience has shown that good results are possible under these conditions with some, and perhaps most, of the recommended insecticides. Dimethoate may be an exception, however. It may not give acceptable control below 60°F. Oklahoma State University has developed a sampling program called “Glance ‘n’ Go,” which calculates a greenbug threshold based on the cost of control, the market value of wheat and the month of the year. For more information on their greenbug pest management decision support system, see the web site at: http://entoplp.okstate.edu/gbweb/. Consider avoiding pesticide applications when beneficial insects such as lady beetles and parasitic wasps are active, as these are often abundant enough to prevent greenbugs from reaching damaging levels. Augmenting greenbug predators such as ladybeetles or lacewings by importing and releasing is not advisable. For more detailed information on bird cherry-oat aphids and greenbugs, see: http://www.entomology.ksu.edu/DesktopDefault.aspx?tabindex=185&tabid=487 http://www.entomology.ksu.edu/DesktopDefault.aspx?tabindex=189&tabid=489 For specific treatment options, see K-State publication “Wheat Insect Management 2012” MF-745 at: www.ksre.ksu.edu/library/ENTML2/MF745.PDF -- Jeff Whitworth, Extension Entomologist jwhitwor@ksu.edu -- Doug Shoup, Southeast Area Crops and Soil Specialist dshoup@ksu.edu 2. Relationship between earthworms and agricultural practices In Darwin’s writings (1881) he states “The plough is one of the most ancient and most valuable of man’s inventions; but long before he existed the land was regularly ploughed, and still continues to be thus ploughed by earthworms”. While the plow is equated to the earthworm in the above quote, the effect of the plow and other agricultural practices on the earthworm was not considered.

5

What effect does tillage have on earthworm populations? Earthworm populations generally become reduced in cultivated agricultural fields. Several explanations for the decline and loss of earthworms have been proposed: 1) Tillage implements cause physical injury to earthworms, resulting in mortality. 2) Reductions in residue and soil organic matter associated with long-term tillage restrict food supplies. 3) A change in soil temperature resulting from the loss of insulation provided by the vegetation. 4) Increased predation from birds when the soil is turned over. It is likely a combination of these factors that leads to reduced earthworm populations. In studies comparing adjacent cultivated and uncultivated soils population reductions are wide-ranging. In one 5-year study cultivation reduced the population by 70% (Evans and Guild 1948, Ann. Appl. Biol., 35: 485-493) but in a different series of 25-year studies the population was only reduced between 11 and 16% (Low 1972, J. Soil Sci., 363-380). When tillage practices are reduced or eliminated as a result of conversion to a minimal or no-till system, earthworm populations generally begin to increase. Earthworms play an important role in no-till systems as they redistribute organic matter, are important in soil fertility, and their burrows play an important role in soil aeration and drainage. How do fertilizer and lime affect earthworm populations? There is only limited information in the literature about the effect of anhydrous ammonia on earthworms. It is safe to say that earthworms in direct contact with the concentrated ammonium plume of the injection band are eliminated, but what effect this has on the overall earthworm population is yet unknown. In general, fertilizer and lime may affect earthworms either directly through, for example, a change in soil pH or maybe toxicity (ammonium radical) or indirectly through a change in the amount and quality of the plant vegetation. The toxicity of the ammonium radical on earthworms was documented in a series of fertility studies examining sulfate of ammonia in the late 1940’s and early 1950’s. These studies also identified increased soil acidity from the fertilizer as having a negative effect on the earthworm populations. As a general rule, earthworms tend to avoid acidic soils (pH < 4.0-4.5) possibly because of calcium requirements. In pasture settings earthworm populations have generally been reported to increase in response to lime application. Do any certain crops tend to affect earthworms populations? The general conclusion is that the particular crop is not as important as the availability of food (organic matter) for the earthworms. Inputs of materials rich in organic matter, such as animal manure or municipal biosolids, or crop rotations involving a hay or pasture phase tend to increase earthworm populations. In contrast, row cropping systems that remove residue and deplete soil organic matter tend to have decreased earthworm populations. In one comprehensive study, it was observed that the supply of organic matter to the soil was critical to building earthworm populations and that cereal crop residues were more beneficial than quickly decomposing legume residues (Span. Shell Chem. Co., 26: 106-108).

6

Is there anything producers can do to increase earthworm populations? Based on the available information producers can encourage earthworm population by reducing tillage, soil testing and liming as needed to maintain optimal soil pH, and ensuring that sufficient organic matter is being returned to the system through use of crop rotations and minimizing crop residue removal. -- Peter Tomlinson, Environmental Quality Specialist ptomlin@ksu.edu 3. Pesticide label web sites Questions about pesticide uses and restrictions often require the need to look up pesticide labels. All pesticide containers are sold with pesticide labels, but when you don’t have access to those, labels can also be easily accessed via the internet. Below are some websites that can be very useful to view and search for pesticide label information. * CDMS (http://www.cdms.net/LabelsMsds/LMDefault.aspx?t=) This is the site I most commonly use because it is very simple and straightforward if you know what you are looking for. You can browse through company products or simply type in the name of a product you are looking for and it will bring up a list of products, labels, supplemental labels, and MSDS sheets to choose from. It includes most major pesticide companies, but there are some generic companies and products that are not included. * Greenbook (http://www.greenbook.net/) Those folks that were around before the internet may remember the big green books that could be purchased which contained pesticide labels from most of the major pesticide companies. The Greenbook website is the internet version of that manual. It probably has more search capabilities than CDMS, but is a little more cumbersome to use. Like CDMS, Greenbook does not include all generic companies. Greenbook may include some that CDMS does not include and vice versa. * Agrian (http://agrian.com/labelcenter/results.cfm) Agrian is a newer site that has some excellent searchable capabilities and a much more comprehensive list of chemical companies. When you go to the opening page of the Agrian website, there is a label lookup box to access the pesticide label site. Once there, if you know what product you want to view, simply type that in the search box and proceed. If you want to search by crop, pest, active ingredient, manufacturer etc., click on the advanced search button and proceed. It often takes more steps to access the labels at this site than the other sites, but it is more comprehensive. * National Pesticide Information Retrieval System (http://state.ceris.purdue.edu/) This is a website hosted by Purdue University that provides information on registration and licensing of pesticides by individual states. I sometimes use this site to determine if a product I’ve never heard of, such as products sold over the telephone, are actually registered in Kansas. You can also view how many products with a given active ingredient are registered in Kansas. For example, over 300 different products containing glyphosate are actually registered for sale in Kansas. -- Dallas Peterson, Weed Management Specialist dpeterso@ksu.edu

7

4. Corn planting: How early is too early? With the warm temperatures this spring, many producers are itching to get the corn planters in the field. The widespread rains received last week put the brakes on corn planting in much of the state for a while, but as soon as soils are dry enough, producers will be asking: How early is too early to plant corn? We often recommend using soil temperatures as a guide for timing corn planting. Generally, corn needs average soil temperatures at or greater than 50 degrees F to germinate and emerge. How deep should soil temperature be measured, and at what time of day? Although the seed and seedling are usually in the top 2 to 3 inches, we usually use the 4-inch soil temperature because it is less affected by the daily swings in temperature. Soil temperature averages are calculated from the maximum and minimum for each day. If you take the soil temperature before noon, that is a fairly good indicator of minimum soil temperature because of the lag in soil temperature change on a typical day. This timing would be the most conservative indicator of temperatures adequate for germination and growth. Examining the 4-inch soil temperatures for the past week (Table 1), it is evident that average soil temperatures exceeded the recommended 50 degree minimum at all stations. Note that the cooler soils are in Western Kansas, where the frost-free date is also later.

Table 1.WEEKLY SOIL TEMP. AT 4 INCH DEPTH WEEK OF March 18 TO March 24

AND 95% FROST FREE DATE PROVIDED BY WEATHER DATA LIBRARY

KANSAS STATE UNIVERSITY Station Average

Weekly Max

Average Weekly

Min

Weekly Ave

95% Frost Free Date

Colby 55.7 48.1 52 5/22 Garden City 54.2 48.9 52 5/10 Hays 54.8 49.7 52 5/17 Hutchinson 57.3 53.2 55 5/6 Manhattan 59.1 55.2 57 5/9 Ottawa 63.3 54.5 59 5/2 Parsons 57.2 53.3 55 4/27 Powhattan 63.3 55 59 5/14 St. John 56.5 53.4 55 5/13 Scandia 59.6 50.2 55 5/5 Silver Lake 60.5 56.2 58 5/10 Tribune 56.3 47.7 52 5/24

However, soil temperature at planting is only part of the story. Temperatures must continue to increase beyond 50 degrees F for corn growth and development to continue at a normal pace. Early-planted corn may be susceptible to damage from late-spring freeze events. Table 1 also includes the date when chances of avoiding freezing temperatures (32 degrees) reach 95%. There is still a 5%

8

chance of having a freeze after that date. These are later than typical planting dates for these locations because temperatures must be less than 28 degrees F for several hours for plants to be damaged seriously. It usually takes several days for corn plants to emerge, and even after emergence, the growing point is below the soil surface and protected from freezing air temperatures. Deciding how early to plant eventually comes down to how risk-averse each producer is.

The long-term forecast for the area may be helpful. The one-month temperature probability outlook produced by the National Weather Service Climate Prediction Center (http://www.cpc.ncep.noaa.gov) indicates that temperatures for Kansas are more likely to be above normal than equal to or below normal for the next 30 days. This bodes well for the likelihood of an early corn planting to survive. A few years ago, a series of experiments looked at early planting at Hesston, Ottawa, and Manhattan. Target planting dates were March 15, April 1, and April 15. Corn was planted at or near these dates regardless of soil temperatures. The response to planting date depended on year and location: • Mid-March planting generally did not reduce yield except with the late freeze in 2007, which

resulted in 0 bushels/acre at all locations. This was an unusual freeze event with temperatures in the teens for several hours on three successive nights. The next planting date, which was planted in early to mid-April, produced reasonable yields and was significantly superior to late-April and May planting dates.

• Mid-late March planting provided a yield benefit compared to later plantings in a drought year at Hesston (2006).

• Corn planted in mid-March 2008 emerged within a couple of days of the corn planted in early April. This was associated with cool temperatures after planting.

• The early April planting date was most consistent across locations and years. It avoided freeze damage in 2007 and yield reductions occasionally seen for later dates.

-- Kraig Roozeboom, Crop Production and Cropping Systems Specialist kraig@ksu.edu -- Mary Knapp, State Climatologist mknapp@ksu.edu

9

5. Wheat disease report Stripe rust and leaf rust remain active in the southern Great Plains. Reports from Texas indicate the both diseases are now severe in research plots in parts of that state. These reports are important because outbreaks of disease in Texas or Oklahoma are strongly associated with outbreaks in Kansas. The population of the stripe rust fungus appears to be changing again. As you may recall, in 2010 stripe rust was causing major problems on wheat varieties with the resistance gene Yr17 that is present in most varieties with Jagger in their background. Many growers have shifted their production to varieties that appeared resistant to stripe rust, including TAM111, Everest, and Armour. The information available from Texas indicates that stripe rust is now able to overcome the resistance in these varieties. Stripe rust was observed in Sedgwick County on March 28. Gary Cramer, Sedgwick County agent, reported finding low levels of stripe rust in a field of Everest. The disease was present in the mid-canopy of a production field west of Wichita. The wheat in this field was near flag leaf emergence at the time stripe rust was detected. Stripe rust was also detected in research plots near Manhattan this week. The stripe rust in Manhattan was found in the variety 2137, which is known to be susceptible to the disease. The immediate forecast is for continued warm weather, which may slow the development of stripe rust to some degree. However, temperatures are predicted to become cooler early next week, which may stimulate additional disease development. Leaf rust was detected in research plots near Manhattan on March 29. The incidence of leaf rust was very low (<1 percent) in these plots. The wheat in this field was at flag leaf emergence and leaf rust was found in the mid-canopy. The infection was on 2137, which is known to be susceptible to leaf rust. Severe tan spot was reported in Riley County. This field was planted no-till back into wheat residue from last year. Powdery mildew continues to increase in many areas. Producers should be checking their wheat fields for symptoms of disease as the wheat approaches the flag leaf emergence and heading stages of growth. Fungicides may be needed if disease is present on the upper leaves prior to heading. A new K-State Research and Extension publication, Evaluating the Need for Wheat Foliar Fungicides, MF-3057, is now available at local county and district offices, and at: http://www.ksre.ksu.edu/library/plant2/mf3057.pdf -- Erick DeWolf, Extension Plant Pathology dewolf1@ksu.edu 6. The rapid development of alfalfa weevils Alfalfa weevils are rapidly developing across the state. This infestation should be winding down in the next 7-14 days at these summer-like temperatures, as pupation has started and there are even a few newly emerged adults. Infestations in central Kansas are the worst I have ever seen. Some fields have 6 to 12 larvae per stem. An entire plant can be skeletonized in only 2 days at these levels. When spraying for alfalfa

10

weevils, don’t be too quick to evaluate the effectiveness of insecticide applications. Sometimes it may take 36 to 48 hours for the insecticide to be effective, especially with the numbers we are seeing. All these insecticides are contact insecticides and some of these larvae are well-hidden and protected inside terminals and leaves. It can take a while for the larvae to move around enough to come into contact with the insecticide. Most infested stems have had multiple larvae simply because that is where the female weevil deposited a clutch of eggs last fall and they all hatched together. I have been getting questions about the use of chlorpyrifos, or products containing chlorpyrifos, relative to the legality of making a second application, if needed, per cutting. This question has arisen because of the early egg hatch and the potential length of time between this and swathing, which usually doesn’t occur until at least late April. Hopefully, multiple applications won’t be necessary but they are allowed according to the label.

Alfalfa weevil damage in an untreated strip of a Dickinson County field, March 29, 2012. Photos by Jeff Whitworth, K-State Research and Extension.

11

Alfalfa weevils captured by sweeps taken from the untreated portion of the field above. -- Jeff Whitworth, Extension Entomology jwhitwor@ksu.edu -- Holly Davis, Insect Diagnostician holly3@ksu.edu 7. Kansas Flint Hills Smoke Management Plan: April non-agricultural burning restrictions The Kansas Flint Hills Smoke Management Plan is entering its second year in 2012. This comprehensive plan is designed to minimize the movement of concentrated smoke plumes into large metropolitan areas through voluntary participation. All Flint Hills landowners and managers who conduct prescribed burns should know what is in this plan. To help educate all those affected, a series of radio interviews is being broadcast weekly each Monday on K-State’s Agriculture Today talk show. These programs will explain the many aspects of the new plan. Agriculture Today is part of the K-State Radio Network. The broadcast interviews are podcast online at www.ksre.ksu.edu/news/DesktopDefault.aspx?tabid=66. The following is a slightly edited transcript of the first in the 2012 series of Agriculture Today radio broadcasts on the Kansas Flint Hills Smoke Management Plan. This is an interview with Miles Stotts, Kansas Department of Health and Environment environmental scientist, conducted by Eric Atkinson of the K-State Radio Network.

12

Q: The April regulations on burning put into place last year as part of the Flint Hills Smoke Management Plan are very important to those outside of agriculture. Can you fill us in on that? A: The primary focus of burning in the spring in Kansas tends to be agricultural burning. But we also have a lot of burning done by municipalities and people who want to clean up debris. We took a look at the open burning regulations and how that is managed in light of air quality concerns in metropolitan areas. We came up with an approach that leaves open burning in April for the ranchers. We want the ranchers to be able to do what they need to do in April to keep their resources in good condition. Q: What specifically do the restrictions say? A: It is more or less a ban on non-agricultural burning in April. There are some exceptions. The gist of the regulation is that a person cannot open burn anything other than pasture during April in several counties, including Butler, Chase, Chautauqua, Cowley, Elk, Geary, Greenwood, Johnson, Lyon, Marion, Morris, Pottawatomie, Riley, Sedgwick, Wabaunsee, and Wyandotte. We include the three most populous counties in the state as a matter of balance. Because of the concentration of people in those areas and because that’s where we have the greatest air quality concerns, we felt like it was important to ask those folks to avoid burning excessively during April as well as asking those in the Flint Hills to limit their burning to essential agricultural burning. We do have some exceptions. For example, folks who want to do some fishing or camping early in the spring are allowed to have a camp fire. In our regulations we call that burning for “ceremonial” purposes. We also make some provisions for emergency burning. We ask that folks go through the KDHE district offices or through their local fire department. Many communities have some additional restrictions in addition to KDHE’s requirements under the open burning regulations. This is a state regulation and a work in progress. We’re always trying to make it work better. This will be the second year that this particular restriction has been in place during April. Things seemed to go pretty well last year. I think folks are now planning ahead and understanding that if they have trees and brush that need to be disposed of with open burning, then they need to do that in either March or May. Q: Many rural residents take care of their household waste by using burn barrels. Is that regulated by the April open burning restrictions? A: Burning trash is regulated year-round, but it is allowed. In that particular case, the local ordinance takes precedence. So if your local town, township, or county has a regulation that prohibits open burning of trash, then that takes precedence over state regulations. But state regulations do allow open burning of trash from a household of up to a quadraplex. So a person can burn their own household trash or storm debris even during April, if necessary, under other regulations. Q: Where can people find out more about these regulations? A: KDHE’s Bureau of Air maintains a web site at kdheks.gov. On that web site, look for “Environment” and “Air” tab. Under that tab there is another tab for open burning. That will lead you to the regulations. There is also a great web site as part of the new smoke management plan -- ksfire.org. -- Steve Watson, Agronomy e-Update Editor swatson@ksu.edu

13

8. Comparative Vegetation Condition Report: March 13 – 26 K-State’s Ecology and Agriculture Spatial Analysis Laboratory (EASAL) produces weekly Vegetation Condition Report maps. These maps can be a valuable tool for making crop selection and marketing decisions. Two short videos of Dr. Kevin Price explaining the development of these maps can be viewed on YouTube at: http://www.youtube.com/watch?v=CRP3Y5NIggw http://www.youtube.com/watch?v=tUdOK94efxc The objective of these reports is to provide users with a means of assessing the relative condition of crops and grassland. The maps can be used to assess current plant growth rates, as well as comparisons to the previous year and relative to the 21-year average. The report is used by individual farmers and ranchers, the commodities market, and political leaders for assessing factors such as production potential and drought impact across their state. The maps below show the current vegetation conditions in Kansas, the Corn Belt, and the continental U.S, with comments from Mary Knapp, state climatologist:

14

Map 1. The Vegetation Condition Report for Kansas for March 13 – 26 from K-State’s Ecology and Agriculture Spatial Analysis Laboratory shows NDVI values continue to increase, particularly in the central and southeastern areas of the state. The Flint Hills region is showing lower photosynthetic activity than areas that have a heavier concentration of winter wheat. In Western Kansas, where nighttime low temperatures have been cooler, there has been less biomass production.

15

Map 2. Compared to the previous year at this time for Kansas, the current Vegetation Condition Report for March 13 – 26 from K-State’s Ecology and Agriculture Spatial Analysis Laboratory shows much greater photosynthetic activity. The Eastern Divisions show the greatest increase in NDVI values, while North Central, Northwest, and Southwestern Divisions are at or slightly above last year’s level. The sharp diagonal boundary in the map is an artifact of using images acquired on different dates. The image on the left was acquired earlier in the map development period than the image on the right, so plant development is a bit more advanced on the right than on the left side of the splice line.

16

Map 3. Compared to the 23-year average at this time for Kansas, this year’s Vegetation Condition Report for March 13 – 26 from K-State’s Ecology and Agriculture Spatial Analysis Laboratory shows that NDVI values statewide are greatly above average. Northwest Kansas and parts of north central Kansas show the least departure from average. These are areas that missed out on much of the winter moisture, are currently rated as abnormally dry on the U.S. Drought Monitor. Southwest Kansas, while slightly above average, doesn’t see the much-greater NDVI values present in south central Kansas. This is a result of the lesser rainfall and slightly cooler temperatures in southwestern Kansas. Much of southwestern Kansas is still in severe drought.

17

Map 4. The Vegetation Condition Report for the Corn Belt for March 13 – 26 from K-State’s Ecology and Agriculture Spatial Analysis Laboratory shows that snow is no longer a factor in the Corn Belt, except along the northeastern areas. Photosynthetic activity has increased, with the greatest values seen in south central Kansas, southwestern Missouri, and central Kentucky.

18

Map 5. The comparison to last year in the Corn Belt for the period March 13 – 26 from K-State’s Ecology and Agriculture Spatial Analysis Laboratory shows much greater NDVI values along the northern portions of the Corn Belt. As mentioned in earlier updates, this is principally due to less snow cover this year than normal. The increased photosynthetic activity in the southern Corn Belt is the result of milder and wetter conditions. Much of the vegetation in the southern portion of the Corn Belt has broken dormancy earlier. As soil temperatures continue to warm, the major concern is for freeze damage to early vegetation.

19

Map 6. Compared to the 23-year average at this time for the Corn Belt, this year’s Vegetation Condition Report for March 13 – 26 from K-State’s Ecology and Agriculture Spatial Analysis Laboratory shows greater-than-average photosynthetic activity across much of the northern and southern stretches of the Corn Belt. For the northern portions, particularly in Minnesota, Wisconsin and Michigan, the difference is due to lesser snow cover. In western North Dakota, South Dakota, and the southern portions of the Corn Belt, the increase is due to extremely mild temperatures. Temperatures averaged 18 to 24 degrees above normal for the end of March.

20

Map 7. The Vegetation Condition Report for the U.S. for March 13 – 26 from K-State’s Ecology and Agriculture Spatial Analysis Laboratory shows that snow cover across the lower 48 states continues to shrink. Increased photosynthetic activity continues to progress northward. Greatest photosynthetic activity can be seen from eastern Texas across the Gulf Coast states. Mild temperatures and favorable moisture has fueled plant development in these areas.

21

Map 8. The U.S. comparison to last year at this time for the period March 13 – 26 from K-State’s Ecology and Agriculture Spatial Analysis Laboratory shows that much greater NDVI values can be seen along the northern U.S. and through the central and southern U.S. The increased photosynthetic activity in the central states, from Kansas and Missouri southward to Texas and Louisiana, are the result of a much more favorable moisture environment. The drought areas of Kansas, Oklahoma, and Texas have been greatly reduced. In the eastern areas, excessive moisture is not as large of an issue as it was last year.

22

Map 9. The U.S. comparison to the 23-year average for the period March 13 – 26 from K-State’s Ecology and Agriculture Spatial Analysis Laboratory shows that the southern areas have much greater photosynthetic activity than average. This is due mainly to warmer temperatures and favorable moisture. In contrast, the higher NDVI values in the Northeast and Mountain West are due primarily to lower snow cover. Particularly noticeable are the increased NDVI values from the Laramie Basin in Wyoming southward into northern New Mexico. Snow cover is just 33% of normal in the Central Rockies during this period, compared to 87 percent last month. Note to readers: The maps above represent a subset of the maps available from the EASAL group. If you’d like digital copies of the entire map series please contact us at kpprice@ksu.edu and we can place you on our email list to receive the entire dataset each week as they are produced. The maps are normally first available on Wednesday of each week, unless there is a delay in the posting of the data by EROS Data Center where we obtain the raw data used to make the maps. These maps are provided for free as a service of the Department of Agronomy and K-State Research and Extension. -- Mary Knapp, State Climatologist mknapp@ksu.edu -- Kevin Price, Agronomy and Geography, Remote Sensing, Natural Resources, GIS kpprice@ksu.edu -- Nan An, Graduate Research Assistant, Ecology & Agriculture Spatial Analysis Laboratory (EASAL) nanan@ksu.edu

These e-Updates are a regular weekly item from K-State Extension Agronomy and Steve Watson, Agronomy e-Update Editor. All of the Research and Extension faculty in Agronomy will be involved as sources from time to time. If you have any questions or suggestions for topics you'd like to have us address in this weekly update, contact Steve Watson, 785-532-7105 swatson@ksu.edu, or Jim Shroyer, Research and Extension Crop Production Specialist and State Extension Agronomy Leader 785-532-0397 jshroyer@ksu.edu