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Pest Management & Crop Development Bulletin • No. 22 / September 1, 2006

�FOR IMMEDIATE RELEASENo. 22 / September 1, 2006

Executive editor: Kevin Steffey, Extension Entomologist

Available on the Web at http://www.ipm.uiuc.edu/bulletin

For subscription information, phone 217.244.5166, or e-mail

[email protected]

Copyright © 2006, Board of Trustees,

University of Illinois

Also in This Issue

• Soybean Aphids Still Present in Soybean Fields, But the Threat Has Dissipated, 186

• Behavior Bioassay Capable of Discriminating Between Vari-ant and Nonvariant Western Corn Rootworm Populations, 186

• Down the Home Stretch, 188• Nitrogen Rates for Corn in

Illinois, Fall 2006, 189 • Regional Reports, 190

Welcome to Fabián Fernandez

I take this opportunity to introduce you to Fabián Fernandez, our depart-ment’s recently hired Extension specialist in soil fertility and nutrient man-agement. After interviews were concluded late in 2005, Fabián accepted the position vacated by Dr. Robert Hoeft when Bob was selected as the head of the Department of Crop Sciences. Fabián’s responsibilities will be 75% Extension and 25% research, and he will focus on significant issues regard-ing soil fertility and nutrient management to address producers’ needs.

Fabián, a native of Argentina, earned his M.S. from Brigham Young Uni-versity in 2002 and recently (July) received his Ph.D. in soil fertility/plant nutrition from Purdue University. For his Ph.D., Fabián studied K bioavail-ability of no-till soils to gain a better understanding of the relationship be-tween K soil dynamics and plant development. He will build on the skills he developed at Brigham Young and Purdue to develop his Extension and research program at the University of Illinois.

Fabián has been on the job for less than a month, but he welcomes your in-put. Many of you will meet Fabián for the first time during the forthcoming “winter meeting season,” but don’t hesitate to contact him before then. His telephone number is (217)333-4424; his e-mail address is [email protected]. We are very pleased to have Fabián as a new member of the Extension team. Please help us make him feel welcome as he begins his career in Il-linois.—Kevin Steffey

Planning to Manage Western Bean Cutworm in Corn in 2007? Know Your Insects

The continued eastward spread of the western bean cutworm’s range has been a topic of significant conversation in Illinois, Indiana, Michigan, Ohio, and Wisconsin. After its somewhat “lonely” discovery in Warren County in Illinois in 2004, a network of pheromone traps has documented the western bean cutworm’s rapid spread eastward and southward through Illinois. As of August 4, 2006, western bean cutworm moths had been captured as far south as St. Clair and Washington counties in Illinois and as far east as west-ern Ohio. The numbers of moths captured in pheromone traps have been particularly large in Illinois in northwestern counties—Jo Daviess, Stephen-son, Winnebago, Carroll, Ogle, Whiteside, and Bureau.

Although the numbers of western bean cutworm moths captured this year in Illinois have been noticeable, they pale in comparison with the numbers captured in Iowa. In Illinois, only seven counties with traps have experi-enced captures of 100 to 500 moths, and none have exceeded 500. In Iowa, by contrast, most of the counties where traps are located have experienced captures of at least 100, and many of them more than 500. So we need to keep the situation in perspective.

INSECTS


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Even so, western bean cutworms will deserve management attention in some areas of Illinois in 2007. Some pro-ducers will want to consider planting a Herculex Bt corn hybrid that will control western bean cutworms (i.e., Herculex I, Herculex XTRA), whereas others may decide to address manage-ment next year by regular scouting and application of an insecticide if needed. Regardless, it is very important that overreaction not be part of the man-agement plan.

Although western bean cutworm ap-pears to be relatively widespread in Illinois in 2006, it is unlikely that the larvae have caused much damage to corn in most areas where the pest has been found thus far. We also are aware that some other ear-damaging insects have been misidentified as western bean cutworm. An individual who had examined some cornfields in Livingston County during the last week of August discovered fall army-worms and corn earworms feeding in about 20% of the ears in one area of the field. Although the damage to corn ears caused by corn earworms, fall armyworms, and western bean cut-worms is relatively similar, the insects can be distinguished from one another with certain characteristics.

As we have stated before, the western bean cutworm larva is pale tan, brown, or pink-gray and lacks conspicu-ous markings, except for short, dark stripes on the top of the first segment behind the head. The fall armyworm larva is slightly more colorful than the western bean cutworm, and it also has some distinguishing body mark-ings—three yellow-white lines along the back and a wider dark stripe on each side of these lines. Below the dark stripe on each side is a wide, wavy, yellow stripe with red splotches. In addition, a fall armyworm larva has a dark brown head with a white inverted Y on the front. Corn earworm larvae are usually more colorful than fall armyworm larvae. A corn earworm larva may be green, yellow, brown, red, or pink with longitudinal white stripes. The skin of both a fall army-

worm and a western bean cutworm is smooth, whereas the skin of a corn earworm is covered with microspines. The head of a corn earworm larva usu-ally is yellow-brown or yellow-orange and stippled, and it lacks the white in-verted Y of the fall armyworm. Marlin Rice, extension entomologist at Iowa State University, published some ex-cellent photographs of fall armyworm and corn earworm larvae in the article “Insect Injury to Mid-Season Corn” in the June 28, 1999, issue of Integrated Crop Management (www.ipm.iastate.edu/ipm/icm/1999/6-28-1999/mid-scorninj.html). Also, Kansas State University has an excellent identifica-tion key, “Identifying Caterpillars in Corn and Sorghum,” www.oznet.ksu. edu/library/entml2/s121.pdf#search=%22corn%20caterpillars%22.

Being able to distinguish among cat-erpillars that may have damaged corn ears this year may save producers money next year. Although western bean cutworms have captured a lot of attention because of their newness, mistaking corn earworms or fall ar-myworms for western bean cutworms will not aid management plans.

As the 2006 chapter on western bean cutworms in Illinois closes, we will begin to compile information from our and other states’ efforts to develop educational materials and programs. In the meantime, sharpen your insect-identification skills, and let us know what you are finding in your area.—Kevin Steffey

Soybean Aphids Still Present in Soybean Fields, But the Threat Has Dissipated

Our weekly survey of soybean aphids in 26 fields continues, but soybean development is past the stage when economic damage would occur. Al-though densities of soybean aphids approached the economic threshold of 250 aphids per plant in one field in Stephenson County on August 11 (Stephenson 7, Table 1), the density in that same field on August 21 had de-

clined to 156.1 aphids per plant. None of the densities of soybean aphids in the 26 fields surveyed from August 10 through August 22 (Table 1) reached the economic threshold. Densities in some fields continued to increase from August 10 to August 22, whereas densities in other fields either reached a plateau or declined during the same time period.

As soybeans mature and leaves begin to drop from the plants, soybean aphid colonies will produce winged aphids, which will begin leaving soybean fields in search of their overwintering host, buckthorn. Some of these flying aphids will be captured in suction traps scattered around the Midwest, and the numbers captured this fall might give us some insight into the potential population of soybean aphids in 2007. With the relative absence of multicol-ored Asian lady beetles in most areas and most soybean fields having low to moderate numbers of soybean aphids, the present outlook for soybean aphids in 2007 is good (bad for us). However, this outlook could change between now and next spring, and summer temperatures in 2007 also will have an effect. We’ll simply have to wait and see.—Kevin Steffey

Behavior Bioassay Capable of Discriminating Between Variant and Nonvariant Western Corn Rootworm Populations

For many years, entomologists have been unable to accurately discriminate between variant and nonvariant west-ern corn rootworm populations. In the most recent issue of Environmental Entomology (August 2006, Vol. 35, pages 1049–1057), Lisa Knolhoff (graduate student in the Department of Entomology, University of Illinois) and David Onstad, Joe Spencer, and Eli Levine (entomologists with the University of Illinois and Illinois Natural History Survey) reported how they could separate variant from nonvariant western corn rootworms utilizing a behavioral bioassay. As the authors indicate in their paper, this is

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Table 1. Densities of soybean aphids in 26 fields in Illinois, August 10–22, 2006.

August 10–11 August 16–17 August 21–22

County and field

number

Avg no. soy-

bean aphids

per plant1

Stage of

soybean

development2

Avg no. soy-

bean aphids

per plant1

Stage of

soybean

development2

Avg no. soy-

bean aphids

per plant1

Stage of

soybean

development2

Woodford 1 3.45 R5 14.70 R5 47.30 R6

Woodford 2 4.60 R5 8.85 R5 24.70 R6

Woodford 3 64.90 R5 54.45 R5 108.30 R6

Woodford 4 6.20 R5 10.55 R5 30.35 R6

Woodford 5 2.30 R5 2.90 R5 18.15 R6

Woodford 6 3.55 R5 13.10 R5 9.30 R6

Woodford 7 15.90 R5 10.20 R5 31.85 R5

Woodford 8 8.35 R5 11.95 R5 16.90 R5

Woodford 9 13.65 R5 9.05 R5 18.25 R5

Woodford 10 17.20 R5 19.75 R5 46.25 R5

Marshall 1 29.55 R5 62.10 R5 98.95 R6

Putnam 1 23.90 R5 26.35 R5 73.65 R6

Bureau 1 7.65 R5 13.85 R6 24.45 R6

Lee 1 16.20 R5 12.95 R5 13.35 R5

Whiteside 1 6.65 R5 8.25 R5 16.15 R5

Ogle 1 26.35 R5 23.10 R6 19.10 R5

Stephenson 1 82.25 R5 98.75 R6 44.90 R6

Stephenson 2 25.80 R5 58.95 R5 67.90 R6

Stephenson 3 35.00 R5 36.20 R5 77.45 R6

Stephenson 4 45.15 R5 40.20 R6 40.05 R6

Stephenson 5 170.55 R5 24.25 R5 62.80 R6

Stephenson 6 38.75 R5 75.90 R6 71.05 R6

Stephenson 7 191.95 R5 215.25 R5 156.10 R6

Stephenson 8 56.35 R5 87.00 R5 46.70 R6

Stephenson 9 37.45 R5 149.15 R5 94.95 R6

Stephenson 10 43.05 R5 68.35 R5 58.40 R61 Average based on numbers of soybean aphids on 20 plants.2 From Soybean Growth and Development, Iowa State University, Ames, May 2004.

the “first step in determining the ge-netic basis of rotation resistance.” By measuring the time it took for western corn rootworm adults to exit behav-ioral assay arenas, the investigators began to observe some interesting dif-ferences among beetles that had been collected from different areas (Ames, Iowa, and three Illinois locations: Monmouth, Perry, and Urbana).

The arenas were cylindrical and made of plastic mesh screen, with an open-ing in an inverted cone at the top. The bottom of the arena was made of plas-tic, with an entry hole (1.8 cm in di-ameter) into which beetles were intro-duced. In 2004, the arenas were 16 cm tall by 11 cm in diameter. The follow-ing year, the height of the arenas was extended to 42 cm. The authors made the following observation: “Results from these assays indicate that D. v. virgifera females from regions where crop rotation is no longer effective are

more active than females from regions where rotation remains effective.” Dif-ferences among variant and nonvariant populations were more evident when the bioassay was performed in the field as compared with the laboratory.

During 2004, beetles collected from Urbana were “consistently more ac-tive” than specimens obtained from Monmouth. Urbana is much nearer the geographic epicenter (Piper City, Ford County) of where it is believed the variant western corn rootworm had its origin. In 2005, western corn rootworm females collected near Ames, Iowa, were the “least active” as compared with the beetles collected from Urbana and Perry. The research-ers made these concluding statements in the abstract of their paper: “Results were consistent with the hypothesis that a loss of fidelity to corn rather than any particular attractant is the cause of rotation resistance. Behav-

ioral differences between populations of beetles in similar environments suggest that there is a genetic differ-ence between rotation-resistant and wild-type D. v. virgifera, although no specific gene or genes have yet been identified.”

The pdf version of this article is available at caliban.esa.catchword.org/vl=1413605/cl=20/nw=1/rpsv/cw/esa/0046225x/v35n4/s27/p1049.

Reference

Knolhoff, L.M., D.W. Onstad, J.L. Spencer, and E. Levine. 2006. Behav-ioral differences between rotation-resistant and wild-type Diabrotica virgifera virgifera (Coleoptera: Chrys-omelidae). Environmental Entomology 35(4): 1049–1057.

—Mike Gray


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CROP DEVELOPMENT

Down the Home Stretch

Corn is starting to reach black layer in many fields in southern and central Illinois now, more or less on sched-ule, based on the growing degree-day (GDD) requirements, at least in fields where there has been adequate water available most of the season. Physi-ological maturity refers to the point in time when the kernels no longer accumulate dry matter and, thus, that grain yield for that ear has reached its maximum. The darkened layer of cells at the base of the kernel is an indica-tion that these cells are no longer transporting sugars from the cob to the kernel. Kernels on the same ear reach black layer at different times, but it’s not necessary to shell all of the kernels and scrape their base in order to know the exact day this happened. When the husks have dried and there is no liquid at the base of the kernel, sugar move-ment has, for all practical purposes, stopped.

Under good conditions, black layer is reached when the kernels are as large as they can get, after which some sugars might continue to accumulate in the cob or stalk before leaves dry up. In fields where the crop stopped filling early due to lack of water, ker-nels eventually show the black layer typical of mature kernels, though it can take a while for the dark color to develop. The end of grain filling in such fields is forced by the end of the sugar supply from the leaves, not from the “natural” cause of having kernels reach their maximum size. We would consider such a crop to be “source limited,” since the source of sugars to fill kernels (photosynthesis) stopped before the kernels were filled.

While we normally consider corn to be source limited, meaning that kernels typically do not get quite as large as they could, there are some conditions under which kernels reach their maxi-mum size. Many people have observed this year that ears do not have grain

all the way to the end. Reasons for this are not entirely clear, especially where there was enough water avail-able during July. High temperatures and silk-eating insects probably con-tributed in most fields. In any event, as we reach the end of the filling period under good conditions, it is likely that kernels on such ears will get quite large, and if leaves remain green after black layer is reached, it is likely that kernel number, rather than photosyn-thesis, will limit yields in such fields. The only practical consequence of this will be higher yields than kernel counts might suggest. If we end up with 80,000 kernels per bushel instead of the “default” 90,000 used in the corn yield calculator, that means 11% more yield.

An indication of how good filling conditions have been in parts of Illi-nois this year is provided by some data that Eric Adee at Monmouth provided. We have a project in which we are sampling ears at seven-day intervals, drying the ears and shelling them, and taking kernel weights. During the first two weeks in August, one hybrid added a total of 126 bushels per acre, or 9 bushels per day. Rates were the same for each of the two weeks and probably represent accumulation rates near the maximum, though even then there were probably some days better than others. But a crop would have to maintain such a rate for only 33 days to produce 300 bushels per acre and for only 22 days to reach 200 bushels per acre. This is during the “linear” phase of yield accumulation, starting perhaps 10 to 15 days after the end of pollination and ending a week or so before black layer; in most cases, this would last for about 40 to 45 days. That means that we normally get fill-ing rates of maybe half the potential rates during this period. This puts some perspective on the importance of having healthy canopies and good ker-nel numbers, and also on the need for favorable temperatures and moisture.

When kernels get larger under good conditions at the end of the season, many people think of this extra yield

as coming from an “increase in test weight.” If kernels increase in weight by packing more starch into the same volume, then test weight and yield do increase together. But test weight is a measure of bulk density, while yield is based only on weight, so the two are not directly tied together. We can have very high yields without high test weight and low yields (think popcorn) with very high test weight. In fact, there is often very little correlation between test weight and yield among hybrids in our corn hybrid trials. How kernels fit together and how densely they are packed with starch determine test weight, while yield is the result of kernel number per acre and weight per kernel.

High test weights are nice because they mean we can put more “bushels” in a bin. Historically, a “bushel” was a fixed volume of grain (1.24 cubic feet), but today it refers to a fixed weight of grain (56 lb for corn). Thus the volume of a 10,000-bushel bin is about 12,400 cubic feet, but the bin will hold some 10,700 bushels of corn if the test weight is 60 lb/bushel. Be-cause 60 lb/bushel is the standard test weight for soybeans, the same bin will hold only 10,000 bushels of soybean if they are at the standard test weight. We have not paid a lot of attention to soybean test weight, but it seems to vary less than corn test weight, prob-ably because the spherical shape of the seeds means they pack together more uniformly and also because seed den-sity may vary less.

Soybean fields are starting to lose their color, but the rainfall over the past two weeks has been helpful to the soybean crop in most areas, and there is con-siderably less premature end to seed filling in soybean than in corn. The rains partially revived the potential of double-cropped soybeans, but the late flush of leaves, flowers, and pods in these fields means that they will need good filling conditions during most or all of September, possibly into October, in order to fill these pods and to make good yields. Full-season soy-beans may have lower than ideal pod

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numbers in some fields due to stress in late July, but the filling conditions have been good, and it appears that seeds will fill to their normal weight, and maybe a little above their normal weight, in fields where the canopy is still green and healthy. It would be better if daily high temperatures were higher than the upper 60s and low 70s we’re getting in much of Illinois at the end of August, but as long as good sunlight returns and night tempera-tures do not drop into the lower 50s, temperatures a little lower than normal will mean only a delay in maturity, not a loss in yield.—Emerson Nafziger

Nitrogen Rates for Corn in Illinois, Fall 2006

The nitrogen rate calculator for Illinois located at the Iowa State University website (extension.agron.iastate.edu/soilfertility/nrate.aspx) was updated this summer, and it now includes sepa-rate calculations for northern, central, and southern Illinois. We also added a handy feature that allows N price to be designated either per lb of N or as product price per ton.

It’s difficult to see, but in the lower right-hand corner of the “manila

folder” on the website is some small print that says “How to use.” Click on this for a popup that gives information about the site, the rationale used to de-velop this approach, and a map show-ing how we divided Illinois into north, central, and south. We know that these designations are less than exact, but they should work until we have data to define regions better.

This approach allows us to use current research data to suggest a range of N rates for a given set of corn and N prices. The good news is that N prices have moderated some since last winter and spring, and projected corn price for the 2007 crop might be higher than recent corn prices have been. How to guess at a price for the 2007 crop when making decisions on how much N to use this fall is not an exact sci-ence. If it helps, cash bids in central Illinois this week are running at about $2.05, the December 06 futures price is about $2.40, and the December 07 futures prices is around $2.90.

Table 2 gives suggested N rate ranges for corn following corn and for corn following soybean for different re-gions in Illinois, at three N prices and five corn prices. The N prices

of 25, 30, and 35 cents per lb are equivalent to anhydrous ammonia prices of $410, $492, and $574 per ton, respectively. Ranges for prices between these can be estimated. The N rate expected to provide the great-est return to N is in about the center of each range.

These guidelines are based on the best available data we have, but we hope to add to our confidence in them as we add to the numbers of locations we have to use in the calculations. Until then, we suggest setting N rates within these ranges based on corn and N prices. For corn following corn in fields where continuous corn has been yielding well, it may be appropriate to be toward the upper end of the range indicated.

We continue to get questions about the wisdom of fall application, and about the need to use N-Serve if applying N in the fall. On medium-textured and heavy soils, there is no strong indica-tion that fall application leads to a great deal of N loss, as long as care is taken to apply N only after the soil temperature has reached 50 degrees or less. In practical terms, that means waiting until about the last week of

Table 2. Fall 2006 nitrogen (N) rate guidelines calculated for different corn and nitrogen prices.

Corn following corn Corn following soybean

Price of applied N, $ per lb actualExpectedcorn price $0.25/lb N $0.30/lb N $0.35/lb N $0.25/lb N $0.30/lb N $0.35/lb N

Northern Illinois

$2.20 172 to 217 161 to 204 151 to 192 116 to 151 109 to 143 103 to 136

$2.40 178 to 222 167 to 209 158 to 198 120 to 154 113 to 146 107 to 139

$2.60 183 to 226 173 to 214 164 to 203 123 to 156 117 to 149 111 to 142

$2.80 187 to 228 178 to 218 169 to 207 126 to 159 120 to 151 115 to 145

$3.00 192 to 230 182 to 223 173 to 212 128 to 161 123 to 153 118 to 147

Central Illinois

$2.20 150 to 191 142 to 180 135 to 170 145 to 185 136 to 174 127 to 164

$2.40 155 to 196 146 to 184 139 to 175 149 to 189 141 to 179 133 to 169

$2.60 159 to 200 151 to 188 144 to 179 154 to 193 145 to 183 138 to 173

$2.80 163 to 204 155 to 192 148 to 183 157 to 196 149 to 186 142 to 177

$3.00 166 to 208 158 to 196 152 to 186 161 to 199 153 to 189 146 to 181

Southern Illinois

Due to risk of loss, applying N in the fall is not recommended in southern Illinois.


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October in northern Illinois and the very end of October or early Novem-ber in central Illinois. A stabilizer (N-Serve) can provide additional safety against loss, in the event that soils warm up again before they freeze up.

Calling For N Rate Volunteers

You might recall that we asked last winter for cooperators to take part in a project where we hope to get as many as 100 on-farm N rate trials, with N applied in replicated strips. Dr. Howard Brown with Growmark has been a full cooperator on this work, and we have funding from FREC (fer-tilizer checkoff dollars) to run these trials, probably for at least two more years. Cooperators will be paid a small stipend to compensate for lower yields in low-N strips.

There are about 50 of these trials on Illinois farms in 2006. The trials have gone well, and we will report on re-sults after they come in. We would like to double the number of trials for 2007. We are interested in having tri-als with fall-applied N and others with spring-applied N, depending on which practice cooperators are using. There are five N rates—0, 50, 100, 150, and 200—with three reps (strips) of each rate, randomized within three blocks, for a total of 15 strips. Strips with N applied before planting (fall or spring) will have to be in the same direction as the rows will be planted, of course, with reasonable assurance that strips where yield will be taken are fertil-ized uniformly with the correct N rate. Autosteer might help, but it is not required.

Additional N, for example that in DAP or MAP, can be used, meaning that the lowest rate might be 20 to 30 lb of N instead of zero. We would like to get 25 or more of these trials in corn fol-lowing corn, and the rest in corn fol-lowing soybean. Fields should not be ones where manure has been applied in the past 10 years.

If you or someone you work with has interest in conducting one of these tri-als, please contact one of us by email,

or phone 217-333-4424. We’ll provide additional details in the October is-sue, and again next spring.—Emerson Nafziger and Fabián Fernandez

REGIONAL REPORTS Extension center educators, unit edu-cators, and unit assistants in northern, west-central, east-central, and south-ern Illinois prepare regional reports to provide more localized insight into pest situations and crop conditions in Illinois. The reports will keep you up to date on situations in field and forage crops as they develop throughout the season. The regions have been defined broadly to include the agricultural statistics districts as designated by the Illinois Agricultural Statistics Service, with slight modifications:

• North (Northwest and Northeast districts, plus Stark and Marshall counties)

• West-central (West and West South-west districts, and Peoria, Woodford, Tazewell, Mason, Menard, and Logan counties from the Central district)

• East-central (East and East South-east districts [except Marion, Clay, Richland, and Lawrence counties], McLean, DeWitt, and Macon counties from the Central district)

• South (Southwest and Southeast districts, and Marion, Clay, Richland, and Lawrence counties from the East Southeast district)

We hope these reports will provide additional benefits for staying current as the season progresses.

Northern Illinois

Several widespread thunderstorms have gone through the northern region during the past two weeks, with some areas receiving 3 inches and most at least 1 inch. Some areas received heavy, rapid rainfall on August 25 and 28, which resulted in rapid surface runoff.

Several Extension educators have reported increased incidence of sudden

death syndrome in soybeans and gray leaf spot in corn. Also, white mold disease is evident in soybeans in some areas. Soybean aphids are still present, but populations have declined during the last week.

Jim Morrison, Extension educator, reminds growers that for hay fields that will be in production in 2007, the last harvest during the growing season should be made by September 5 for the northern quarter of the state.

West-Central Illinois

Varying amounts of rainfall, rang-ing from 1/2 inch to over 3 inches, occurred during the first part of the week.

Most producers are completed with silage harvest, although some corn has not matured enough yet. Those fields should be ready soon. Most cornfields are at or very near black layer.

A few producers have begun to harvest corn in fields that died prematurely due to lack of moisture. Concerns about lodging (which has occurred in varying degrees already in these fields) and low moisture (low 20s) brought out the combines. Yield reports are varying, with monitors showing from 5 to 200-plus bushels. Several plots have been harvested, with yields rang-ing from 100 to 150 bushels per acre. Some of the more stressed fields are reporting test weights in the low 50s.

Gray leaf spot is not uncommon in many fields.

Soybean maturity ranges from R5 to R7. There are a number of small (3/4-inch) pods on the later-maturing plants that will certainly benefit from the recent rains. SDS and charcoal rot can be found in many parts of the region. In some cases, plants exhibiting both symptoms are in the same field and next to each other. Septoria leaf spot and downy mildew are also noted in some fields.

Soybean aphids are common in some areas but have yet to reach economic levels.

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In those areas that have received rain-fall during August, pasture growth has been noted and welcomed. Other areas are still feeding a high percentage of the cattle herds with hay.

Contributing Authors

Fabián Fernandez ([email protected]), Extension Crop Sciences, (217)333-4426

Mike Gray ([email protected]), Ex-tension Entomology, (217)333-6652

Emerson D. Nafziger ([email protected]), Crop Sciences, (217)333-4424

Kevin Steffey ([email protected]), Extension Entomology, (217)333-6652


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U of I Extension Newsletter ServiceUniversity of Illinois at Urbana-Champaign528 Bevier Hall, MC-184905 S. Goodwin AvenueUrbana, IL 61801

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Copyright © 2006, Board of Trustees, University of Illinois

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