Increased Insect Densities Reflected in Annual Corn and Soybean Survey

 

Thirty-six counties representing the nine crop reporting districts were surveyed at the end of July/beginning of August as part of our annual statewide corn and soybean survey. The surveys were performed by sampling five corn and five soybean fields per county. For the past several years (2011, 2013–2017), surveys in corn and soybean fields have been conducted with the goal of estimating densities of common insect pests. The estimates provided in this article should not be considered a substitute for scouting individual fields and making informed pest management decisions—even areas of the state that appear to be at low risk could have contained fields with high densities of a given insect pest.

Crop Reporting Districts

Figure 1. Illinois crop reporting districts surveyed during 2017 annual corn and soybean insect survey.

 

Western corn rootworm beetles were sampled in cornfields by counting the number of beetles on 20 consecutive plants beyond the end rows of a given field—a beetle per plant average was calculated for each field. A mild winter followed by favorable conditions at egg hatch and adult emergence helped the small populations from 2016 gain some traction in 2017 (Table 1). Per plant averages are up compared to recent years, though looking at the big picture, these numbers are still considered low. The district average from the northeast (1.95 beetles per plant), was affected by a single field in LaSalle county that average 7 beetles per plant which leads to a very important point to consider with this survey. Fields are randomly selected. We have no knowledge of insect management strategies that are used – soil insecticides, transgenics, or foliar applications.

Table1

Within an adjacent soybean field, 50 or 100 sweeps were performed on both the exterior of the field (outer 2 rows) and interior (at least 12 rows beyond the field edge) using a 38-cm diameter sweep net. The insects collected in sweep samples were identified and counted to provide an estimate of the number of insects per 100 sweeps (Tables 2 and 3).

Table2

 

Table3

The number of western corn rootworm adults in soybean fields throughout the state was low as well. The greatest number of beetles in soybeans occurred in McLean County, 8.00 beetles per 100 sweeps. All other counties sampled had fewer than 5 beetles per 100 sweeps (range of 0 to 2.4 per 100 sweeps).

Japanese beetles continued to increase in number from 2016 in the western part of Illinois. Both Fulton and McDonough counties recorded over 200 beetles per 100 sweeps in several fields, with their county averages of 525 and 340 beetles per 100 interior sweeps, respectively. Undoubtedly some of the highest numbers I’ve seen in this survey.

Overall, grape colaspis numbers were higher in several districts. This follows earlier reports during the growing season of grape colaspis feeding in soybeans. Unfortunately, there is no direct correlation between grape colaspis presence in soybeans and potential for larval injury in corn the following year. Numbers continue to be variable for this insect, but were high in the east southeast counties and should bear watching in 2018.

Stink bug injury in soybeans continues to make news in the southern states. We saw little damage caused by stink bugs in this survey, though numbers were slightly higher than past years. We continue to monitor for potential spread of not only the southern species like red banded and redshouldered stink bugs, but also the spread of brown marmorated stink bug as it gets its foothold here in Illinois.

Funding for survey activities was provided by the USDA National Institute of Food and Agriculture. This survey would not be possible without the hard work and contributions of many people. I would like to thank Illinois Cooperative Agriculture Pest Survey Program interns Evan Cropek, Ryan Pavolka, Emma Sementi, Jacob Styan and Hannah Hires as well as Department of Crop Science interns Lacie Butler, Kaela Miller, and Matt Mote.


Join us for the Ewing Agronomy Field Day on Thursday, July 27, 2017

The University of Illinois Extension will host the Ewing Demonstration Center Agronomy Field Day on Thursday, July 27, 2017 at 9 a.m.  Every growing season presents challenges to production, and this year is no exception!  We are happy to host this summer field day to share with local growers current, ongoing agronomy research in southern Illinois, including cover crop trials on corn and soybeans, nitrogen management in corn, weed management in soybean, and our continuous no-till field, now in its 49th year of continuous no-till production.

 

The topics to be discussed at Field Day include:

 

Managing Nitrogen for Corn & 2017 Growing Season Overview

  • Emerson Nafziger, Extension Crop Specialist, University of Illinois

Management Strategies for PPO-resistance

  • Karla Gage, Assistant Professor—Weed Science, Southern Illinois University

Southern Rust Management in Corn

  • Talon Becker, Extension Educator, University of Illinois

Insect Headlines in 2017

  • Kelly Estes, State Survey Coordinator, Illinois Cooperative Agriculture Pest Survey Program

Cover Crops:  The Good, The Bad, and The Practical

  • Nathan Johanning, Extension Educator, University of Illinois

 

The field day is free and open to anyone interested, and lunch will be provided.  Certified Crop Advisor CEUs will also be offered.  The Ewing Demonstration Center is about 20 minutes south of Mt. Vernon located at 16132 N. Ewing Rd; Ewing, IL 62836, on the north edge of the village of Ewing, north of the Ewing Grade School on north Ewing Road.  Watch for signs.  To help us provide adequate lunch and materials, please RSVP to the University of Illinois Extension Office in Franklin County at 618-439-3178 by Monday, July 24.  For additional information on the field day, contact Marc Lamczyk at the number above or lamczyk@illinois.edu.


Insect Briefs – June 30

Japanese Beetles

Japanese beetles are back. Reports statewide indicate Japanese beetles are here (and in some locations, in very high numbers.) With corn starting to tassel and getting close to tassel, it’s important to remember, even though densities may appear to be extremely high, the average density of beetles across the field may be below levels of economic concern. An insecticidal treatment should be considered during silking if:

  • There are 3 or more beetles per ear,
  • Silks have been clipped to less than ½ inch, AND
  • Pollination is less than 50% complete.

Also remember, that there are usually clusters of Japanese beetles near field edges and if those are the only locations sampled, it will skew the numbers.

1 2

After with reports of thistle caterpillar in soybeans the past two weeks, the concern now seems to be focused on other defoliating pests like Japanese beetles.  It’s important to scout flowering soybean fields for the presence of Japanese beetles. Insecticidal treatments should be considered when defoliation reaches 30% before bloom and 20% between bloom and pod fill.

3

 

Grape Colaspis

Another pest starting to make a stir is grape Colaspis. Grape Colaspis has been a sporadic pest in Illinois. We often focus on the injury caused by grape colaspis larvae in corn. The larvae feed on root hairs and eat narrow strips from the roots. We did see quite a few adults in our 2016 statewide survey and there are some early indications that high numbers have returned to some areas this year. Foliage feeding by adults is usually insignificant but scouting will be important in areas where there are several defoliators at work.

4

Western Corn Rootworm

Western corn rootworm emergence has begun.  Emergence is still in its early stages, but as we move into the July 4th holiday, reports will be more frequent.

5

 

Corn Earworm

Corn earworm flights have been steady for 2 weeks with several locations peaking 6/15-6/20. Moths will lay eggs in the evening and with hatch in 3-4 days at 77F. Larvae feed on whorl stage corn and other host plants for a period of 3 to 4 weeks before burrowing into the soil to pupate. We expect a second generation of larvae and moths to peak in late summer.

 

European Corn Borer

Corn borer flights have been very low, but that doesn’t mean ECB isn’t present. Be sure to scout for corn borer feeding on conventional corn.

 

Fall Armyworm

Flights of fall armyworm have also been low, but consistent. There is a good chance we may still see these numbers pick up. Fall armyworm will feed during the day and night unlike the night-feeding armyworm. Early symptoms may be similar to corn borer feeding (small holes and window-pane feeding in the leaves.) As larvae get larger, they will consume more leaf tissue before moving to the ear as plants begin to tassel.

Western Bean Cutworm

Western bean cutworm trapping is underway. Numbers have been very low with only a few locations reporting a couple of moths. Purdue is reporting very large numbers the first week of trapping with the peak expected in 2-3 weeks. Wisconsin has reported WBC emergence. High risk areas include those with high moth flights and WBC history and sandy soils. We encourage scouting during the growing season as evidence at harvest does not necessarily confirm WBC presence. The latest Purdue Pest & Crop Newsletter has a fantastic article with WBC information and a video for scouting.

 

“Scouting should begin once moths are being captured nightly. In five different areas of a field, inspect 20 consecutive plants for egg masses which are laid on the upper surface of the top leaves of corn and/or larvae that may have hatched and crawled to the whorl and begun to feed. Usually the newest, vertical leaf is the best place to look for egg masses. Young larvae need pollen to survive, and female moths are most attracted to cornfields that are just about to pollinate. Moths will lay eggs on whorl stage corn when pre-tassel/pollinating corn is not available. Larvae may initially be found in leaf axils, feeding on pollen that has accumulated there. Later damage from larvae, as they feed deep in the whorl (attacking the tassel to get at pollen), will resemble corn borer or fall armyworm damage. Initially the damage will be subtle and not economically important (or even noticeable). Later stage larvae enter the ear and feed on corn kernels and can cause economic damage, and also can exacerbate ear rots, including Gibberella ear rot.”

6

 

 

Brown Marmorated Stink Bug

We continue to monitor the spread of brown marmorated stink bug in Illinois. Populations continue to grow. Most issues stem around it being a nuisance pest in homes, though we expect to see injury in agricultural and specialty crops in the near future. While we will be including BMSB in our summer surveys, I did receive my first garden report this week. Gardeners in areas with high populations should keep an eye on home gardens.

20170630_121655

Spotted Wing Drosophila

Spotted wing drosophila has become a serious pest for both specialty crop growers as well as home gardeners. This invasive fruit fly will insert eggs into healthy fruit, leading to the immature stages (maggots) that feed on the fruit flesh causing decay and reduction of quality. Often times, there is no outward indication of an infestation. While populations are low in the spring, they will gradually increase throughout the summer and later season fruit tend to have more damage. In our 2017 orchard survey, SWD has been confirmed in Pope, Champaign, and DeKalb counties in the last two weeks.

 

5444194-SMPT DrosophilasuzukiiphotoMcEvey

 

 

 


Impressive Moth Flights across Midwest

Impressive moth flights have not only kept the Illinois insect monitoring network cooperators busy, but neighboring states are reporting lots of black cutworm and true armyworm moth activity as well. The current forecast and planting progress has raised questions about the potential for these pests in the coming weeks.

With the assistance of University of Illinois Extension educators, producers and industry volunteers, nearly 60 trap sites have been established across Illinois. Captures of both black cutworm and true armyworm have been common across the state. Several counties have reported significant flights (nine or more moths caught over a 2-day period). In fact, several counties have repeated significant flights.

BCW Apr28

Illinois black cutworm projected potential cutting dates based on degree day accumulations.

 

 

As shared in previous Bulletin articles, more complete information about the biology, life cycle, and management of black cutworms, a fact sheet is available from the Department of Crop Sciences, UIUC. Provided below is a brief overview of some key life cycle and management facts concerning black cutworms.

  • Black cutworm moths are strong migratory insects with northward flights commonly observed from Gulf States into the Midwest from March through May.
  • Moths are attracted to fields heavily infested with weeds such as chickweed, shepherd’s purse, peppergrass, and yellow rocket.
  • Late tillage and planting tends to increase the susceptibility of fields to black cutworm infestations.
  • Cutting of corn plants begins when larvae reach the 4th instar — with a single cutworm cutting an average of 3 to 4 plants during its larval development.
  • Cutting tends to occur most often during nights or on dark overcast days.
  • Fields at greatest risk to cutting and economic damage are in the 1-to-4 leaf stage of plant development.
  • An early warning sign of potential economic damage includes small pinhole feeding injury in leaves (caused by the first 3 instars).
  • Producers are encouraged to look for early signs of leaf feeding as a potential indicator of cutting, rather than waiting for cutting to take place.
  • Don’t assume that all Bt hybrids offer the same level of cutworm protection. Plants in the 1- to 4-leaf stage are most susceptible to cutting.
  • Cutting of plants earlier than these projected cutting dates is possible — localized intense flights may have occurred and were not picked up by our volunteers.
  • A nominal threshold of 3% cutting of plants has traditionally been used as a point at which growers should consider a rescue treatment.
  • Not all Bt hybrids offer adequate protection against black cutworm damage. Growers should consult the Handy Bt trait table prepared by Dr. Chris DiFonzo at Michigan State University to determine the level of protection provided by their chosen Bt hybrid.

 

Switching our focus to true armyworm, this insect has also been very active this spring. Illinois has seen steady flights across the state with numbers slowing down only within the last week. Christian Krupke, Purdue, summarized the potential threat very well in a recent article. Remember, true armyworms prefer to lay eggs in grass covered areas. Wheat as well as corn planted into cover crops will be a prime target. The Handy Bt trait table above is also a great reference for hybrids that may offer some protection, but once again, don’t assume it’s 100% full-proof. With significant infestations, some damage may be observed before the Bt-proteins will suppress the feeding.

The take-home message today? Be vigilant with your fields this spring. The mild winter and warm spring certainly got things rolling. This upcoming cool and wet period may slow things down, but both black cutworm and true armyworm moths have been abundant up until this point (and they pick back up again). Please feel free to share updates from the field by email (kcook8@illinois.edu) or twitter (https://twitter.com/ILPestSurvey).

 

 

 

 


Cooperators Sought for Insect Trapping Network

Despite the snow falling outside of my window this morning, plans continue for the upcoming survey season. Mother Nature has hinted at spring with temperatures in the 70’s just last week and its time to start thinking about spring insect trapping.

We are starting to look for cooperators that are willing to place and monitor traps for black cutworm and true armyworm this spring and European corn borer, corn earworm, fall armyworm, and western bean cutworm this summer. We provide traps and lures. We ask cooperators to place and check traps several times a week, reporting trap catches to our site.

We will also be looking for cooperators to participate in our summer field surveys as well. This survey is done entirely by the Illinois Cooperative Agricultural Pest Survey Program. Each year, we have conducted a corn and soybean survey, but will also be adding an invasive species component this year. As part of our CAPS program, there are several invasive corn and soybean pests that are a threat. Included in that list are the old world bollworm, Egyptian cottonworm, , cucurbit beetle, brown marmorated stink bug, and kudzu bug in addition to western corn rootworm, soybean defoliators, and other pests. Tar spot of corn and bacterial leaf streak of corn will also be surveyed for.

If you are interested in participating in either of these programs, please use the link below.

https://www.surveymonkey.com/r/C6Q9JGM


Extension Bi-State Crops Conferences in and near Western Illinois

Newer and longer-term partnerships between personnel in Illinois and personnel in Missouri and Iowa have resulted in several bi-state crops conferences to be held during January 2017 in Western Illinois or Eastern Iowa.

 

Friday, January 6, 2017: Bi-State Crop Advantage Conference, Burlington, IA, 8:30 AM – 4:00 PM

Location: Comfort Suites, 1708 Stonegate Center Drive, Burlington, IA.

Hosts: Iowa State University and University of Illinois Extension

More Information: Click here to access the flier.

Online Registration: Click here to register

 

Friday, January 27, 2017: Bi-State Crop Advantage Conference, Davenport, IA, 8:30 AM – 4:00 PM

Location: Rhythm City Casino Resort, 7077 Elmore Ave., Davenport, IA

Hosts: Iowa State University and University of Illinois Extension

More Information: Click here to access the flier.

Online Registration: Click here to register.

 

Friday, January 27, 2017: Western Illinois-Northeastern Missouri No-till Crop Management Conference, Quincy, IL, 8:45 AM – 2:00 PM

Location: John Wood Community College, 1301 S. 48th St., Quincy, IL

Hosts: University of Illinois and University of Missouri Extension, Illinois and Missouri NRCS

More Information: Click here to access the flier.

Online Registration: Click here to register.


A Mixed Bag of Insect Densities in 2016 Corn and Soybean Surveys

Once again, statewide surveys of insects in corn and soybean fields were conducted during the summer of 2016.  A total of 33 counties were surveyed this year. The surveys were performed during the first week of August by sampling five corn and five soybean fields per county. For the past several years (2011, 2013–2016), surveys in corn and soybean fields have been conducted with the goal of estimating densities of common insect pests. Densities are reported for the various USDA crop reporting districts of Illinois to highlight portions of the state where the risk of economic insect damage is greatest. The estimates provided in this article should not be considered a substitute for scouting individual fields and making informed pest management decisions—even areas of the state that appear to be at low risk could have contained fields with high densities of a given insect pest.

Western corn rootworm beetles were sampled in cornfields by counting the number of beetles on 20 consecutive plants beyond the end rows of a given field—a beetle per plant average was calculated for each field. Much like 2015, the number of western corn rootworm adults in corn was very low throughout the state (Table 1).

Table 1  ∙  Mean number of western corn rootworm beetles per plant in corn by crop reporting district and year
District 2011 2013 2014 2015 2016
Northwest 0.26 0.33 0.05 0.02 0.02
Northeast 0.15 0.20 0.02 0.00 0.02
West 0.01 0.10 0.01 0.01 0.00
Central 0.35 0.37 0.74 0.02 0.05
East 0.31 0.81 0.51 0.01 0.01
West-southwest 0.01 0.20 0.06 0.00 0.01
East-southeast 0.02 0.01 0.00 0.00 0.00
Southwest 0.00 0.00 0.00 0.01 0.01
Southeast 0.00 0.03 0.01 0.00 0.02
Means were determined by counting the number of beetles on 20 consecutive plants for between 15 and 50 fields per district.

 

Within an adjacent soybean field, 50 or 100 sweeps were performed at least 12 rows beyond the field edge using a 38-cm diameter sweep net. The insects collected in sweep samples were identified and counted to provide an estimate of the number of insects per 100 sweeps. Depending on the year, five or ten pairs of corn and soybean fields were sampled at random in each county visited. The number of western corn rootworm adults in soybean fields throughout the state was very low as well. The greatest number of beetles in soybeans occurred in McLean County, 8.00 beetles per 100 sweeps. All other counties sampled had fewer than 5 beetles per 100 sweeps (range of 0 to 2.4 per 100 sweeps.)

Table 2  ∙  Mean number of various insect pests per 100 sweeps in soybean by crop reporting district and year

District

Year Bean leafbeetles Japanesebeetles Western cornrootworm beetles Grasshoppers Greencloverworms Soybeanloopers

Stink bugs

Northwest 2011 0.0 31.7 0.3 0.2 0.2 0.0 0.2
2013 0.3 28.3 1.0 0.4 0.0 0.0 0.1
2014 0.3 14.5 1.0 0.7 0.9 0.2 0.5
2015 1.1 13.4 0.0 1.6 1.9 0.1 0.5
2016 1.1 21.8 0 3.2 2.0 0.0 0.8
Northeast 2011 1.4 13.0 0.3 0.1 0.1 0.0 0.1
2013 0.5 13.8 10.0 0.5 0.2 0.1 0.0
2014 0.2 18.3 3.0 0.3 0.6 0.1 0.6
2015 0.7 12.9 0.1 1.7 2.3 0.0 0.6
2016 8.3 1.3 0.0 5.9 2.9 0.0 0.0
West 2011 0.7 9.5 0.1 0.6 0.7 0.0 0.2
2013 1.0 5.0 0.4 0.3 0.3 0.0 0.2
2014 11.7 2.1 0.2 1.2 0.4 0.2 1.5
2015 1.6 17.5 0.0 2.8 1.3 0.1 0.5
2016 0.9 89.4 0.7 1.5 6.6 1.4 0.2
Central 2011 3.3 24.1 0.9 0.5 0.1 0.0 0.1
2013 0.5 0.9 6.4 0.3 0.4 0.1 0.2
2014 2.4 0.7 18.9 0.6 2.6 0.3 0.7
2015 5.8 2.7 0.2 4.0 0.5 0.0 0.7
2016 16.8 2.0 5.2 4.0 10.0 0.0 0.0
East 2011 17.0 5.3 7.0 1.1 5.4 0.0 0.3
2013 1.4 2.2 9.8 1.0 1.4 0.0 0.1
2014 1.9 0.4 10.2 0.7 3.0 0.0 0.7
2015 5.5 2.0 0.1 3.8 2.3 0.0 0.8
2016 13.4 0.8 0.13 2.3 11.3 0 0.0
West-southwest 2011 1.4 7.0 0.0 1.3 6.1 0.0 0.5
2013 1.3 2.4 1.5 0.5 1.4 0.0 0.1
2014 1.8 7.3 0.4 0.4 0.9 0.3 1.9
2015 5.4 22.2 0.0 5.8 1.5 0.1 1.7
2016 4.0 10.5 0.3 5.2 12.8 0 0.6
East-southeast 2011 4.1 2.0 0.4 1.3 23.8 0.0 0.1
2013 1.1 0.5 0.1 0.4 1.6 0.0 0.0
2014 1.7 0.4 0.0 0.5 2.7 0.0 0.7
2015 0.9 2.7 0.0 1.7 3.4 0.5 2.1
2016 0.8 2.0 0.0 2.2 7.0 0.0 0.1
Southwest 2011 2.6 2.7 0.0 1.0 4.4 0.0 0.4
2013 1.2 0.4 0.1 0.3 3.4 0.0 0.2
2014 8.4 0.2 0.0 0.6 6.1 0.1 1.3
2015 0.8 2.1 0.0 1.1 2.7 0.0 0.3
2016 1.2 12.0 0.0 4.0 13.2 0.0 0.1
Southeast 2011 1.9 2.5 0.0 0.9 9.7 0.0 0.3
2013 0.5 0.5 1.5 0.1 2.4 0.2 0.3
2014 2.4 0.8 0.1 0.4 2.2 0.2 1.2
2015 0.2 2.5 0.0 1.1 3.3 0.1 0.3
2016 1.9 7.7 0.53 1.1 6.1 0 0.6
Means were determined by counting the number of insects in a 50- or 100-sweep sample for between 15 and 50 fields per district. The stink bug species reported here are the green stink bug and the brown stink bug.

 

Increased densities of some of the defoliating insect species were observed in several districts. Samples were screened for bean leaf beetles, Japanese beetles, grasshoppers, green cloverworm, soybean loopers, and stink bugs. As with many years, Japanese beetles “hot spots” were observed around the state. The western part of the state yielded the most impressive numbers (89.4 per 100 sweep average), with 240 per 100 sweeps and 108 per 100 sweeps recorded in Pike and Warren counties, respectively.  Interestingly, we had higher numbers across the board for green cloverworm in 2016. A few counties had noticeable bean leaf beetles in the samples (Central – 16.8 bean leaf beetles per 100 sweeps and East 13.4 bean leaf beetles per 100 sweeps). No brown marmorated stink bugs were detected in any of the soybean or cornfields that were sampled, though this species has been confirmed in many Illinois counties (Figure 1).

BMSB August 2016

Funding for survey activities was provided by the USDA National Institute of Food and Agriculture and the Illinois Soybean Association. This survey would not be possible without the hard work and contributions of many people. I would like to thank Illinois Cooperative Agriculture Pest Survey Program interns Evan Cropek, Colleen Musson, Ryan Pavolka, Emma Sementi, and Jacob Styan as well as Department of Crop Science interns Lacie Butler and Sarah Luce.


Insect Briefs – Soybean Aphids, Syrphid Flies, and More

–  Russ Higgins, University of Illinois Extension reports finding a couple of soybean aphids in LaSalle County this week. This follows some earlier reports in July of soybean aphids being found in low numbers in Iowa. Despite some of the recommendations floating around, direct yield loss from soybean aphid feeding does not occur when the first (or five or ten) aphids begin feeding. Today’s soybean varieties are equipped to handle minor challenges, including a few aphids. Yield loss from soybean aphid is related to how many soybean aphids are present and for how long the aphids are present and feeding. The amount of aphid population pressure over time is calculated as aphid-days. Simply put, this is the average number of aphids on a plant multiplied by the number of days they are present. A single soybean aphid on a plant for 10 days is equal to 10 aphid-days, 200 aphids on a plant for 20 days is equal to 4,000 aphid-days, and so on. This aphid-day concept proved to be a good indicator of how soybean yield responded to aphid populations. The lowest level of aphid infestation that has been shown to cause yield loss in soybean is several thousand aphid-days.

*This excerpt was taken from a larger document co-written by many entomologists in the North Central region (see list below). To read the full article with citations, please click on the link:​ Just the facts: A review of the biology and economics behind soybean aphid insecticide recommendations.

As always, we continue to encourage growers to scout fields and utilize economic established economic thresholds.

University of Minnesota: Bruce Potter, Robert Koch & Phil Glogoza
Iowa State University: Erin Hodgson
Purdue University: Christian Krupke
Penn State University: John Tooker
Michigan State University: Chris DiFonzo
Ohio State University: Andrew Michel & Kelley Tilmon
North Dakota State University: Travis Prochaska & Janet Knodel
University of Nebraska: Robert Wright & Thomas E. Hunt
University of Wisconsin: Bryan Jensen
University of Illinois: Kelly Estes & Joseph Spencer

 

–  I’ve received a few reports of maggots in corn. I believe these insects are syrphid fly larvae. One report indicated large numbers of these larvae throughout the entire corn field. Syrphid fly larvae are actually predators of soft-bodied insects like aphids. They are not causing injury to the corn. Perhaps some of you may remember a similar story out of Indiana last year: https://www.no-tillfarmer.com/articles/4935-looping-worms-and-sweat-bees-seen-in-corn

–  Despite inconsistent moth flights, there are reports of fall armyworm and corn earworm feeding in corn.

–  We’ve had a few western bean cutworm in traps in northern Illinois. Flights generally peak in mid-July.


University of Illinois Plant Clinic: Celebrating 40 Years of Service to Illinois

Anniversary Overview of Plant Clinic: Welcome to another year of service at the Plant Clinic! Since 1976, the University of Illinois Extension Plant Clinic has served as a clearinghouse for plant problems. Housed first in the Department of Plant Pathology and now Crop Sciences, the Plant Clinic was originally developed to help County Cooperative Extension staff and campus-based Extension specialists with requests for diagnoses on a wide variety of plants. By acting as a centralized diagnostic laboratory, the Plant Clinic  serves as a source of information about plant problems in Illinois.  While our primary mission is to provide diagnostic service to Illinois,  the Clinic maintains permits to receive plant, pest, and soil samples from the continental US and territories.

For most of its existence, the Plant Clinic was open from May through October. In 2010, we began year round operation.  During the off-season diagnostic staff write grants, compile reports, write fact sheets, and present at conferences and meetings around the state to support the outreach mission.  Our Nematology diagnostic clinic staff process samples and bioassays year round. The Plant Clinic has taken a lead role in the Illinois First Detector Invasive Species Workshops which started in 2013, as a part of our NIFA CPPM-EIP grant that supports IPM and diagnostics outreach. The workshops are held every year in various locations across Illinois and educate green professionals, city and municipal employees, and concerned public about invasive plants, insects, and diseases that threaten Illinois horticulture and agriculture.

U of I Plant Clinic Diagnostic Lab

U of I Plant Clinic Diagnostic Lab

For the past several years, the Plant Clinic has processed over 4,000 plant and soil samples annually. The vast majority of the plant samples are analyzed for disease and insect problems, though plant and insect identification is also performed. The soil samples are analyzed for nematode populations, including Soybean Cyst Nematode and vermiform pathogenic nematodes. Last year a new service testing for herbicide resistance in waterhemp was offered. Protocols for molecular testing for glyphosate and PPO-inhibitor resistance were adapted from ones developed in Dr. Tranel’s laboratory at the University of Illinois, 338 fields (representing 1350 plants) were analyzed. Plants were submitted from Illinois and 4 other Midwestern states.

The Plant Clinic works with the National Plant Diagnostic Network, Illinois Department of Agriculture and the National Sentinel Plant Network to stay aware of new threats in Illinois. Last year we found several new pests in Illinois, including jumping worms (an invasive earthworm) in northern Illinois, and tar spot of corn in north/central Illinois (this disease was found in Illinois and Indiana in 2015 and was a first find in the country). The Plant Clinic also works with the Illinois Department of Agriculture and Illinois Crop Improvement Association to certify diseases present crops for export, and has a partnership with the Illinois Department of Natural Resources to monitor the health of natural areas in Illinois.

The Plant Clinic employs undergraduate and graduate students, providing them with hands-on experience working in a plant diagnostic laboratory and expanding their outreach skills. Staff write articles for various online newsletters, including the Home, Yard, and Garden Pest Newsletter (http://hyg.ipm.illinois.edu/) and The Bulletin (http://bulletin.ipm.illinois.edu/). The Plant Clinic participated in the ACES Family Academies in 2015, where youth ages 6-13 got a chance to use microscopes, inoculate plants, and wash soil to collect nematode eggs. Departmental service includes opening the laboratory for tours and hands-on activities for students, and outreach at events such as Agronomy Day held every August.

Sample Information for the 2016  Season: Plant Clinic services include plant and insect identification, diagnosis of disease, insect, weed, and chemical injury problems (chemical injury on field crops only), nematode assays, herbicide resistance testing of waterhemp to PPO and glypohsate, and help with nutrient related problems, as well as recommendations involving these diagnoses. Microscopic examinations, laboratory culturing, virus assays, qPCR, ELISA and nematode assays are some of the techniques used at the Plant Clinic. Many samples can be diagnosed within a few days. Should culturing be necessary, isolates may not be ready to make a final reading for 10-14 days. Standard nematode processing also requires 1-2 weeks depending on the procedure. Some nematode bio-assays can take up to 4 months. We send your final diagnosis and invoice to you through both the US mail and email.

Please refer to our website at http://web.extension.illinois.edu/plantclinic/ for additional details on samples, sample forms, fees, and services offered. If you have questions about what, where, when, or how to sample call us at 217-333-0519. When submitting a sample, please provide as much information as possible on the pattern of injury in the planting, the pattern on individual affected plants, and details describing how symptoms have changed over time to cause you concern. Pictures of the affected plants or areas can also be sent with the sample to give us a better idea of what is occurring in the environment.

Our fees vary depending on the procedure necessary. General diagnosis including culturing is $15, ELISA and other serological testing is $25, nematode analysis for SCN or PWN is $20, specialty nematode testing (such as corn) is $40. Call ahead for other specialty nematode testing or bio-assays. Checks should be made payable to the University of Illinois Plant Clinic. Please contact us if you are uncertain of which test is needed.

For more information about the Plant Clinic, including how to contact us and submit a sample, please see our website at: http://web.extension.illinois.edu/plantclinic/. We are celebrating 40 years of service to the state of Illinois all season long on our Facebook page (https://www.facebook.com/UofIPlantClinic/) and are looking forward to another 40 years of helping people with their plant problems!  authors Suzanne Bissonnette and Diane Plewa


Black Cutworm Activity Increasing Across Illinois

*Edited April 28 to include significant flights and projected cutting dates for Carroll, Effingham, and Ford counties.

Black cutworms have been observed in traps across the state for the past couple of weeks. Several counties have reported significant moth flights (9 or more moths over a 2-night span). We can use the date of the significant flight to predict potential cutting dates based on degree day predictions.

For more complete information about the biology, life cycle, and management of black cutworms, a fact sheet is available from the Department of Crop Sciences, UIUC. Provided below is a brief overview of some key life cycle and management facts concerning black cutworms.

  • Black cutworm moths are strong migratory insects with northward flights commonly observed from Gulf States into the Midwest from March through May.
  • Moths are attracted to fields heavily infested with weeds such as chickweed, shepherd’s purse, peppergrass, and yellow rocket.
  • Late tillage and planting tends to increase the susceptibility of fields to black cutworm infestations.
  • Cutting of corn plants begins when larvae reach the 4th instar — with a single cutworm cutting an average of 3 to 4 plants during its larval development.
  • Cutting tends to occur most often during nights or on dark overcast days.
  • Fields at greatest risk to cutting and economic damage are in the 1-to-4 leaf stage of plant development.
  • An early warning sign of potential economic damage includes small pinhole feeding injury in leaves (caused by the first 3 instars).
  • Producers are encouraged to look for early signs of leaf feeding as a potential indicator of cutting, rather than waiting for cutting to take place.
  • Don’t assume that all Bt hybrids offer the same level of cutworm protection. Plants in the 1- to 4-leaf stage are most susceptible to cutting.
  • Cutting of plants earlier than these projected cutting dates is possible — localized intense flights may have occurred and were not picked up by our volunteers.
  • A nominal threshold of 3% cutting of plants has traditionally been used as a point at which growers should consider a rescue treatment.
  • Not all Bt hybrids offer adequate protection against black cutworm damage. Growers should consult the Handy Bt trait table prepared by Dr. Chris DiFonzo at Michigan State University to determine the level of protection provided by their chosen Bt hybrid.

Weekly trap counts in their entirety can be found at the link below and are also shared weekly via Twitter (@ILPestSurvey) along with current pest alerts.

March 28- April 4

April 5 – April 11

April 12 – April 18

April 19 – April 25

 

The 2016 Illinois Pest Monitoring Network is part of the Area-wide Pest Monitoring Project that is supported by the National Institute of Food and Agriculture, U.S. Department of Agriculture, under award number 2014-70006-22557 and is made possible through a network of volunteer cooperators.

Kelly Estes, Illinois State Agricultural Survey Coordinator, Illinois Natural History Survey