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CONTENTS

63 ...............................................................BADGER CROP CONNECT ON-LINE, JULY 29

64 ...............................................................LODGED CORN? CAN YOU DIG IT!

65 ...............................................................WISCONSIN SOYBEAN WHITE MOLD UPDATE

66 ...............................................................CORN SILK CLIPPING INSECTS AND ECONOMIC THRESHOLDS

67 ...............................................................CORN TAR SPOT UPDATE

68 ...............................................................BUILDING KNOWLEDGE ABOUT WISCONSIN’S COVER CROPS: A FARMER-RESEARCH DATA COL-LECTION PROJECT

69 ...............................................................SOYBEAN GALL MIDGE

71 ...............................................................TWO-SPOTTED SPIDER MITES

73 ...............................................................PLANT DISEASE DIAGNOSTICS CLINIC (PDDC) UPDATES

73 ...............................................................WISCONSIN PEST BULLETIN, JULY 23

74 ...............................................................VEGETABLE CROP UPDATE NEWSLETTER

BADGER CROP CONNECT ONLINE, JULY 29

Register by 5:00 PM on July 28 : https://go.wisc.edu/s5o18f

Badger Crop Connect is a crop production webinar series developed by the University of Wisconsin-Madison Extension Crops and Soils Program for the 2020 growing season. Badger Crop Connect’s goal is to bring agronomists, crops consultants and farmers timely crop updates for Wisconsin. This bi-week-ly webinar is planned to continue through September. Webinars will have CCA CEUs available as assigned. There is 1.0 credit the area of Soil and Water Man-agement available for this webinar. Resources shared by Extension Specialists will be available from the Resources link listed below.

July 29 Agenda:

• Moving Toward Soil Health – Maximizing the Growing Season

• Cover Crops Following Short Season Crops – Common Species, Mixes andManagement Tips

• The Power of Legumes

• Small Grains for Forage and Covers, Management, Varieties and Yields

UNIVERSITY OF WISCONSIN CROP MANAGER JULY 23, 2020

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Presenters:

Jamie Patton, UW-Madison NPM, Kevin Shelly, UW-Madison NPM, Daniel Smith, UW-Madison NPM, Mike Ballweg, UW-Madison Extension – Sheboygan County

Pre-registration is required –Connection link will be sent on July 29 by 9:00 AM. Please register for this free webinar at: https://go.wisc.edu/s5o18f

Resources from the webinar will be posted to this website https://fyi.extension.wisc.edu/grain/badger-crop-connection/

LODGED CORN? CAN YOU DIG IT!BRYAN JENSEN, UW-MADISON DEPT. OF ENTOMOLOGY AND INTEGRATED PEST MANAGEMENT PROGRAM

Corn lodging may or may not have had corn rootworm damage. It is the time of year, however, when larval feeding can significantly reduce root mass. But there is only one way to tell for sure. You cannot look at the above ground symptoms and make an accurate diagnosis. You will have to dig a representa-tive sample of roots, power wash and look for feeding.

Corn rootworms go through one generation/year; however, generational time is drawn out. Currently we have young larvae, late instar larvae, pupae and emerging adults present. The damage I would expect to see in the field right now would primarily be pruning but also some scarring by early instar larvae. Root pruning should peak over the next few weeks depending on your area of the state.

Future crop management decisions will benefit from proper root evaluation. Not only on lodged corn but all corn acreage. Many times, I have seen corn fields with moderate to severe root pruning standing straight. Other times I have seen severely lodged corn without rootworm injury. Many factors can contribute to or cause lodged corn including, weather, compaction, soil type, hybrid, diseases. Jumping to conclusions and assumptions may lead to un-sound management decisions.

The best time of year to evaluate rootworm damage is now. As I mentioned larval feeding should be peaking and this is the easiest time to evaluate roots for damage. If we wait until August, there may be significant regeneration of roots which can mask feeding. August root evaluations are still possible just a little more difficult.

Healthy corn roots are white. Rootworm feeding will range from scarring caused my early instars to more severe pruning and discolored roots (picture to right). The Iowa State Nodal Injury Scale (NIS), developed by Iowa State Entomologists, is the

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industry standard for quantifying root damage and focuses on root pruning cause by late instar larvae. Pruned roots are just that. However, you will need to know the difference between rootworm feeding and “shovel blight”. Frankly, it is near impossible to dig roots without cutting some with the shovel or pull-ing out of the ground which can (?) look like rootworm damage. Roots pruned by rootworms will be discolored at the tips and that discoloration may extend back on the root. Roots injury by shovel will remain relatively healthy looking but you must wash/rate roots in a short period of time.

I would suggest using a power washer to remove all soil. Remember you are looking for roots that are pruned to at least within 1 ½ in the stalk. Sometimes, especially under heavy pressure, roots will be pruned completely back to the stalk. If all the soil is not removed, you could easily miss significant damage. More information on quantify rootworm damage using the NIS can be found in this reference publication.

Evaluating corn roots for damage has multiple benefits beyond verifying if lodged corn is caused by rootworm feeding. Those extra benefits include verifying effectiveness of your current rootworm management tactic, verifying if you have early stages of Bt resistance and, if on first-year corn, if you have any damage from rotation resistant rootworms which has been very uncommon is Wisconsin for the last decade or more.

The link below leads to a video: Bryan Jensen takes you into a corn field to show you how to dig corn roots to use for rating damage.

WISCONSIN SOYBEAN WHITE MOLD UPDATEDAMON SMITH, EXTENSION FIELD CROPS PATHOLOGIST, DEPARTMENT OF PLANT PATHOLOGY, UNIVERSITY OF WISCONSIN-MADISON

Damon Smith has posted a new item, ‘Wisconsin Soybean White Mold Up-date – July 23, 2020‘ on his blog site. He also has updates there from previous weeks.

The article shows the calculated risk of soybean white mold for select Wiscon-sin locations for non-irrigated soybeans, as determined by Sporecaster smart-phone app for July 23, 2020. This means that if soybeans are flowering and the area between rows is filled in more than 50%, risk is just moderate in most lo-cations of the state, with the exception of the far northern portions of the state

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and Door County, for the presence of apothecia and subsequent white mold development.

You may view the latest post at

https://badgercropdoc.com/2020/07/23/wisconsin-soy-bean-white-mold-update-ju-ly-23-2020/

Timing in-season fungicide sprays at the correct time during the soybean bloom period can be extremely diffi-cult. To help solve this decision-mak-ing issue, models were developed at the University of Wisconsin-Madison in conjunction with Michigan State University and Iowa State University to identify at-risk regions which have been experiencing weather favorable for the development of white mold apothecia. These models predict when apothecia will be present in the field using combinations of 30-day averages of maximum temperature, relative humidity, and wind speed. Using virtually available weather data, predictions can be made in most soybean growing regions. To facilitate precise predictions and make the model user-friendly, we use Sporecaster smartphone application for Android and iPhone.

CORN SILK CLIPPING INSECTS AND ECONOMIC THRESHOLDSBRYAN JENSEN, UW-MADISON DEPT. OF ENTOMOLOGY AND INTEGRATED PEST MANAGEMENT PROGRAM

Just a quick reminder to scout corn for silk clipping by either, or both, Japanese beetles and corn rootworm adults. Japanese Beetles (pictured) are also attract-ed to green silk and typically are found along field edges. Rootworm adults, on the other hand, are more random in their field distribution.

Silk clipping is only an economic problem during the pollination stage. Once kernels are fertilized there is no longer a concern. Fields that are most likely to suffer economic damage are the earliest and latest pollinating fields in an area. Beetles are mobile and can concentrate in these fields from all neighboring fields. Not that other fields are not susceptible, just these are most likely.

Threshold guidelines indicate it takes about 3 Japanese beetles/plant to cause economic damage. However, Japanese beetle damage is usually located along field edges so entire fields may not have to be treated.

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Northern and Western rootworm bee-tles are more likely to evenly distributed throughout the field if corn develop-ment is consistent.

On average, we anticipate it will take about 5-6 rootworm beetles per plant to cause economic loss. However, do check to make sure that silks are being clipped to with ½ of the tip of the husk (see image).

Corn rootworm are not yet laying eggs so these populations will not predict the potential for root feeding if corn is planted the following year.

CORN TAR SPOT UPDATEDAMON SMITH, EXTENSION FIELD CROPS PATHOLOGIST, DEPARTMENT OF PLANT PATHOLOGY, UNIVERSITY OF WISCONSIN-MADISON, ROGER SCHMIDT, NUTRIENT AND PEST MANAGEMENT PROGRAM, UNIVERSITY OF WISCONSIN-MADISON

Grant and Columbia counties level first-detects of tar spot in Wisconsin are now on the national tar spot map. This week we are seeing more counties be-ing added in Iowa, Illinois, Indiana, and Michigan.

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Damon Smith has posted a new item, ‘Wisconsin Corn Tar Spot Update – July 23, 2020‘. Here is a short summary.

Tassels and silks are out in the southern portion of the state. We are now in the window of opportunity for a fungicide application if you feel the risk for disease, including tar spot, is warranted. While tar spot is slow to develop, we have seen gray leaf spot (GLS) developing in the lower canopy and moving up. Do some scouting and check weather reports.

Using a screenshot from the Tar-spotter beta test smartphone app, you can see (figure 2) the present risk has declined overall for most of the state with exceptions for south-central and far Northwest Wisconsin.

You may view the latest post at

https://badgercropdoc.com/2020/07/23/wisconsin-corn-tar-spot-update-july-23-2020/

BUILDING KNOWLEDGE ABOUT WISCONSIN’S COVER CROPS: A FARMER-RESEARCH DATA COLLECTION PROJECTDANIEL H. SMITH, SOUTHWEST OUTREACH SPECIALIST, NUTRIENT AND PEST MANAGEMENT PROGRAM, UNIVERSITY OF WISCONSIN-MADISON

A group from UW-Madison is looking for some good farm data to help build better knowledge about cover crops in Wisconsin. The group would like to work with you to help advance cover cropping in Wisconsin. They have devel-oped a very simple survey and data collection protocol to improve cover crop recommendations and use in Wisconsin.

Who is collecting this data and why?

They are a group of University of Wisconsin-Madison researchers, scientists, and outreach specialists looking to improve cover crop recommendations for the state of Wisconsin. This data is needed to better understand the cov-er crops that work best in Wisconsin, along with establishment timing, and potential benefits received from these cover crops. This data will help improve cover crop data in SnapPlus (SnapPlus is a nutrient management planning software program).

Timeline

For data privacy we ask that you provide contact information via this survey.

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This survey will collect information needed and ensure your farm data is protected. In addition, to safeguard your privacy, the field data you provide will never be associated with any personal information. They will not share any contact/personal information when sharing the survey results. If interested in this project, please complete the initial survey by September 1, 2020.

Phase 1

After you have entered your data in the first survey, they will send you a link to the actual data collection survey. At that time they will provide a video detail-ing more information on competing survey.

After you complete the first survey they will email you asking for photos of the cover crop at seeding, two weeks following seeding, and four weeks follow-ing seeding. they will provide a video for more information on collecting the photos.

Phase 2

They will mail you an envelope to collect the optional biomass sample. they will provide a video for more information on collecting the biomass sample. They will share a data report with you during 2020-2021 winter.

Incentive

The project will offer $25.00 to Wisconsin producers that fill out the entire survey and provide photos of the field at seeding, two weeks following seed-ing, and four weeks following seeding. An additional $75.00 will be provided to producers collecting a biomass sample (sampling envelope and postage will be provided). Total incentive $100 for about an hour of time.

They will keep you informed on what they are learning from the data via regu-lar emails as the study progresses.

Your participation is voluntary and you can leave the project at any time. To learn about the collaborative project on cover crop research and outreach, please visit www.driftless.wisc.edu.

Questions or Comments?

Daniel H. Smith, University of Wisconsin-Madison & Extension Southwest Regional Outreach Specialist for the Nutrient and Pest Management (NPM) Program- dhsmith@wisc.edu

SOYBEAN GALL MIDGEBRYAN JENSEN, UW-MADISON DEPT. OF ENTOMOLOGY AND INTEGRATED PEST MANAGEMENT PROGRAM

This is a quick reminder to be looking and thinking about soybean gall midge (Resseliella maxima). This insect has not been found in Wisconsin, but it is the time of the growing season when symptoms will start to appear. The enclosed map will show a 5-state area of the Midwest which had detects in 2018 (red counties) and 2019 (orange counties). If the map looks a little different to you, it is. Last year it was thought soybean gall midge (SGM) was present in some isolated Minnesota counties close to our border. However, identification of

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SGM is now more precise and those specimens are now considered white mold gall midge (WGM), which is not a crop pest.

Map courtesy of Dr. Justin McMechan, Dept. of Entomology, University of Nebraska

SGM is an “edge” insect and can infest a range of soybean plants from the very early vegetative stages (V3) to the late reproductive stage. Damage usually starts at the field edge and can, over the course of the growing season, be found further into a field. The majority (if not all) the feeding damage can be found at or near the soil line. A blackened epidermis is often found at the feeding site which may also appear swollen. Often, individual plants will have brittle stems that may break at the soil line. Maggots are very small (approx. ¼ inch) may or may not be present. If present, they can range in color from clear to orange.

Plant symptoms range from asymptomatic during the early stages of infes-tation to completely dead. Plants killed by SGM may be confused with other soybean diseases. Furthermore, you may think dead plants would easily stand out. Close inspection is necessary. During low incidence, healthy plants can easily obscure dead/damaged plants.Photo courtesy of Dr. Justin McMechan, Dept. of Entomology, University of Nebraska

a) Cross sectioned stem at injury site.

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b) Early instar (clear) and late instar (orange) SGM,

c) Late season injury indicating intensity of damage

If you find SGM damage I would like to know about it. Contact your local County Extension Educator, or myself (bmjense1@wisc.edu) if you find symp-toms.

For now, please be vigilant and look for symptoms.

TWO-SPOTTED SPIDER MITESBRYAN JENSEN, UW-MADISON DEPT. OF ENTOMOLOGY AND INTEGRATED PEST MANAGEMENT PROGRAM

If hot/dry weather has you thinking about Two-Spotted Spider Mites (TSSM, picture), we are on the same page. A prolonged hot weather pat-tern is certainly beneficial to increas-ing mite populations and I would recommend devoting some time to spot-checking corn and soybean fields.

As the name implies, this pest is a mite and not an insect. Adults are minute (< .02 inch), yellow green, have eight legs, and feeding stages have dark pigmented spots on either side of their oval bodies. Immatures are smaller than the adults and have either six or eight legs. Eggs are round and also yellow green.

Spot check fields or field areas you would consider droughty. Sandy soil, sandy knolls, south facing slopes and field edges are all good starting points. Mites are hard to see. A good handlense and a white sheet of paper can help with scouting. Tap leaves over the sheet of paper to dislodge mites and examine the paper with a handlense for their presence.

TSSM damage plants by piercing cells with their mouthparts and sucking sap. Because of their size, damaging populations often go unnoticed until signif-icant yield loss has occurred. Recognizing early damage symptoms is very important. Early symptoms are often called stippling and can be described as flecking on the leaves. As populations increase, chlorosis, bronzing and ulti-mately necrosis can occur.

In soybean, treatment is recommended between crop stages R1-R5 if 15% or more of the leaf area is discolored and/or if stippled and live mites are pres-ent. For corn, control is suggested if one quarter to one-third of the foliage is injured and has live mite colonies are present. Economic injury is not expected after dent.

For control options please consult A3646 Pest Management in Wisconsin Field Crops.

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In addition to the above treatment guidelines I will off the follow suggestions for your consideration:

• Read the pesticide label thoroughly. Understand there can be a big differ-ence between suppression and control. A product that only claims mite suppression is unlikely to provide the control you need under moderate to high populations.

• Be vigilant with scouting. Control is best when treatments are applied on time. You do not want to play “catch-up” with high mite populations.

• Inspect soybean fields for presence/absence of soybean aphids. Their pres-ence may (should) influence your recommendation. If aphids are increas-ing, choose a product with both mite and aphid efficacy.

• Do not underestimate the value of beneficial insects and mites in con-trolling TSSM and soybean aphids. Many of the suggested treatments are harmful to these beneficials. Spraying too early may lead to higher mite populations and/or soybean aphid flareups.

• Insecticides do not kill eggs. Miticides (Zeal, Oberon) may have some egg activity. Recheck mite populations after the REI has elapsed. Some REI’s are long.

• PHI: know the use of the crop before considering an application in corn. PHI’s are different for each use and late applications may interfere with timing of silage harvest.

• Mite resistance is a real issue. Alternate modes of action if a second appli-cation is needed. Some labels require it.

• Watch and do not exceed seasonal use rates for each active ingredient. Remember some products are combination of active ingredients and one or both may have been used previously for other insects.

• TSSM control is difficult and mites must come in contact with the pesti-cide. Efficacy is usually better with higher GPAs.

• Pesticides registered for corn may not be registered for soybean.

• Check the entire canopy for mites.

• Webbing is a sign that high populations of mites are/were present. Verify mite presence if you see webbing.

• Heavy rains can reduce populations. However, do not assume heavy rains will reduce or control TSSM

• Look at future weather reports. Consider delaying treatment if cool/wet weather is likely.

Take your mite management decisions seriously. Casual decisions are costly and can flare populations.

By the way, I understand if hots weather has you thinking about patios, camp-ing, ball games and great sunsets.

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PLANT DISEASE DIAGNOSTICS CLINIC (PDDC) UPDATESBRIAN HUDELSON, UW-MADISON PLANT DISEASE DIAGNOSTICS CLINIC

The UW-Madison Plant Disease Diagnostics Clinic (PDDC) provides expertise in diagnosing plant diseases, and information on plant diseases and their control to agricultural and horticultural producers and businesses, as well as home gardeners, throughout the state of Wisconsin.

A subset of the diseases/disorders that have been identified at the PDDC from July 11, 2020 through July 17, 2020 is attached in a fact sheet at the end of the this newsletter. If you would like to view the entire set of plant diseases the lab identifies each week, visit the PDDC Almanac page. https://pddc.wisc.edu/wis-consin-disease-almanac-2020/

If you are interested in receiving regular email updates on the educational materials and programs provided by the PDDC, please contact Brian Hudelson at pddc@wisc.edu to have your email address added to the new clinic listserv, “UWPDDCLearn”.

The PDDC is part of the Department of Plant Pathology in the College of Agri-cultural and Life Sciences at the University of Wisconsin-Madison, as well as the University of Wisconsin-Madison Division of Extension.

WISCONSIN PEST BULLETIN, JULY 23TRACY SCHILDER, WISCONSIN DEPARTMENT OF AGRICULTURE, TRADE AND CONSUMER PROTECTION

Volume 65 Issue No. 12 of the Wisconsin Pest Bulletin is now available at:

https://datcpservices.wisconsin.gov/pb/pdf/07-23-20.pdf

This Week’s Weather & Pests

Mostly dry weather with seasonal temperatures and low- er humidity main-tained favorable conditions for summer crop development in Wisconsin. Temperatures were near normal for late July, with highs in the 70s and 80s and lows ranging from the upper 40s to upper 60s.

Aside from early-week storms, calm, comfortable conditions prevail- ed across the state. The partly sunny, drier weather facil- itated harvesting of third-crop alfalfa and winter wheat, reported as 9% complete, or eight days ahead of last year and equal to the 5-year average, at the start of the week. Corn and soy-bean development also continued to outpace last year’s rates and long-term averages, with corn silking progress advancing 24 points during the we- ek to 34% complete, and 32% of soybeans setting pods.

The latest USDA NASS report ranks 80-94% of alfalfa, corn, oats, potatoes, soybeans, and wheat in good to excellent condition, far better than last year’s ratings of 49-74%. Soil moisture levels have improved and are gen- erally adequate or surplus after the recent storms, but portions of the southeast and west-central regions have become dry and could benefit from timely rain.

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Volume 65 Issue No. 11 of the Wisconsin Pest Bulletin is available at:

http://datcpservices.wisconsin.gov/pb/pdf/07-16-20.pdf

VEGETABLE CROP UPDATE NEWSLETTERAMANDA GEVENS, ASSOCIATE PROFESSOR & EXTENSION SPECIALIST, POTATO & VEGETABLE PATHOLOGY, PLANT PATHOLOGY DEPARTMENT

In issue 16 find: Updates from field and station research on N in potatoes, and N in irrigation water. Potato and tomato late blight (DSVs and reports from US0. Potato early blight (Pdays). Cucurbit Downy mildew updates. Agenda for Langlade County Extension Field Day (Virtual – Zoom event).

https://wisconsinpotatoes.com/wp-content/uploads/2020/07/July-19-2020.pdf

Attached are two PDDC tables.Attached is the Western Bean Cutworm info and scouting ID card from NPM/IPM. As per Jensen and also the Pest Bulletin, moth emergence increaseed sharply and has peaked at most southern and central WI monitoring sites.Here is Bryan's WCM post from July 2 on the subject-- https://ipcm.wisc.edu/blog/2020/07/western-bean-cutworm-3/

UW-Madison/Extension Plant Disease Diagnostic Clinic (PDDC) Update

Brian Hudelson, Sue Lueloff and Ann Joy The PDDC is now once again accepting physical samples for diagnosis, but due to COVID-19, only with limited hours and limited sample processing capacity. Click here for the current submission policy. The PDDC is continuing to provide diagnoses through examination of digital photographs. Digital diagnoses have not traditionally been included in the Wisconsin Disease Almanac, because such diagnoses are not verified through lab testing (critical in most situations for a diagnosis to be accurate). However, in an attempt to keep clients as informed as possible, digital diagnoses will be included in the Almanac until normal PDDC operations resume. For Almanac entries below, when a digital diagnosis would normally require a lab confirmation, the disease/disorder will be labeled as “suspected”. The following diseases/disorders have been identified at the PDDC from July 18, 2020 through July 24, 2020.

PLANT/SAMPLE TYPE DISEASE/DISORDER PATHOGEN COUNTY

FIELD CROPS

Corn Fungal Leaf Spot (Suspected)

Water Stress (Suspected)

Unspecified leaf spot fungus

None

Lafayette

Lafayette

Soybean Cercospora Leaf Blight Cercospora kikuchii Jefferson

FORAGE CROPS

Alfalfa Aphanomyces Root Rot

Charcoal Rot

Fusarium Root/Crown Rot

Phytophthora Root Rot

Aphanomyces euteiches

Macrophomina phaseolina

Fusarium oxysporum

Phytophthora sp.

Sauk

Sauk

Sauk

Sauk

FRUIT CROPS

Apple (Unspecified) Cedar-Apple Rust

Fire Blight

Frogeye Leaf Spot

Nectria Canker

Russetting

Water Stress (Suspected)

Gymnosporangium juniperi-virginianae

Erwinia amylovora

Botryosphaeria obtusa

Tubercularia sp./ Nectria sp.

None

None

Lafayette

Pierce

Ozaukee

Pierce

Waushara

McHenry (IL)

Apricot Prunus Necrotic Ringspot (Suspected)

Prunus necrotic ringspot virus

Dane

Cherry Bacterial Canker (Suspected)

Pseudomonas syringae Milwaukee

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VEGETABLE CROPS

Cabbage Yellows Fusarium oxysporum Price

Cucumber Cottony Leak Pythium sp. Adams

Onion Purple Blotch

Stemphylium Leaf Blight

Alternaria porri

Stemphylium sp.

Marquette

Marquette

Parsley Root/Crown Rot (Suspected)

Unspecified root/crown rot fungus/water mold

Crawford

Pepper Bacterial Spot (Suspected) Xanthomonas sp. Dane

Potato Black Leg Dickeya dianthicola, Pectobacterium parmentieri

Waushara

Squash (Unspecified) Heat Stress (Suspected) None Waukesha

Tomato Early Blight (Suspected)

Septoria Leaf Spot (Suspected)

Verticillium Wilt (Suspected)

Alternaria solani

Septoria lycopersici

Verticillium sp.

Washington

Dane, Milwaukee, Washington

Dane

Zuchini (Unspecified) Root Rot

Virus Disease (Suspected)

Fusarium sp.

Unidentified virus

Waushara

Waushara

SPECIALTY CROPS

Hemp (Industrial) Downy Mildew (Suspected) Pseudoperonospora sp. Shawano To learn more about plant diseases and their control, as well as PDDC educational resources and activities, visit the PDDC website at pddc.wisc.edu, follow the clinic on Facebook and Twitter @UWPDDC or email pddc@wisc.edu to subscribe to the PDDC listserv “UWPDDCLearn”.

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UW-Madison/Extension Plant Disease Diagnostic Clinic (PDDC) Update

Brian Hudelson, Sue Lueloff and Ann Joy The PDDC is now once again accepting physical samples for diagnosis, but due to COVID-19, only with limited hours and limited sample processing capacity. Click here for the current submission policy. The PDDC is continuing to provide diagnoses through examination of digital photographs. Digital diagnoses have not traditionally been included in the Wisconsin Disease Almanac, because such diagnoses are not verified through lab testing (critical in most situations for a diagnosis to be accurate). However, in an attempt to keep clients as informed as possible, digital diagnoses will be included in the Almanac until normal PDDC operations resume. For Almanac entries below, when a digital diagnosis would normally require a lab confirmation, the disease/disorder will be labeled as “suspected”. The following diseases/disorders have been identified at the PDDC from July 11, 2020 through July 17, 2020.

PLANT/SAMPLE TYPE DISEASE/DISORDER PATHOGEN COUNTY

FIELD CROPS

Corn Eyespot (Suspected)

Tar Spot

Kabatiella zeae

Phyllachora maydis

Iowa

Columbia

Soybean Charcoal Rot

Fusarium Root Rot And Wilt

Herbicide Damage

Phytophthora Root and Stem Rot

Fusarium Root Rot

Macrophomina phaseolina

Fusarium oxysporum

None

Phytophthora sp.

Fusarium graminearum

Dodge

Dane

Grant

Dane

Dodge

FORAGE CROPS

Alfalfa Aphanomyces Root Rot

Rhizoctonia Root Rot

Aphanomyces euteiches

Rhizoctonia sp.

Green

Green

Forage Grasses (Miscellaneous)

Ergot

Smut (Suspected)

Claviceps purpurea

Unspecified smut fungi

Winnebago

Winnebago

FRUIT CROPS

Apple ('Porter's Perfection')

Hardiness Issues (Suspected)

Root Rot

None

Fusarium sp., Rhizoctonia sp.

Waupaca

Waupaca

Apple (Unspecified) Apple Scab (Suspected)

Fertility Issues (Suspected)

Frogeye Leaf Spot (Suspected)

Venturia inaequalis

None

Botryosphaera obtusa

St. Croix

St. Croix

St. Croix

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FRUIT CROPS (Continued)

Apple (Unspecified) Gymnosporangium Rust

Honeycrisp Leaf Chlorosis

Gymnosporangium sp.

None

St. Croix

St. Croix

Apricot (Chinese) Hardiness Issues (Suspected)

Root Rot

None

Fusarium sp.

Waukesha

Waukesha

Cherry Brown Rot

Cherry Leaf Spot (Suspected)

Monilinia fructicola

Blumeriella jaapii

Winnebago

Rock

Gooseberry Gloeosporidiella Leaf Spot Gloeosporidiella sp. Lafayette

Grape Black Rot

Downy Mildew

Guignardia bidwellii

Plasmopara viticola

Sheboygan

Sheboygan

Peach Fertility Issues (Suspected) None Vernon

Raspberry Anthracnose (Suspected)

Fertility Issues (Suspected)

Raspberry Leaf Spot (Suspected)

Virus Disease (Suspected)

Sphaceloma necator

None

Cylindrosporium rubi

Unspecified virus

Brown

Dane

Brown

Dane

VEGETABLE CROPS

Beet Root Rot (Suspected) Unspecified root rot fungus/water mold

Taylor

Cucumber Angular Leaf Spot (Suspected)

Fertilizer Burn (Suspected)

Rubbing Damage (Suspected)

Pseudomonas syringae pv. lachrymans

None

None

Dane, Green, Vernon

Vernon

Dane, Green

Horseradish (Unspecified)

Root Rot

Yellows

Phytophthora sp., Rhizoctonia sp., Fusarium sp.

Fusarium oxysporum

Eau Claire

Eau Claire

Pepper (Unspecified) Bacterial Spot (Suspected)

Blossom End Rot

Xanthomonas sp.

None

Milwaukee

Dodge

Pumpkin Angular Leaf Spot (Suspected)

Pseudomonas syringae pv. lachrymans

Milwaukee

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VEGETABLE CROPS

(Continued)

Snapbean Cucumber Mosaic

Herbicide Damage (Suspected)

Tobacco Mosaic

Cucumber mosaic virus

None

Tobacco mosaic virus

Iowa

Brown, Walworth

Iowa

Tomato Crown Gall Agrobacterium tumefaciens

Dane

Vegetables (Miscellaneous)

Herbicide Damage (Suspected)

None Vernon

SPECIALTY CROPS

Hop Phyllosticta Leaf Spot/Blight

Phyllosticta sp. Dodge

To learn more about plant diseases and their control, as well as PDDC educational resources and activities, visit the PDDC website at pddc.wisc.edu, follow the clinic on Facebook and Twitter @UWPDDC or email pddc@wisc.edu to subscribe to the PDDC listserv “UWPDDCLearn”.

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Western Bean Cutworm (WBC)

Adults are a night flying moth with a 1½ inch wingspan. The primary identifying characteristic is a white line on the leading edge of the forewing.

Larvae are dark colored at first hatch. Mature larvae have a tan head and body with two very short stripes (black rectangles) immediately behind the head.

Eggs are laid on the upper leaf surface near the tassel, in clusters and are bullet shaped. When first laid, eggs are white and transition to dark purple prior to hatch.

is a relatively new insect pest on Wisconsin field corn. Most common in sandy fields, larvae feed on corn kernels, which can lead to direct yield loss and possible accumulation of mycotoxins. There is one generation per year.

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white line on leading edge of forewing

two very short stripes (black rectangles) immediately behind head

9 Subscribe to the Wisconsin Pest Bulletin for current degree day (DD) accumulations and field reports: http://datcpservices.wisconsin.gov/pb/subscribe.jsp

9 Initiate egg scouting prior to tassel (~1,350 DD)

9 Scout for egg masses on the upper leaf surface; look for the shadow of the egg mass as you walk fields; infestations are usually patchy

9 Count egg masses (or small larvae) on 20 consecutive plants in 5 different areas of the field; calculate the % of plants with infestations for each area

9 Continue scouting until egg laying has slowed down

� Economic threshold: 5% of plants with egg masses (or small larvae); accumulate egg mass totals over two scouting periods

� Larvae move quickly to the ear after hatching

� Larvae in the ear are not susceptible to foliar insecticides

� Transgenic corn: Only bio-engineered corn with the Vip3A trait controls Western bean cutworm

SCOUTING MANAGEMENT

Bryan Jensen, Department of Entomology, Integrated Pest Management (IPM) Program, University of

Wisconsin-Madison, Division of ExtensionPhoto credits: Western bean cutworm adult and larvae, Adam Sisson, Iowa State University; Western bean cutworm egg mass,

Frank Peairs, Colorado State University; Bugwood.org

This card is available at ipcm.wisc.edu

This work is supported by the Crop Protection and Pest Management Program from the USDA National Institute of Food and Agriculture. June 2019