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CONTENTS

61 ............................................................................INSECTS AND LATE PLANTINGS

63 ............................................................................TAR SPOT ON MY MIND

65 ............................................................................RMA CHANGES RULES ON FORAGE PRODUCTION ON PREVENTED PLANT ACRES

65 ............................................................................SOYBEAN AND CORN ARE CONSIDERED COVER CROP OPTIONS IN WI

66 ............................................................................CAN I USE CORN OR SOYBEANS AS A COVER CROP ON PREVENTED PLANT ACRES

68 ............................................................................A TANK FULL OF SUGAR HELPS THE PROFITS GO DOWN

69 ............................................................................INTERSEEDING COVER CROPS IN ROW-CULTIVAT-ED CORN A4175

70 ............................................................................VEGETABLE CROP UPDATES NEWSLETTER, JUNE 17, 2019

70 ............................................................................GIANT RAGWEED MANAGEMENT CHALLENGE PLOT TOUR

70 ............................................................................WISCONSIN PEST BULLETIN, JUNE 20, 2019

71 ............................................................................PLANT DISEASE DIAGNOSTIC CLINIC (PDDC) UPDATE

INSECTS AND LATE PLANTINGSBRYAN JENSEN, UW DEPARTMENT OF ENTOMOLOGY AND DIVISION OF EXTENSION

I have been getting a few questions regarding late plantings and what we might or might not see from insects. Although I will provide a few thoughts please keep in mind there are a lot of variables.

Corn

We’ve had significant flights of black cutworms in some locations this spring. So far, I haven’t heard about a lot of damage. However, late planted corn does concern me a little. In a typical year we will have several generations of black cutworms/year but only the first generation causes damage to seedling corn. This year late and very-late planted corn could be susceptible to these later generations that may have increased in numbers from the first generation.

I am not sure where armyworm damage might fit with late planted corn. Remember the adults migrate to Wisconsin each spring and we’ve had some heavy moth flights already. Late planting will not affect the overall armyworm populations. However, if there is an effect, it will be that the corn will be smaller if infested by the spring generation. It is too early to tell what, if any, effect late planting will have on the summer (2nd) generation.

European corn borers overwinter in Wisconsin and their development is driven by temperatures not planting date. Typically, first generation European corn borer doesn’t survive well on late plant-ed conventional corn. However, second generation can be more attractive to these late planting dates. European corn population have been at a historic lows so I doubt there will be any widespread damage on late planted corn. The warn-ing might be what is happening in the immediate landscape. If all corn is planted late, I think there will likely be a dilution effect on corn borer population. That is, all fields will be equally attractive to the small number of moths. However, if there are only a few late planted fields in an area, those fields could attract significant-ly more female moths to lay eggs. But again, European corn borer populations have been extremely low, I doubt there will be any widespread problems but perhaps some localized problems.

UNIVERSITY OF WISCONSIN CROP MANAGER JUNE 20, 2019

Corn rootworm larval feeding

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Corn rootworms could be an interesting insect to watch this year. Like Europe-an corn borer, their populations have been very low. However, I have seen late planted corn with significant root feeding because its root mass is smaller at the time of egg hatch. That is to suggest a similar population of rootworm lar-vae will consume a greater percentage of roots on a later planted field versus one which was planted on time.

Adult rootworm beetles are influenced by planting date. Pollen and fresh silks are an important food source for female beetles which readily move within the landscape to find the most nutritious fields. I doubt there will be significant problems if most of the corn within an area has similar planting dates. Howev-er, like European corn borer, a small number of late planted fields may attract a substantial number of beetles from nearby fields. The concern is two-fold. First, these late planted field can experience significant silk clipping which may result in poor pollination. Furthermore, if this migration occurs during the ovi-position period (mid-August to early September), significantly more eggs can be laid within that field and create a higher potential for root feeding if corn is planted the following year.

Western bean cutworms may be the wild card and their influence may depend on what is happening in the immediate landscape. Western bean cutworms overwinter and adults are starting to emerge/oviposit at approximately 1325 degree days (Base 500 F). What should you expect? Adult female moths are preferentially attracted to late vegetative corn to lay eggs. Expect a dilution factor if there are similar planting dates within an area. Expect significantly higher western bean cutworm population if there are few late planted fields during the egg laying period. It will be a timing and availability issue.

Soybean

During a typical soybean planting season only the very early planted and/or late planted fields are subject to seedcorn maggot injury. Same goes for corn, however, soybeans are more susceptible to injury. I am a little concerned that a larger portion of soybeans may have been planted during the second adult flight period. Insecticide seed treatments usually provide adequate control. However, if insecticide seed treatments were not used, there is a possibility of increased damaged in late planted fields. Especially if planting coincided with peak adult flight and/or cool weather delayed emergence. There are no effective rescue treatments for seed corn maggots. Field symptoms includes poor plant stand AND foliar symptoms including, snakeheads, scarring of the cotyledons and holes in the unifoliate leaves.

The only concern regarding Japanese beetles is to be aware of the crop stage when they do infest soybean. Remember vegetative soybeans are more resil-ient than reproductive soybeans to feeding.

Two-spotted spider mites are not directly influence by crop stage. More so by the environment. Hot/dry weather will be the driving factor for their popula-tions. Be careful what you wish for!

Soybean aphid may be an insect to be concerned about. However, a lot of time will pass before we know for sure. Late planted soybean fields typically have higher soybean aphid populations that can remain higher for a longer peri-od. Arguably, soybean aphids are one of the more difficult insects to control economically because of seasonal aphid abundance, crop stage, environment factors and/or beneficial organisms.

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My final comment is appropriate for both corn and soybean. During an unusu-al year, unusual things happen. Expect the unexpected.

TAR SPOT ON MY MINDDAMON SMITH, EXTENSION FIELD CROPS PATHOLOGIST, DEPARTMENT OF PLANT PATHOLOGY, UNIVERSITY OF WISCONSIN-MADISON

Tar spot seems to be on everyone’s mind now that corn planting is nearing the finish line. The challenging spring and wet weather has folks now focused on the various disease issues that might be in front of us if we stay in this cool and rainy pattern in Wisconsin. I addressed this concern in an article earlier this sea-son, and tar spot is certainly a disease that could be significant if the weather stays wet and cool.

As many are aware, we have worked with a group of plant pathologists in the Midwest during the winter of 2019 to develop a tar spot prediction tool. The model that runs the tool is based on data from the Arlington Agricultural Research Station located in Arlington, WI and data from a single location in Michigan. Data from several fungicide trials were used to generate probability-based predic-tion models for tar spot epidemics. The framework of the models follows that of our previous models for soybean, which run the Sporecaster application. However, the weather information and predictor variables have been changed based on our work in corn in 2018. While the preliminary smartphone application, called Tarspotter, has been programmed

it needs to be validated in replicated studies and in observational studies to determine

the accuracy. Thus, Tarspotter is not publicly available and is being tested by extension and industry colleagues during the 2019 season. With that said, I will provide an outlook based on the calculated risk and my interpretation of the risk for Wisconsin during the season.

What is the Present Risk For Tar Spot Development?

Figure 1 shows the calculated risk from Tarspotter for June 19, 2019, for vari-ous locations in Wisconsin. Figure 2 provides a zoomed view for southern and south-central Wisconsin. As you can see, the present risk is very high for tar spot development in all locations examined. This is due to the fact that the weather has been extremely cool and wet for the past 30 days across the entire state. Tar spot is favored by persistent temperatures between 60 and 70 F and high relative humidity averaging above 75% for a 30-day period. We have been right in the zone for conducive conditions for this disease.

Should I Spray Fungicide Now on My Corn in Wisconsin?

The short answer is NO! While the weather has been conducive for tar spot,

Figure 1. Tarspotter risk predictions for the state of Wisconsin on June 19, 2019.

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corn is still very young. We would not recommend spraying corn for any fo-liar disease any earlier than V6. In fact, I would urge folks to hold off as long as they can toward VT to make a fungicide application. Some things to consider in this decision to spray fungicide for tar spot at V6 would be the field history. Has tar spot ever been found in a field? If not, then there is presumed to be no local inoculum available for infection, even if conditions are conducive (remember that the disease triangle is important). In fields with no history of tar spot, scout regularly and monitor the risk maps and what we are recommending based on our observa-tions. You might be able to hold off longer on that fungicide application and get it on at VT where a return on your fungicide

investment is more likely. If you have had a history of tar spot and you know that you have a hybrid that is more susceptible and

there is a large amount of infested residue, then you should monitor this situa-tion closely. Remember that the first 4 or 5 leaves on a corn plant don’t contrib-ute to yield. In fact the corn plant will soon get rid of those leaves, as the adult leaves emerge and the stalk elongates. Thus protecting leaves prior to V6 or V8 really doesn’t make a lot of economic sense (let alone biological sense for the Midwest). If you have had a history of the disease, conditions remain condu-cive, and the crop is V6-V8 or later, a fungicide application might make sense. Weigh the economics of this application and shop around. There are many products that have demonstrated decent efficacy toward tar spot. You can find our 2018 fungicide test summaries by CLICKING HERE and scrolling down to pages 2-7.

The Summary

While weather has been conducive for tar spot over the last month, do a little homework and evaluate the likelihood that tar spot might develop early in your field. Remember, if you have no history of the disease, then the likelihood of local inoculum being present is low. Saving the fungicide application for lat-er in the season might be a better option. If you have a history and you know you have a susceptible hybrid coupled with a no-till situation, then the risk is higher and you need to evaluate the economics of doing an application of fungicide as early as V6. Remember, if you do a V6-V8 application of fungicide, conditions could stay conducive later in the season for tar spot. Those early applications will “burn out” but the time the tasseling period rolls around. So if you do put a fungicide spray on at V6, you might have to come back at VT with another application to protect plants during the reproductive phase, should we stay in favorable conditions for tar spot. Keep an eye on the weather and keep scouting!

The post Tar Spot on My Mind appeared first on Badger Crop Doc.

Figure 2. Tarspotter risk predictions for southern Wisconsin on June 19, 2019.

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RMA CHANGES RULES ON FORAGE PRODUCTION ON PREVENTED PLANT ACRESPAUL D. MITCHELL, EXTENSION STATE SPECIALIST IN CROPPING SYSTEMS AND ENVIRONMENTAL MANAGEMENT, DEPARTMENT OF AGRICULTURAL AND APPLIED ECONOMICS

On June 20, the USDA RMA announced relaxation of the rules restricting forage production on prevented plant acres: https://www.rma.usda.gov/Policy-and-Procedure/Bulletins-and-Memos/2019/MGR-19-015. Farmers now only have to wait until after September 1 and can also make silage, haylage or baylage from the cover crop planted on prevented plant acres (as well as bale hay/bedding or graze as before). Previously, farmers had to wait until after No-vember 1 and could only bale hay or graze the prevented plant acres. Farmers still cannot harvest grain or seed from cover crops planted on prevented plant acres. This change will help many WI farmers dealing with forage shortages due to low hay stocks, winter kill and the wet spring. A variety of resources are available online and from the ag media, including these for Wisconsin (https://aae.wisc.edu/pdmitchell/CropInsurance/CornSoyasCoverCrop.pdf and https://aae.wisc.edu/pdmitchell/CropInsurance/LatePreventPlant2019.pdf). As always, we strongly encourage farmers to communicate with their crop insurance agents to be sure that their specific plans for prevented plant acres are allowable, otherwise a farmer may lose part or all of their prevented plant indemnity or insurance coverage.

SOYBEAN AND CORN ARE CONSIDERED COVER CROP OPTIONS IN WIARTICLE WRITTEN BY SHAWN P. CONLEY, JOE LAUER AND PAUL MITCHELL

Today Joe Lauer and myself had the opportunity to travel to Door County and participate in an Extension meeting hosted by Annie Deutsch, Jamie Patton and Aerica Bjurstrom. We had great conversation with the group about the agronomic implications of the 2019 growing season. During this meeting we touched on the issues regarding prevent plant and what to do next. This is a obviously a complex issue but an interesting point was brought forward by Dan Muhlenbeck a crop insurance specialist… “Is soybean and/or corn con-sidered a cover crop in WI?” (I hope you all notice that in my blogs soybean always precedes corn..) Here are our thoughts.

For a crop to be considered a cover crop RMA states that “For crop insurance purposes, a cover crop is a crop generally recognized by agricultural experts as agronomically sound for the area for erosion control or other purposes relat-ed to conservation or soil improvement.” Soybean and corn both meet this requirement. However please remember that BMP’s must be followed to meet this requirement.

In a late planted, soybean cover crop situation, plant a minimum of 150,000 seeds per acre and strive to plant in narrow row spacings (<30 inches). This recommendation is intended to minimize soil erosion, maximize ground cover and weed suppression as well as provide adequate N fixation. I do however

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understand if a farm operation is limited by equipment restrictions (e.g. they only have a 30 inch row planter) I would not preclude them from being eligible to plant soybean as a cover crop. The next consideration is cost. Normally the cost of soybean seed to be used as a cover crop on a per acre basis would be cost prohibitive; however since soybean seed is usually not saved from year to year and treated seed is often devitalized it is often offered at a deep discount late in the year so shop around. Frankly with only 60% of the WI crop planted there should be some reasonably priced seed to be used as cover crops.Now lets talk about corn!

Although corn is not usually considered a cover crop due to 30-inch row spac-ing and slower early canopy growth than other crops, it is deep-rooted and by the end of the end of the growing season can produce more than 5 Tons DM/A of stover even when planted in July. Ultimately the decision to use corn as a cover crop is the cost of production. Typically, it would cost $400 to $450 per acre to establish corn. Production costs can be reduced by using seed that is not bioengineered, reducing N fertilizer to around 40 to 60 lb N/A, and using a narrower row corn planter (<30-inches), a twin-row planter, or grain drill to narrow row-spacing.

To be clear the intent of this article is to designate that soybean or corn can be considered as options for cover crops. The first thing you must do however is talk to your crop insurance agent and make no decisions without their input. Also please review this excellent article by Paul Mitchell entitled: Can I Use Corn or Soybeans as a Cover Crop on Prevented Plant Acres?

Please remember that: “Farmers taking the full prevented plant indemnity should note that they cannot harvest the cover crop for grain, seed or silage, even after November 1. If they want to harvest it, then they should declare it as a alternative crop and only collected the partial (35%) prevented plant indemnity.”

This is a dynamic discussion so please check back as text and recommenda-tions are subject to change as “to be frank” no one really has all the answers on this topic.

CAN I USE CORN OR SOYBEANS AS A COVER CROP ON PREVENTED PLANT ACRESPAUL D. MITCHELL, EXTENSION STATE SPECIALIST IN CROPPING SYSTEMS AND ENVIRONMENTAL MANAGEMENT, DEPARTMENT OF AGRICULTURAL AND APPLIED ECONOMICS

As many Wisconsin farmers are taking prevented plant payments for their in-sured corn or soybeans acres, they are asking what they can use for cover crops on these acres. Traditional cover crop seed is hard to find this year with all the prevented plant acres in the region and farmers already have corn and/or soybean seed. Thus the question: Can I use corn or soybeans as a cover crop on prevented plant acres? The short answer is yes, but only if planted sufficiently late and if the cover crop is never harvested for grain, seed or silage/green chopped, even after November 1. Note that a cover crop can be grazed, baled for hay or baled for straw/stover for bedding, including a corn or soybean corn

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crop, but only after November 1. This bulletin provides guidance to farmers, examining at three options.

First, if a farmer takes the full prevented plant indemnity, planting the same crop as a cover crop before the end of the late planting period is not allowed.

Instead, the farmer should report it as late planted with a reduced guarantee. For all but northern Wisconsin, June 25 is the end of the late planting period for corn grain, June 30 for corn silage. For soybeans, the late planting period ends on July 5 for the northern two-thirds of Wisconsin and on July 10

for the southern third. Therefore, after taking a full prevented plant indemnity, planting corn or soybeans as a cover crop before these dates is not allowed. These maps shows the dates for the end of the late planting periods for each Wisconsin county. If a farmer wants to plant a cover crop during this period, something other than corn and soybeans should be planted.

Second, if the goal is to harvest forage from prevented plant acres, then farm-ers should take the partial prevented plant payment (35% of the full payment) and acknowledge forage as the alternative crop. Technically farmers can take the full prevented plant indemnity and wait until after November 1 to graze the cover crop, to bale it as hay for feed or to bale it as straw/stover for bed-ding (making silage is not allowed, even after November 1). However, this is a risky practice for forage production in Wisconsin and not recommended. Rather, farmers should take the partial prevented plant payment (35% of the full payment) and acknowledge forage as the alternative crop. If farmers have questions, they should consult with local agronomic experts for recommend-ed crops for forage production as an alternative crop. Potentially, a full season corn hybrid (105-110 days) planted in early July may be a viable option for corn silage production, but it will not be insurable.

Third, the RMA does not have an official list of approved cover crops. RMA states that “For crop insurance purposes, a cover crop is a crop generally rec-ognized by agricultural experts as agronomically sound for the area for ero-sion control or other purposes related to conservation or soil improvement.” (https://www.rma.usda.gov/en/Fact-Sheets/National-Fact-Sheets/Cover-Crops-and-Crop-Insurance). Thus a local agronomic expert, such as a University of Wisconsin Extension county crops agent, could provide a letter to a farmer and crop insurance agent that corn or soybeans was an acceptable cover crop in their county. Alternatively, a University of Wisconsin Extension state agro-nomic specialist could provide publically available written guidance on how to use corn or soybeans as a cover crop on prevented plant acres in Wisconsin including recommended agronomic practices. If farmers use corn or soybeans as a cover crop, they should carefully document the destruction of the corn or soybean cover crop (e.g., with dated photographs), that it was not chopped for forage or harvested for grain or seed, and if they grazed it or baled it for hay or straw/stover, that they did not do so until after November 1, and that is it clearly for bedding. Potentially, this documentation could include a written statement from an Extension county crops agent or other third party expert witness documenting and certifying these activities and their dates.

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Finally, many farmers have been wondering about the impact of prevented plant acres on USDA support payments. The market facilitation program (MFP) has been announced for 2019, with Secretary Perdue making an official press release on June 10: link here . At this time, it seems that MFP payments will not be made for prevented plant acres (see item 4), but these interpretations can evolve, as MFP is authorized by executive order, not an existing law. Prevented plant payments do not affect Agricultural Risk Coverage (ARC) or Price Loss Coverage (PLC) payments. Lastly, how the USDA Farm Service Agency will count prevented plant acres as acres planted for determining base acres is officially unclear and has to be clarified by Congress.

A TANK FULL OF SUGAR HELPS THE PROFITS GO DOWNSHAWN P. CONLEY, SOYBEAN AND WHEAT EXTENSION SPECIALIST, DEPARTMENT OF AGRONOMY

This growing season has been what I can best describe as “Craptacular“. Farm-ers are under severe economic stress and are looking to squeeze the highest yields possible out of whatever acres they were able to get planted. Across the Midwest post emergence herbicide applications are going out and farmers are considering what else to add into the tank to “help” their crops. This year the question of sugar has resurfaced so I thought I would dust off and re-post the below article originally entitled “Do Foliar Applications of Sugar Improve Soybean Yield”.

I also wanted to link to a few other articles from colleagues at the University of Nebraska “Sugar Applications to Crops – Nebraska On-Farm Research Net-work Results” and “Research Results: Sugar Applications to Crops“. In short the University of Nebraska team did not find a consistent yield increase in corn or sorghum and averaged 0.8 bu per acre in soybean. If farmers are considering a pass for just the sugar application the average cost of ground application in $7.65 and aerial is $10.75; 2019 Iowa Farm Custom Rate Survey and the aver-age yield loss caused by sprayer wheel track damage in soybean in rows less than 20 inches is 1.9 or 1.3% with a 90 or 120 foot boom, respectively.

I also want to give credit to my colleague Chad Lee who wrote a nice article entitled “Could Sugar Help Drought Stressed Corn?” that discusses sugar rates, biological activity and actual costs of product.

I am certain this re-posted article will stir up the same severe indignation as the original, however when the local cash bids are averaging $8.42 ROI is more important than ever.

Do Foliar Applications of Sugar Improve Soybean Yield (Originally published: June 14th, 2011)

High commodity prices have led growers to consider many novel soybean inputs. One input that has garnered considerable attention is the foliar applica-tion of sugar products to increase soybean yield. The objective of this research was to evaluate soybean yield in response to various sources of foliar-applied sugar across four states in the Midwest. Field research studies were conducted at Arlington, Wisconsin; Urbana, Illinois; St. Paul, Minnesota; and West Lafay-ette, Indiana in 2010.The four sources of sugar evaluated in this study were:

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Granulated cane sugar

High fructose corn syrup

Molasses

Blackstrap molasses.

All treatments were applied at the equivalent rate of 3 lb sugar a-1 and applied at 15 to 20 gal a-1. The treatments consisted of an untreated check, all four sources of sugar applied at V4, granulated cane sugar and blackstrap molas-ses applied at R1, granulated cane sugar applied at V4 and R1, and blackstrap molasses applied at V4 and R1.

No positive or negative (phytotoxic) effects were visually observed on the soy-bean foliage at any location within 10 days following foliar applications (data not shown). Furthermore, sugar did not increase soybean yield within location (data no shown) or across locations [P= 0.60 (Figure 1)], regardless of source. While this study cannot conclusively prove foliar applications of sugar will not increase soybean yield, the authors conclude that other management strate-gies to improve soybean yield should take precedence over applying sugar.

INTERSEEDING COVER CROPS IN ROW-CULTIVATED CORN A4175DANIEL H. SMITH, NUTRIENT AND PEST MANAGEMENT PROGRAM – UNIVERSITY OF WISCONSIN-MADISON

Interseeding cover crops can be a challenge. A recent study at Arlington Agri-culture Research Station evaluated interseeding cover crop into row-cultivated corn. For more information on interseeding cover crops in row-cultivated corn, please follow this link to read the full publication detailing the study with inter-

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seeding recommendations.

View the full article at: https://learningstore.uwex.edu/Assets/pdfs/A4175.pdf

VEGETABLE CROP UPDATES NEWSLETTER, JUNE 17, 2019AMANDA GEVENS, ASSOCIATE PROFESSOR & EXTENSION SPECIALIST, POTATO & VEGETABLE PATHOLOGY, PLANT PATHOLOGY DEPARTMENT

Update 8- June 17, 2019

In this issue the UW-Madison Division of Extension Vegetable Crop Updates Newsletter #8:

• Vegetable insect pest updates

• Potato disease update with late light symptom and fungicide listing for 2019

GIANT RAGWEED MANAGEMENT CHALLENGE PLOT TOUR

In collaboration with Nick Baker (UW-Extension Agricultural Agent in Rock County, WI), we are pleased to announce our 1st WiscWeeds Giant Ragweed Management Challenge Plot Tour (June 26, 2019 at Rock County Farm, Janesville, WI)!

Giant ragweed was ranked as the 2nd most troublesome weed species in Wisconsin row crop production in our recent survey. To learn more about giant ragweed management in corn and soybean, join us for a tour of our research plots showcas-ing comparison of multiple PRE and POST-emergence herbicide pro-grams. Come prepared to gather you own data on giant ragweed control and collect good images from our studies!

Please send RSVP to Nick Arneson (see contact info in flyer).

Flyer can be found here

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WISCONSIN PEST BULLETIN, JUNE 20, 2019KRISTA HAMILTON, ENTOMOLOGIST, WISCONSIN DEPARTMENT OF AGRICULTURE, TRADE AND CONSUMER PROTECTION

Volume 64 Issue No. 08 of the Wisconsin Pest Bulletin is now available at: https://datcpservices.wisconsin.gov/pb/pdf/06-20-19.pdf

LOOKING AHEAD: True armyworm larvae appearing in cornfields

FORAGES & GRAINS: Above-threshold potato leafhopper counts noted in a few fields

CORN: Corn rootworm egg hatch underway

SOYBEAN: Soybean aphids found in Columbia and Sauk counties

FRUITS: First spotted wing drosophila flies captured this week

VEGETABLES: Squash vine borer moths likely to begin flying next week

NURSERY & FOREST: Boxwood blight and jumping worm updates

DEGREE DAYS: Growing degree day accumulations as of June 19, 2019

This post originates at the Wisconsin Pest Bulletin website

PLANT DISEASE DIAGNOSTIC CLINIC (PDDC) UPDATEBRIAN HUDELSON, SUE LUELOFF, ALEX MIKUS AND ANN JOY

The PDDC receives samples of many plant and soil samples from around the state. The following diseases/disorders have been identified at the PDDC from June 8, 2019 through June 14, 2019.

View table of diseases/disorders here: https://pddc.wisc.edu/wp-content/up-loads/sites/39/2019/06/FullTable061419.pdf