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CONTENTS

43 ......UW RESEARCH ON INDUSTRIAL HEMP TO BE HIGHLIGHTED AT AGRONOMY/SOILS FIELD DAY

44 ............................................................................... WISCONSIN WINTER WHEAT DISEASE UPDATE

44 ............................................................................................... INSECTS AFFECTING PLANT STANDS

46 .................................................................................................WHAT’S ON YOUR SEED? UPDATED!

46 ............................................. ASSESSING FLOOD DAMAGE TO SOYBEAN: COOLBEAN.INFO UPDATE

47 ...................................................................................................... SOYBEAN FLOWERING FALLACY

47 ...................................................................................... VEGETABLE CROP UPDATES NEWSLETTER

UW RESEARCH ON INDUSTRIAL HEMP TO BE HIGHLIGHTED AT AGRONOMY/SOILS FIELD DAY CARRIE LABOSKI, PROFESSOR AND EXTENSION SOIL FERTILITY/NUTRIENT MANAGEMENT SPECIALIST, UW-MADISON

The UW Departments of Agronomy and Soil Science invite you to the Arlington Agricultural Research Station on August 28th to learn the latest in agronomic research being conducted in the College of Agricultural and Life Sciences. Field tours will emphasize soil, crop, and pest management practices that promote soil health, improve farm profitability, and enhance environmental quality. There will be more presentations to see than time to see them! A lunch time presentation will focus on navigating today’s dairy industry.

A special after lunch only session will high-light UW’s inaugural research on industrial hemp. Grain and fiber plots will showcase research on organic weed management, conventional fertility, and variety trials. An update will also be provided on cannabidiol research.

Between tours you can visit with specialists from the UW Soil & Forage Analysis Lab, Nutrient & Pest Management Program, SnapPlus, and Pesticide Applicator Training.

UNIVERSITY OF WISCONSIN CROP MANAGER JUNE 6, 2019

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Posters highlighting additional research will also be displayed. Certified Crop Advisor continuing education credits are being requested.

The field day starts at 8:00, concludes at 2:45, and will be held rain or shine. The Public Events Building at the Arlington Ag Research Station is located at N695 Hopkins Rd, Arlington. Watch for signs on Hwy 51 about 5 miles south of Arlington. GPS coordinates: 43.300467, -89.345534

To help us organize a successful event, if you are considering attending please complete a RSVP at https://go.wisc.edu/n4yrl5 Sigma Alpha Agricultural Sorority will provide lunch ($5 donation).

For more details, see the attached flyer at https://ipcm.wisc.edu/download/wcm-pdf/AgronomyFieldDay2019_FINAL2.pdf

WISCONSIN WINTER WHEAT DISEASE UPDATEDAMON SMITH, EXTENSION FIELD CROPS PATHOLOGIST AND BRIAN MUELLER, ASSISTANT FIELD RESEARCHER, DEPARTMENT OF PLANT PATHOLOGY, UNIVERSITY OF WISCONSIN-MADISON

Wheat heads are close to emergence on some earlier varieties of winter wheat in southern and south-central Wisconsin. Within the next week wheat heads will be emerging and anthesis (flowering) will be starting, with later varieties to follow. Now is the time to prepare for Fusarium head blight (FHB or scab) man-agement. The Fusarium head blight Risk Model (http://www.wheatscab.psu.edu) is showing moderate to high levels of risk in the primary wheat growing region of the state over the next 72 hours (Figure 1). Pay close attention to the risk model and your local weather as we approach anthesis (flowering). I antic-ipate the risk to remain high as periods of rain and humidity persist. Fungicide products of choice to control FHB in Wisconsin include Caramba, Prosaro, and Miravis Ace. Multiple years of data in Wisconsin suggest that the best applica-tion window for any of these products begins at the start of anthesis until 5-7 days after the start of anthesis. Applying fungicide before anthesis or more than 7-10 days after anthesis will result in poor performance against vomitoxin accumulation.

For more resources, view the original posting at Badger Crop Doc: https://badgercropdoc.com/2019/06/04/wis-consin-winter-wheat-disease-update-june-4-2019/

INSECTS AFFECTING PLANT STANDSBRYAN JENSEN, UW DEPARTMENT OF ENTOMOLOGY AND DIVISION OF EXTENSION

This spring has been difficult. It never ceases to amaze me how hardy corn and soybean seed and seedlings are. Because of this prolonged cool/wet weather I am sure a lot of people will soon be in the field evaluating stands. Please, keep in mind that some insects can also affect plant populations. The longer it takes for seeds to germinate and seedlings to emerge means the greater the plant’s susceptibility to insect damage. When evaluating plant stands it will be impor-

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tant to determine if insects are at least part of the cause for poor plant stands. There are some clues you can use to verify.

Seedcorn maggot injury is usually randomly distributed in a field. Symptoms in corn and soybeans includes a range of damage that includes poor emer-gence or holes in the cotyledon(s). Dig up the seed if you have poor emer-gence. Because of their short generation time and your response time you may, or may not, find the maggot present. Finding maggots is sound seed is a good sign of seedcorn maggot feeding because saprophytic maggots (non-pest) usually don’t infest sound seed. Conversely, if the seed is rotten and mag-gots are found there is a greater likelihood that something else killed the seed. Because of the brief peak adult flight periods, you are likely to find a narrow range of planting dates that are affected by seedcorn maggot.

Similar to seedcorn maggots, wireworms will also feed on the ungerminat-ed corn seed. However, unlike seedcorn maggot, their damage is usually clumped within a field. Above ground symptoms can either be holes in the newest emerging leaves and/or wilted whorl leaves depending if the larvae are feeding at or above the growing point. Timely scouting will usually result in locating wireworm larvae near some of the damaged plants. Wireworms are hard-shelled, copper colored and have three sets of jointed legs. Don’t con-fuse wireworms with millipedes which are (usually) a non-pest. Milipedes are dark-gray and have a fringe hair-like legs the length of their body. Wireworm will move deeper within the soil profile during warmer weather and will not be easily found.

Don’t focus on a single symptom. Rather look for other clues that will verify your diagnosis. Although rescue treatments are not available, verifying their presence can explain reduced plant stands.

Seedcorn maggot injury to soybean and corn. As long as the growing point is healthy there is minimal, if any, long term damage.

Seedcorn maggot injury on soybean

Wireworm larvae Millipede

Seedcorn maggot injury on corn

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WHAT’S ON YOUR SEED? UPDATED!DAMON SMITH, EXTENSION FIELD CROPS PATHOLOGIST AND RICHARD PROOST, AGRONOMIST, UW NUTRIENT AND PEST MANAGEMENT PROGRAM

Seed treatments have been used for a num-ber of years, mostly for protection against seedling diseases. However, there are a number of new seed treatments marketed for protection against a range of pests—in-cluding seedling diseases, insects and nem-atodes—and even improving plant health. The purpose of this publication is to take some of the confusion of seed treatments away, giving you a better understanding of what is on your seed. The list covers seed treatments registered in the state of Wis-consin for use on corn/soybean/small grain/alfalfa seed. 4 pages.

https://ipcm.wisc.edu/download/pubsPM/Whats_on_your_seed_web.pdf

ASSESSING FLOOD DAMAGE TO SOYBEAN: COOLBEAN.INFO UPDATESHAWN P. CONLEY, SOYBEAN AND WHEAT EXTENSION SPECIALIST, DEPARTMENT OF AGRONOMY

Severe rainfall events and flooding over the last 6+ weeks have many of the few planted soybean fields completely saturated or underwater. As the water dissipates yield potential and replant questions will arise. Flooding can be divided into either water-logging, where only the roots are flooded, or com-plete submergence where the entire plants are under water. Water-logging is more common than complete submergence and is also less damaging. Soy-beans can generally survive for 48 to 96 hours when completely submersed. The actual time frame depends on air temperature, humidity, cloud cover, soil moisture conditions prior to flooding, and rate of soil drainage. Soybeans will survive longer when flooded under cool and cloudy conditions. Higher tem-peratures and sunshine will speed up plant respiration which depletes oxygen and increases carbon dioxide levels. If the soil was already saturated prior to flooding, soybean death will occur more quickly as slow soil drainage after flooding will prevent gas exchange between the rhizosphere and the air above the soil surface. Soybeans often do not fully recover from flooding injury.

To view the full article (updated from original post 6/1/17): https://coolbean.info/2019/06/04/assess-ing-flood-damage-soybean/

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SOYBEAN FLOWERING FALLACYSHAWN P. CONLEY, SOYBEAN AND WHEAT EXTENSION SPECIALIST, DEPARTMENT OF AGRONOMY

Summary

• There is an old rule-of-thumb that soybean does not flower until after the summer solstice — the longest day of the year occurring on June 21st in the Northern Hemisphere — yet many of us have seen soybean flower much earlier.

• Early planted soybean experience shorter days before June 21st, so floral induction and the subsequent appearance of flowers may occur ahead of the summer solstice.

• Soybean management decisions depend on proper identification of reproductive stage R1 (1st flower), which means relying on scouting to observe flowers, not calendar date.

Read the full article at: https://coolbean.info/wp-content/uploads/sites/3/2017/10/2018_Soybean_flowering_final.pdf

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

View the PDF at https://wivegdis.wiscweb.wisc.edu/wp-content/uploads/sites/210/2019/06/Update-6-June-2-2019.pdf

In the June 2, 2019 issue (Update 6):

• Vegetable insect updates

• Potato disease forecasting (P-Day and DSV) updates

• Downy mildew in hop and basil in WI

• Access to the A3422 Vegetable Production Guide