Disease

Tar Spot and Fungicide Survey for Farmers and Crop Consultants

From Iowa State University Extension:

Planting is nearly here and folks are busy – but we are hoping you can help us with a tar spot and fungicide survey. This survey is the creative component for a Masters of Agronomy student, Kelsey Richie. She is hoping to get a better understanding of how tar spots may affect farmers’ decisions around fungicides. There are two surveys, one for farmers and one for crop specialists. If you could spare some time to complete the survey, it would be greatly appreciated.

The survey is only open until May 1st, so please give your input soon.

2023-2024 Midwest Fruit Pest Management Guide

The 2023-24 Midwest Fruit Pest Management Guide is now available.  The easiest way to get a hard copy is to order from the website https://mdc.itap.purdue.edu/item.asp?Item_Number=ID-465.  You can also download the guide for free.

This guide provides conventional pest management recommendations for commercial tree fruit, small fruit, and grape producers throughout the Midwest and surrounding states. These recommendations have been formulated to provide up-to-date information on pesticides and their application.

eFields Partnering with Growers to Evaluate Xyway™ Fungicide

By:  Sarah Noggle

Northern Corn Leaf Blight Symptoms

Northern Corn Leaf Blight Symptoms

Preventing significant yield losses from disease is likely on the forefront of growers’ minds following the 2021 growing season. A new product in our disease management toolbox is FMC’s fungicide Xyway™ LFR®. OSU Extension eFields program is partnering with growers to conduct on-farm trials evaluating the effect of an at-plant soil application of flutriafol (Xyway) on corn health and yield. Information from this trial will be used to improve corn disease management recommendations for growers throughout the state.

At each field site, an untreated control will be compared to plots treated with Xyway (applied in-furrow and/or 2×2). Additionally, growers also have the option to include a third treatment of Xyway (in-furrow/2×2) + VT/R1 Foliar Fungicide. For this study, a minimum of three replications is required, and four are preferred. Plots must also be randomized to eliminate bias due to plot order. Plots should be at least 500 feet long to ensure accurate yield monitor data.

If you are interested in hosting an on-farm trial, contact Paulding County ANR Extension Educator Sarah Noggle at 419-399-8225 or noggle.17@osu.edu or Rachel Cochran, Water Quality Extension Associate at cochran.474@osu.edu.

eFields is a program at The Ohio State University program dedicated to advancing production agriculture through field-scale research. To learn more visit digitalag.osu.edu.

Tar Spot confirmed in Paulding County

Tar Spot was confirmed in Paulding County on September 7, 2021.

This week Tar Spot was confirmed in a cornfield in Paulding County. Below is a picture of what to look for when scouting for Tar Spot.  For more information on Tar Spot please see the links:

  1. https://crop-protection-network.s3.amazonaws.com/publications/tar-spot-filename-2019-03-25-120313.pdf 
  2. https://agcrops.osu.edu/newsletter/corn-newsletter/22-2021/tar-spot-showing-early-year-note-diagnosis
  3. https://agcrops.osu.edu/newsletter/corn-newsletter/2021-30/tar-spot-more-widespread-cross-state-ohio-2021

Thanks,

Will a Second Fungicide be Worth the Cost for Tar Spot Management?

Please note: While I have not observed Tar spot in Paulding County, we have had many reports of Tar spot in Hardin and Hancock Counties, and in previous years in Fulton County. Please contact Sarah Noggle if you believe you have Tar spot.  

CPN 2018. Published August 19, 2021. DOI: doi.org/10.31274/cpn-20210820-1

By:  Darcy Telenko, Purdue University; Martin Chilvers, Michigan State University; Alison Robertson, Iowa State University; Albert Tenuta, Ontario Ministry of Agriculture, Food, and Rural Affairs; and Damon Smith, University of Wisconsin-Madison.

Tar spot has quickly become a widespread concern on corn this season (2021) across much of the upper Midwest U.S. and portions of Ontario, Canada. This is especially concerning after reasonably localized epidemics resulted in low or no yield reductions over the past two seasons. This season the tar spot fungus has infected corn plants early and is rapidly increasing in many areas of the upper Midwest corn belt. The speed at which the epidemic is now moving and the crop growth stage across much of these acres (ranging from tassel to early dough) has resulted in questions about what in-season management approaches might provide an economic benefit.

Characteristic tar spot signs on a corn leaf. Image: Darcy Telenko

When is the best time to apply a fungicide for tar spot management?

Like most of the other diseases of corn, the timing of fungicide application to hedge your bets against tar spot generally is at tasseling (VT) to the silking (R1) growth stage. Recent regional research has demonstrated that while there might be little yield benefit with an application at the V6 growth stage, a single application of fungicide at VT-R1 on average can result in as much as 7 bushels or more yield compared to not treating. This is compared to just 2-3 bushels at the V6 timing and suggests that farmers are more likely to recover their fungicide costs if applying just one application at VT-R1. In the absence of tar spot and southern rust, spraying at V6 AND VT-R1 also has not resulted in economically positive returns. This practice, on average only results in an additional 1 bushel of yield compared to one application at VT-R1. There is no considerable return on investment (ROI) with two-pass fungicide programs for many corn diseases. But what about the tar spot situation this season? What do the data say about a second fungicide application to manage tar spot if I have already sprayed at VT-R1 and the disease is continuing to increase?

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