Take Action Weed Management Webinars

By: Dr. Mark Loux, OSU

Given how messed up the whole herbicide supply and price thing is right now, it might be a good time to take advantage of free resources to improve your herbicide and weed management acumen. The USB Take Action program and university weed scientists are once again conducting a series of webinars to cover several key topics in weed management. Three webinars occur this month, and will be followed by the release of videos covering other pertinent weed-related subjects. January webinars include the following:

Value of Residuals in Herbicide-Resistant Weed Problems – Thursday, January 20, 11 am EST

Harvest Weed Seed Control Practices – Thursday, January 27, 11 am EST

Registration information can be found here.  Videos of the webinars will be made available following their broadcast.

Another great resource is the “War Against Weeds” podcast.  This podcast features guests with expertise in a variety of aspects of weed science, and discussions on integrated weed management, herbicide resistance, and other timely topics. The podcast is hosted by Sarah Lancaster, Kansas State Extension Weed Science Specialist, Mandy Bish, Extension Weed Scientist at the University of Missouri, and Joe Ikley, Extension Weed Scientist at North Dakota State.  Podcast episodes are available at https://waragainstweeds.libsyn.com/ and also on Spotify, iTunes, and Google Podcasts.

 

 

Save the Dates – Central Ohio Agronomy School

Due to COVID uncertainties the 2022 Central Ohio Agronomy School has been pushed to March. 

Monday March 7 – 6:30 – 9:00p.m.

Monday March 14 – 6:30 – 9:00p.m.

Monday March 21 – 6:30 – 9:00p.m.

Monday March 28 – 6:30 – 9:00p.m.

The School will be at the new Ramser 4-H Activity Center (on the fairgrounds)

700 Perimeter Dr.  Mount Vernon, OH  43050

More details to come

ODA Issues Quarantine for Spotted Lanternfly

Originally posted on the Buckeye Yard and Garden onLine – November 2, 2021-

Author: Amy Stone

On Thursday, October 28, 2021, the Ohio Department of Agriculture (ODA) announced a quarantine to combat the spread of the Spotted Lanternfly (SLF). This BYGL Alert includes information from their release about the new quarantine. Life Stages of the Spotted Lanternfly

SLF is now designated a destructive plant pest under Ohio law, which increases inspections and restricts movement of certain items from infested counties in Ohio and other states into non-infested Ohio counties. SLF can spread long distances quickly by people who move infested materials or those containing egg masses.

Currently, SLF is only known to be established in Jefferson and Cuyahoga counties. Individuals traveling from an SLF infested area with items including tree branches, nursery stock, firewood, logs, or other outdoor items that pose a high risk of spreading the pest, are asked to complete a self-inspection checklist on ODA’s website.

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Weather and herbicides – what to do (or not) this week

Source: Dr. Mark Loux, OSU

Current forecast is for fairly warm temperatures through late evening Tuesday evening, followed by a substantial drop in temperatures and chance of snow, followed by cold/cool temperatures through the weekend.  Primary question concerning this scenario seems to be whether it is okay to apply wheat or burndown herbicides prior to this cold snap.  Some things we know about herbicides and cold weather:

– Herbicides applied to an emerged crop just prior to or during cold weather may be more injurious compared with favorable weather conditions.  During cold weather when plants are not actively growing or growing slowly, the rate of translocation and metabolism of herbicide by the plant slows down, which can mean an accumulation of herbicide that is not being metabolized.  This can increase the risk of crop injury since metabolism of herbicide by the crop, or conversion to an inactive form, is what allows that herbicide to be safely used on the crop in the first place.  For some herbicides, there is such a large margin of safety with regard to crop safety that this is all inconsequential.  For others the margin is narrower and issues such as cold weather and sprayer overlaps are more important.  The inclusion of safeners in herbicide formulations reduces the risk of injury, usually be increasing the rate of metabolism, but may not completely solve issues that arise because of adverse weather or too high a dose.  So with regard to this week and risk of injury to wheat, we would recommend avoid applying herbicide once the cold weather starts (from Wednesday on), until warm weather resumes.

– There is less certainty in making a recommendation about whether to treat wheat on Tuesday prior to the cold weather.  We have seen instances in corn where application just prior to cold weather has resulted in greater injury.  Wheat is actively growing now under favorable weather, and should readily translocate and metabolize herbicides.  Much of this process occurs within the first few hours of application.  Temperatures do not really start to plunge until early Wednesday morning per the forecast.  While it’s somewhat of a guess, it seems that application during the first part of Tuesday would be possibly safer to the crop than later in the day.  Past experience has shown us that some wheat herbicides are just generally safer than others, so one option would be to omit the ones that have stricter growth stage guidelines or have more of a history of causing injury.  Having said this, in our research we have really not experienced injury from small grain herbicides applied per label.

– With regard to efficacy of burndown herbicides and cold weather, some of the same principles apply.  Applying herbicide from Wednesday through the weekend, when weeds are not actively growing, is not recommended due to the likely loss of activity.  Susceptible weeds metabolize herbicide slowly anyway, so the issue is a lack of translocation within the plant and the inability of herbicide to do it’s thing at the active site when plant processes are shut down.  This is the type of cold weather we referenced in the recent article about dandelions, when we have observed control of this weed to plummet.  We have also observed extremely slow control of overwintered annual weeds during cold weather.

– We would recommend going ahead with burndown herbicide applications on Tuesday, prior to the cold.  As with wheat, weeds are actively growing under favorable weather so we assume herbicides will work.  It’s still a bit of a guess, but it could be a while before field conditions and weather are suitable for application again.

– This is the type of scenario that makes us want to remind everyone again that a few dollars of herbicide in the fall can help avoid some of the nasty burndown issues that develop when spring conditions are less than optimum.  Just saying.

 

OSU Extension Virtual Programming: Week of March 8

The following virtual programs are available next week.

 

MONDAY, MARCH 8

Farm Bill Webinar: 2021 Corn and Soybean Crop Insurance Considerations

10:00 am to 12:00 pm

2021 Virtual Ohio AgritourismReady Conference

6:30 pm to 8:30 pm

 

TUESDAY, MARCH 9

Virtual Conservation Tillage Conference

8:00 am to 3:00 pm

 

WEDNESDAY, MARCH 10

Virtual Conservation Tillage Conference

8:00 am to 3:00 pm

Southern Ohio Farm Show (Virtual)

10:00 am to 11:00 am

Beef Sire Selection for the Dairy Herd (Virtual)

12:00 pm to 1:00 pm

Farm Office Live

7:00 pm to 8:30 pm

 

THURSDAY, MARCH 11

Virtual Conservation Tillage Conference

8:00 am to 3:00 pm

The Dirt on Soil Health: Investing Below the Surface (Virtual)

8:00 am to 8:30 am

 

Wood Destroying Insect Inspection Training Webinar

8:30 am to 3:30 pm

Midwest Women in Ag Community Education Series

9:00 am to 11:00 am

County Outlook Meeting (Virtual)

10:00 am to 11:30 am

East Ohio Women In Agriculture Program Series

12:00 pm to 1:00 pm

Butler Innovative Farm Forum (Virtual)

7:00 pm to 8:30 pm

 

FRIDAY, MARCH 12

Virtual Conservation Tillage Conference

8:00 am to 3:00 pm

A DAY in the WOODS (Virtual)

10:00 am to 11:30 am

Escape to the Forest Webinar

10:00 am to 12:00 pm

Farm Office Live

 

Herbicide Resistance in Ohio Waterhemp Populations

Source:  Mark Loux, OSU Extension

Waterhemp populations across the Midwest continue to develop more complex variations of herbicide resistance.  Multiple resistance to an increasing number of herbicide sites of action is the norm in many populations in states west of Ohio.  Waterhemp has on the whole developed resistance to seven sites of action, including the following:

Group 2 – ALS inhibitors – chlorimuron, imazethapyr, etc

Group 4 – Synthetic auxins – 2,4-D, dicamba, etc

Group 5 – Photosystem II inhibitors – atrazine, metribuzin, etc

Group 9 – EPSP synthase inhibitor – glyphosate

Group 14 – PPO inhibitors – fomesafen, flumioxazin, sulfentrazone, etc

Group 15 – long chain fatty acid inhibitors – metolachlor, pyroxasulfone, etc

Group 27 – HPPD inhibitors – mesotrione, isoxaflutole, topramezone, etc

Individual populations with resistance to three or more sites of action are common.  Mutations are occurring that confer resistance to several of these sites of action simultaneously, through a resistance mechanism that enhances the metabolism and inactivation of the herbicides by the plant.  For example, there appears to be a linkage in the resistance to mesotrione and atrazine, where resistance to one means it’s likely that resistance to the other occurs also.  Weed scientists have concluded that this weed is capable of developing resistance to any herbicide site of action used against it.  We aren’t actually sure what the correct recommendation is for stewardship of herbicides once a single mutation can confer resistance to multiple sites of action.  Which is the reason we stress the need to take steps in mid to late season to prevent seed from plants that survive management strategies.

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