Agent Orange in Vietnam

My friend Dr. Ken Olsen has released his study of Agent Orange Residues in Vietnam.  This is a followup to his studies of tunnels in Vietnam.  Agent Orange is made up of 2-4D and 2-4-5T.  Neither chemical is persistent in the environment, but the mixture sprayed in Vietnam did not have toxic dioxin removed.  He has found that the dioxin is still persisting in the environment and in places around some of the airports, the dioxin is still found in very high levels.  I wrote a term paper on Agent Orange for my Weeds Class at U of I, so I am very familiar with the issue. 

Weed Control - Time of Day

It pays to follow the directions to get good weed control. The plots below show where herbicide was applied at sunrise, noon, and after sunset.  the result is obvious in the pictures.  The best time to apply is when the weeds are growing in that 10 AM to 2 PM window.  Click to enlarge.

Sunrise

Solar Noon

Sunset

Butterweed Doing Well

Looking North toward Butler T, yellow is butterweed and brown is some sort of dock.  Most corn is planted, but some fields waiting for soybeans area mess.  Still not much field work going today.

How Important is Weed Control

Kansas State University completed a 7 year study on weed control.  They found that yields were reduced by 50% if weeds are left uncontrolled.  The study published in No-Till Farmer says the annual cost of uncontrolled weeds is 43 Billion Dollars.  Weed control is needed even in organic situations.  Organic farmers use different techniques.

Control Marestail

Marestail has gone from a nuisance weed to a serious problem because of herbicide resistance.  University of Tennessee has some suggestions for control in soybeans.  

Controling Palmer Amaranth

Weed control is more critical than ever.  Many weeds are resistant to multiple herbicides.  Aaron Hagar says that the cleanest fields are those where people use multiple modes of action.  Palmer Amaranth, AKA Palmer Pigweed is one of the toughest to control.  Mississippi agronomist Phillip McKibben has a 5 step approach for controlling Palmer Pigweed.

Controlling Marestail in Soybeans.

Marestail control has gone from a minor annoyance to a must do.  You can get resistant seeds carried in the wind even if you have never used roundup.  No-Till Farmer offers good Advise on Controlling Marestail.

Marestail 

Weed Control Time

I am surprised when I work in fields where no soil applied residual herbicide  has been used.  Whether you are following up with a post application or trying to kill weeds for the first time this season, now is the time to keep track of what needs sprayed and when.  I know you may want to try to kill everything at once, but that idea may not be appropriate.  Keep in mind that the best time to kill the weeds is when they are 4 inches tall or less.

2015 Cost Control

I have written previously about controlling costs.  Looking at machinery costs and reducing rents are likely to be most helpful.  I suspect those decisions are made.

One thing that can still be corrected is weed control.  My advice would be to make sure that weeds are killed no matter the cost of getting it done.  With herbicide resistance and naturally aggressive weeds invading, weed control is of the utmost importance. You will pay for neglecting weed control for many years to come.

Prairie Farmer says don't skimp on tough weeds.  The article is well written, so check it out.  A comprehensive approach with multiple modes of action will be most effective.  If you do your own spraying, learn to look at herbicide group numbers and make sure yo are using 3 groups.

Cover Crop Tolerance to Herbicides

Last week, I wrote about planning for cover crops now.  Herbicide damage to the cover crop is one thing to look at.  Iowa State University recently published some ratings for cover crops and herbicides.  In general, cereal rye looks to be the most tolerant and Tillage radish the most sensitive.  Click the link above to read the article in No-Till Farmer.

Sprayer Clean-up

As we move into an era when we are using multiple products with multiple modes of action for good weed control, we also need to pay attention to sprayer clean-out.  Iowa State University offers some tips for cleaning your sprayer.  Click on the link.

Control Those Weeds

I attended the U of I Corn-Soybean Classic.  The classic is a road show that has been around for many years and gives a good overview of what is going on in Illinois with our major crops.

Aaron Hager's presentation may have the most widespread applicability of any of them.  Weed resistance to herbicides and how to manage it was a big part of the discussion.  His observations and recommendations are:

• Selection for resistance occurs with every application of every herbicide.
• Use a pre-plant burndown and pre-plant residual
• Scout 14 days after planting to make sure you catch weeds small.
• Scout 7 to 10 days after the application of post plant materials to make sure your herbicide worked.
• Tank mixes used, not herbicide rotation is a key to clean crops.
• Those using three herbicide modes of action stand a better chance of clean fields
• Plan on three herbicide applications

Hager also pointed out that a Weed Control Guide for Illinois is available for the first time in many years.

Good Honeysuckle Control

This honeysuckle in the edge of the woods was controlled by a mid-summer spraying of glyphosate.  The kill looks complete and there was minimal damage to surrounding vegetation.  Honeysuckle is the last green thing in the fall, so a late season spraying would be in order.  Spraying after most other stuff is dead will minimize collateral damage.

Control Weeds after Harvest

We are starting to see some open fields across the landscape.  In the past, you may have seen me question the need for fall applied herbicides to control weeds.  In recent years I have seen the light on the topic so to speak.  I am seeing generally cleaner fields in spring where fall herbicides are applied.

We do need to throw in the cover crop factor.  One thing you should consider in deciding whether or not to use cover crops it the fact they also provide weed control.  I suspect most cover crops will cost more to establish than a herbicide application, but the extra savings may tip the balance in favor of cover crops over herbicides.  Right now, the only common cover crop can still be planted effectively is cereal rye.  If you can still find seed, plant the cereal rye only where you intend to plant soybeans in the spring. 

A Farmweek News article in early September talks about using fall applied herbicide to help control resistant weeds. 

Marestail -One Tough Weed

Many weeds can be tough to control, but not many are worse than marestail.  Marestail used to be an edge of the field weed that we did not worry too much about.  Now it is not unusual to find it covering fields.  We try to control it early in pre-plant treatments, but in some fields that is not enough.  This article out of Ohio State University says that there are a few options to try for Post-emergent marestail control.

Herbicide Damage in Soybeans

Earlier in the spring I saw some early planted soybeans that just did not look healthy.  There are plenty of things that could cause problems in early planted soybeans.  Dr. Aaron Hager of University of Illinois recently posted an article on the University IPM website about herbicide damage.  He suggests reading ratings guides to determine potential for herbicide damage from various products.  Stand counts should determine the need to replant.  Different varieties have vulnerabilities as well.  All the experts are encouraging use of soil applied herbicides, but we need to do so with caution. 

Sprayer Tracks

Which sprayer travel direction causes more yield loss?

Parallel

Perpendicular

Palmer Amaranth is Here

Aaron Hager says it is not too early to scout fields for Palmer Amaranth.  Right now, you may catch the plants at an early growth stage and get them killed.  Most weed specialists are recommending eradication.  Yes that means getting out the hoes and weed hooks and getting rid of that stuff.  Aaron Hager recently posted this article for management of Palmer Amaranth. 

Residual Herbicide Working

I was happy to see that my customer had weeds dieing from his residual herbicide.  The morning glory below is on its way to dead.  He had resistance problems last year.  I am glad he s taking care of it. 

Weed Control Issues

I hope by now that everyone realizes that the days of using only one chemical to control weeds are gone.  We need to go back to the "old" days of soil applied residual herbicides for most of our control.  Roundup should be used only to clean up weeds.  Liberty resistance has not emerged, but keep in mind that Liberty is not highly rated for some of our troublesome weeds.  Also be ever vigilant for Palmer Amaranth.  Aaron Hagar offers lots of advice in this bulletin about Palmer. It is not too late to beef up your weed control.