Targeting Weed Seeds In-Crop: A New Weed Control Paradigm

The widespread evolution of multiple herbicide resistance in the most serious annual weeds infesting cropping fields has forced the development of alternative, non-chemical weed control strategies, especially new techniques at grain harvest, says a recent Weed Science Society Of America (WSSA) publication.

Harvest weed seed control (HWSC) systems target weed seed during commercial grain harvest operations and act to minimize fresh seed inputs to the seedbank. These systems exploit two key biological weaknesses of targeted annual weed species: seed retention at maturity and a short-lived seedbank. HWSC systems, including chaff carts, narrow windrow burning, bale direct, and the Harrington Seed Destructor, target the weed seed bearing chaff material during commercial grain harvest. The destruction of these weed seeds at or after grain harvest facilitates weed seedbank decline, and when combined with conventional herbicide use, can drive weed populations to very low levels. Very low weed populations are key to sustainability of weed control practices. Here we introduce HWSC as a new paradigm for global agriculture and discuss how these techniques have aided grain cropping and their potential utility in global agriculture.

Current Weed Control Paradigm in Global Field Crops: Target Weed Seedlings

The current dominant paradigm for weed control in field crops is PRE or early POST herbicides to remove weed seedlings in young, establishing crops. Crop yield is securedby controlling weed seedlings during this critical ‘‘weed free period’’during which crop plants are particularly vulnerable to weed competition.

However, despite herbicide use, some in-crop weeds inevitably escape herbicide control for a range of reasons (eg. adverse environmental conditions, insufficient herbicide, herbicide resistance, delayed emergence) and in the great majority of situations there is no other feasible, practicable method of controlling these surviving weeds. Hence, these weeds survive to maturity with the crop and produce significant quantities of seed which sustain or build a viable weed seedbank.

It is the ongoing, annual production of weed seeds that perpetuates and amplifies many crop-weed infestations in global field crops. Annual weed seedbank replenishment ensures that each year high weed numbers emerge and are herbicide treated, with the inevitable risk of resistance evolution. It has long been recognized that alternate weed control strategies are needed to alleviate intense herbicide selection.

Globally, there are few suitable alternatives to herbicides and even when alternatives (eg. cultivation, crop competition, delayed seeding) are considered, the focus remains on preventing weed seedlings from interfering with early crop growth. However, weed adaptations, such as seed dormancy, in response to changes in cultivation and cropping practices, have already occurred in several annual species including annual ryegrass, wild oats, brome grass and barley grass.

These evolutionary adaptations in response to a selection pressure further highlight the consequences of neglecting seed production and seedbank replenishment by weeds surviving early season control practices. Clearly, new tools are needed that complement early season weed control techniques by targeting annual weed seed production.

New Weed Control Paradigm: Harvest Weed Seed Control (HWSC)

Widespread multiple herbicide resistance in the very important weeds, annual ryegrass and wild radish, of Australian cropping has forced the development of additional weed control strategies.
Knowledge that the major proportion of an in-crop annual ryegrass population results from the previous season’s seed production led to a focus on minimizing weed seed production.

The biological attribute of seed retention at maturity in annual ryegrass, wild radish, and several other annual crop weed species, means that seeds are attached to the upright plant enabling the weed seeds to be collected (harvested) during grain crop harvest. For example, in field crops a large proportion (up to 80%) of total annual ryegrass seed production can be collected during a typical commercial grain harvest. These weed seeds enter the front of the grain harvester, are processed, and exit the grain harvester in the chaff fraction. An irony is that these ‘‘harvested’’ weed seeds are evenly redistributed across the crop field to become future weed problems.

Thus, grain crop harvest presents an opportunity to target weed seed production, thereby minimizing replenishment/increase of the weed seedbank. As outlined below, harvest weed seed control (HWSC) systems have been developed in Australia to target and destroy weed seeds during commercial grain crop harvest, minimizing weed seed inputs into the seedbank.

SOURCE: Weed Technology, 2013, Weed Science Society Of America, Michael Walsh, Peter Newman and Stephen Powles. Academic citations removed have been removed.

Go here to read the full academic review as a .pdf file.

Topics:

Leave a Reply

Crop Inputs Stories

MicronutrientsCharah Add Three Warehouses For SUL4R-PLUS Fertilizer
April 28, 2016
Charah, Inc., a total solutions company providing unparalleled service and innovation for the coal-fired power generation industry, announced today that Read More
Spenser Forgey, Yahama Fortix
FungicidesIndiana Farmer Wins Arysta LifeScience FORTIX Fungicide Sweepstakes
April 28, 2016
Arysta LifeScience North America recently presented Spenser Forgey, a grower from Young America, IN, with a new 2016 Yamaha Grizzly Read More
Corn Field
HerbicidesNew Wilbur‐Ellis Herbicide Targets Volunteer Corn
April 28, 2016
Wilbur‐Ellis Co., a recognized leader in marketing and distribution of crop protection products, as well as precision agriculture technology, has Read More
HerbicidesHELM AGRO Launches New HELM Sulfentrazone 4F Herbicide
April 26, 2016
HELM AGRO US, Inc. has announced the federal Section 3 registration of its new HELM Sulfentrazone 4F herbicide. Classified as a Read More
Trending Articles
Eric SfiligojMissing The Family Ties In Agriculture
April 25, 2016
By its nature, the agriculture market is cyclical. Up and down cycles come and go with a regular pattern. For Read More
HerbicidesHerbicide Resistance In Waterhemp Continues To Grow
April 22, 2016
Twenty-five years ago, waterhemp was virtually unknown to Illinois farmers. Today, the broadleaf weed blankets corn and soybean fields across Read More
Eric SfiligojBiotech Corn Drop More Economics Vs. Consumer Rejection
April 18, 2016
Since their introduction into the agricultural marketplace, biotech crops has steadily grown in acreage in the countries of the world Read More
Crop InputsBayer: 5 Reasons We Disagree With Maryland Neonic Ban
April 12, 2016
We’re disappointed that the Maryland legislature chose not to stand up for sound science and the rights of Maryland’s homeowners Read More
Corn
OpinionChallenging Global Economic Conditions Putting More Heat On U.S. Ag Retailers
April 7, 2016
There it is. That vague, slightly sickening feeling in the pit of my stomach. Things are getting weird out there. Read More
ScoutPro iPad
Precision AgWhat’s Trending In Soil Testing And Scouting
April 6, 2016
Keeping up on soil testing and scouting, especially following unusual weather conditions, can play a role in maximizing yields. Soil Read More
Latest News
BAICOR
CropLife 100BRANDT Acquires Utah Specialty Fertilizer Company
April 28, 2016
BRANDT, a leading agriculture retailer and manufacturer of specialty ag products, has acquired a majority interest in BAICOR, L.C. BAICOR, Read More
Soybean field
Industry NewsVerdesian Life Sciences Adds Vice President Of Business…
April 28, 2016
Verdesian Life Sciences has announced the addition of Marc Treurniet to the plant health and nutrition company’s management team. Treurniet Read More
ManagementBiotech Crops Developments and Millennials
April 28, 2016
Editors Eric Sfiligoj and Paul Schrimpf talk about the latest activities in biotech crops and a major shift in the Read More
Industry NewsNachurs-Alpine, Pathway Biologic Extend Marketing Agree…
April 28, 2016
Nachurs-Alpine Solutions (Marion, OH) and Pathway Biologic (Plant City, FL) announce an extension to their exclusive marketing agreement specific to Read More
MicronutrientsCharah Add Three Warehouses For SUL4R-PLUS Fertilizer
April 28, 2016
Charah, Inc., a total solutions company providing unparalleled service and innovation for the coal-fired power generation industry, announced today that Read More
Spenser Forgey, Yahama Fortix
FungicidesIndiana Farmer Wins Arysta LifeScience FORTIX Fungicide…
April 28, 2016
Arysta LifeScience North America recently presented Spenser Forgey, a grower from Young America, IN, with a new 2016 Yamaha Grizzly Read More
Corn Field
HerbicidesNew Wilbur‐Ellis Herbicide Targets Volunteer Corn
April 28, 2016
Wilbur‐Ellis Co., a recognized leader in marketing and distribution of crop protection products, as well as precision agriculture technology, has Read More
StewardshipNRCS To Help Farmers Measure Conservation Impacts On Wa…
April 27, 2016
The USDA has announced the availability of $2 million to help farmers install edge-of-field stations that monitor water quality as Read More
Planter in Iowa
EquipmentTop 10 Twitter Pics For #Plant16
April 27, 2016
Despite some wet weather in parts of the Midwest, growers and ag retailers are working feverishly to plant this year’s Read More
HerbicidesHELM AGRO Launches New HELM Sulfentrazone 4F Herbicide
April 26, 2016
HELM AGRO US, Inc. has announced the federal Section 3 registration of its new HELM Sulfentrazone 4F herbicide. Classified as a Read More
Valley Irrigation Valley 8000 series on corn
EquipmentValley Irrigation Receives Environmental Stewardship Ho…
April 26, 2016
Valley Irrigation has been recognized as a Groundwater Guardian Green Site by the Groundwater Foundation. The Groundwater Guardian Green Site Read More
Eric SfiligojMissing The Family Ties In Agriculture
April 25, 2016
By its nature, the agriculture market is cyclical. Up and down cycles come and go with a regular pattern. For Read More
HerbicidesHerbicide Resistance In Waterhemp Continues To Grow
April 22, 2016
Twenty-five years ago, waterhemp was virtually unknown to Illinois farmers. Today, the broadleaf weed blankets corn and soybean fields across Read More
ManagementIllinois Leads The Nation In 4R Certified Nutrient Mana…
April 22, 2016
As Illinois agriculture works to educate farmers about minimizing environmental impact and optimizing the use of ag nutrients, Illinois now leads Read More
Social media
Matt Hopkins7 Social Media Trends Shaping Ag Retail In 2016
April 22, 2016
After writing my last column on why social media is a must for ag retailers, I heard from several readers Read More
Industry NewsArysta LifeScience Adds Corey Abels To Midwest Sales Te…
April 22, 2016
Arysta LifeScience North America recently announced the addition of Corey Abels as Territory Sales Manager for the Midwest region. In Read More
Soybean Field
HerbicidesHELM AGRO US Unveils New Sheridan 25 WG Herbicide
April 22, 2016
HELM AGRO US, Inc. has announced the federal Section 3 registration of its new Sheridan 25 WG herbicide for selective Read More
ManagementCentennial’s Jim Fargo Talks Ag Retail
April 21, 2016
Special guest Jim Fargo discusses challenges facing this CropLife 100 retailer. Read More