Hot, Dry Weather Make It Harder To Control Weeds

While the extended periods of hot, dry weather Ohio has experienced in recent weeks may mean that weeds aren’t growing as fast as they would in more moist conditions, the weather can still have an adverse effect on weed management for growers, an Ohio State University Extension expert said.

Not only does the extended hot, dry weather and drought-like conditions impact the germination, growth, hardiness and competitive ability of weeds, but the dry weather conditions also complicate weed control efforts, said Mark Loux, an OSU Extension weed specialist.

“The biggest thing that happens to weeds when the weather conditions continue to be hot and dry is that the weeds get tougher to control,” he said. “Under good moisture, weeds tend to be more sensitive to herbicides.

“Under extended dry conditions, weeds grow more slowly and also develop thicker cuticles on the leaf surfaces, which has the overall effect of reducing herbicide movement into and throughout the plant.”

While growers often times wonder if they should wait for rain to treat weeds with herbicides or apply treatments now, Loux said, the most important thing to consider is to make sure they select the right herbicide treatment for the weeds they are trying to control.

“Growers should go ahead and spray when the weeds are small,” he said. “With the continued forecasts for little to no rain, you’re better off at this point to just pull the trigger.

“And if you spray now and it does rain and bring on the next growth of weeds, go ahead and spray again.”

Loux said that growers who wait too long could end up losing control of the weeds they currently have and may also have to spray again for the next batch of weeds that emerge in their fields.

“And if you wait to spray and then are forced to use a more aggressive herbicide mix, it can increase the level of crop injury,” he said.

Following are some tips for growers to consider:

  • Apply herbicide when weeds are small. Large and old plants become even more difficult to control when subject to extended dry conditions. Prolonged dry conditions also suppress additional weed-seed germination, so the risk of many weeds emerging after an early post-treatment is reduced.
  • Optimize adjuvants. Labels for some POST herbicides provide suggestions for revised adjuvant rates or types under dry conditions.
  • Dry weather does not usually increase the severity of injury to the crop from herbicides, unless coupled with very hot conditions. But continued dry conditions after the crop has been injured can reduce its ability to recover from injury, or extend the time needed for recovery.
  • Applying herbicides when weeds are small minimizes the need for more aggressive herbicide mixtures.
  • If you are finding that you can’t control glyphosate-resistant marestail with glyphosate plus either Classic or FirstRate, then adding other herbicides won’t help.
  • Instead, walking the fields to remove plants by hand, or at least cutting the tops off later in the season to prevent seed production, is likely the best option.

Continuation of dry weather throughout the summer will reduce the rate of dissipation in soil of certain herbicides, possibly increasing the risk of carryover into next year’s crop.

Topics:

Leave a Reply

Herbicides Stories

Crop Protection Products in storage
Crop InputsNewsweek: World Is ‘Awash In Glyphosate’
February 11, 2016
The world is awash in glyphosate, the active ingredient in the herbicide Roundup, produced by Monsanto. It has now become Read More
Crop InputsSyngenta’s Acuron Flexi Receives EPA Approval
February 11, 2016
Growers looking to control their toughest weeds with flexibility will have access to Acuron Flexi corn herbicide from Syngenta, now Read More
Crop InputsWeed Expert: Adding A Second Herbicide Not Always Easy
February 9, 2016
In my last post, I reviewed some recent research that suggests one of the best ways to delay the evolution Read More
Crop InputsGenetic Literacy Project: Farmers Need More Herbicide Choices
February 9, 2016
There are two things that I think just about every weed scientist can agree on, writes Andrew Kniss for The Read More
Top 100 Articles
Elburn Cooperative
CropLife 100Elburn Cooperative Members Vote To Join CHS
December 28, 2015
With 81% of eligible producers voting, 94% cast an affirmative ballot for Elburn Cooperative, a diversified agricultural retailer based out Read More
West Central Cooperative, Jefferson, IA
CropLife 100Farmers Cooperative-West Central Merger Approved
December 21, 2015
The members of Farmers Cooperative Co. (FC), Ames, IA, and West Central Cooperative, Ralston, IA, have both approved the merger Read More
Wheat Growers Innovation Center, Bath, SD
CropLife 100Wheat Growers Opens Innovation Center
December 21, 2015
Wheat Growers’ commitment in providing its farmer-owners with the latest in technological advancements now has a one-of-a-kind focal point, as Read More
CropLife 100ARA Selects The Andersons As 2015 Retailer Of The Year
December 9, 2015
The Agricultural Retailers Association today named Maumee, OH-based The Andersons as its Retailer of the Year for 2015. The award Read More
CPS Washington Court House John Deere Sprayer
CropLife 100Application Equipment Report: It Is Easy Being Green For Top 100 Ag Retailers
December 5, 2015
On The Muppets television show, Kermit the Frog is famous for singing a song about the troubles he encounters in Read More
Fertilizer Bin
CropLife 100Fertilizer Sales: Another Down Year For Top 100 Ag Retailers
December 4, 2015
In pure number terms, the fertilizer category still dominates all crop inputs/services among CropLife 100 ag retailers. In 2015, for Read More
Latest News
Crop Protection Products in storage
Crop InputsNewsweek: World Is ‘Awash In Glyphosate’
February 11, 2016
The world is awash in glyphosate, the active ingredient in the herbicide Roundup, produced by Monsanto. It has now become Read More
Crop InputsEPA: Let’s Talk Imidacloprid, Bees On February 18
February 11, 2016
EPA will hold an online technical briefing on its preliminary pollinator risk assessment for imidacloprid, a neonicotinoid insecticide, on Feb. Read More
ManagementThe latest on Syngenta-ChemChina Deal
February 11, 2016
Executive Editor Paul Schrimpf invites Jackie Pucci and Dave Frabotta from sister publication AgriBusiness Global to discuss the latest developments Read More
AdjuvantsUniversity of Illinois Confirms Adjuvant’s Perfor…
February 11, 2016
An independent University of Illinois study has shown that WETCIT adjuvant, now with TransPhloem technology, provides greater herbicide uptake and Read More
Crop InputsSyngenta’s Acuron Flexi Receives EPA Approval
February 11, 2016
Growers looking to control their toughest weeds with flexibility will have access to Acuron Flexi corn herbicide from Syngenta, now Read More
EquipmentAGCO Showcases White Planters 9800VE Series Planters AT…
February 11, 2016
AGCO unveiled the new White Planters 9800VE Series planter during the 2016 National Farm Machinery Show in Louisville, KY. The Read More
EquipmentCase Unveils 2000 Series Early Riser Planter At NFMS
February 10, 2016
Case IH revealed the all-new 2000 Series Early Riser planter to media and attendees at the opening of the National Read More
Syngenta Sign
Crop InputsSyngenta: Keep Ag In Mind During Election Season
February 10, 2016
As presidential candidates stake out their 2016 election platforms and key priorities, growers and their business partners should seek opportunities Read More
Crop InputsMarrone Bio Innovations Submits New Bio-Fungicide For E…
February 9, 2016
Marrone Bio Innovations, Inc. (MBI) today announced that it has submitted a new biological fungicide (MBI-110) to EPA. The broad spectrum Read More
Crop InputsWeed Expert: Adding A Second Herbicide Not Always Easy
February 9, 2016
In my last post, I reviewed some recent research that suggests one of the best ways to delay the evolution Read More
Crop InputsGenetic Literacy Project: Farmers Need More Herbicide C…
February 9, 2016
There are two things that I think just about every weed scientist can agree on, writes Andrew Kniss for The Read More
HerbicidesWeed Expert Warns North Dakota Growers Of Coming Herbic…
February 9, 2016
Ford Baldwin painted a bleak picture of weed control at a recent workshop here exploring the future of ag production, Read More
HerbicidesWSSA Announces New, Updated Free Web Resources
February 9, 2016
Today the Weed Science Society of American (WSSA) announced that new and updated educational materials for both weed scientists and Read More
Soybean field
FungicidesFour Arysta Fungicide Formulations Given FIFRA Approval…
February 8, 2016
Arysta LifeScience North America recently announced the issuance of Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) Section 2(ee) Recommendations for Read More
FungicidesAgri-Fos Systemic Fungicide Plus Receives EPA Registrat…
February 8, 2016
Vivid Life Sciences has announced the EPA registration of Agri-Fos Systemic Fungicide Plus, a highly concentrated active ingredient phosphite fungicide, Read More
Crop InputsBayer Contests EPA’s Decision On Valuable Insecticide F…
February 5, 2016
Crop Science, a division of Bayer, has announced it has refused a request by the Environmental Protection Agency (EPA) to Read More
Wheat Field North Dakota
Seed/BiotechSyngenta Wins Seed Fraud Suit Against South Dakota Grow…
February 5, 2016
Syngenta has obtained a $25,000 settlement from Paul and John Mayclin, Mayclin Farms, Plankinton, SD, in response to their Plant Read More
ManagementOABA Annual Conference Wraps Up In Columbus
February 5, 2016
More than 300 Ohio AgriBusiness Association (OABA) members and industry professionals were on hand to engage in collaborative learning and Read More