As usual, this past year has been a busy one for all of us. Many new products have hit the marketplace and a number of compounds under development will soon be introduced. This edition of the MARYLAND WEED REPORTER will consist of two parts. The first part will discuss some of the things I have seen and problems I've encountered in 1997. The second part will consist of an update on new products and ideas.
Extension Weed Control Specialist To Contact Me. |
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I've had numerous calls this past Spring regarding weed control problems in small grains. Seems to be more corn cockle and corn flower present than usual. If you look at some of the wild flower plantings on highway medians, these same weeds may be evident, but planted as wild flowers. We need to keep an eye on this to avoid potential weed problems, not only in small grains but other crops as well.
As usual, wild garlic continues to be a problem state-wide. Harmony Extra does a great job, but watch your application timing. In a number of fields I visited, applications were made too early. Not all of the garlic had emerged. Applications of Harmony Extra will work, even at rates less than 0.5 ounce/acre, when applied early. Yet, if all of the garlic has not emerged, a respray will be necessary.
We're continuing to look at Peak as another small grain herbicide. With its 10 month rotational restriction to soybeans, only Fall applications are possible. While it is a superb wild garlic material, there is a concern of carryover to soybeans. In our work over the past 2 years, we have not had any problems with it carrying over to soybeans. If soil pH is high (> 6.8), an STS variety of soybean could be planted.
Annual or Italian ryegrass continues to spread across the state. Hoelon is the only product we have in our battle against this weed. Apply Hoelon early! It only works on small ryegrass plants, and do not tank-mix it with Harmony Extra. Once again, apply Hoelon early! I've seen too many fields where people waited until the ryegrass plants were 6 inches or taller. That is too late!
The last thing I want to mention is bulbous oatgrass. If you're not familiar with it, you're lucky. It produces rather peculiar bulbs in the soil, which gives it part of its name. It is also a tall growing plant, maturing at the same time that wheat matures. Hoelon will not control it. Harmony Extra will not control it. I'm looking at some other products, but need a location for testing. If any of you have a good site, please call.
The season started out on the cold and wet side, and as usual, the faucet shut off. Early on, I had a number of calls regarding control of annual ryegrass, bulbous oatgrass and johnny jump-up. As for annual ryegrass control at planting time, if it is up over 8 to 12 inches in height, Gramoxone Extra will not control it. You need a minimum of 1.5 quarts/acre of Roundup. If you don't get good knock-down control, Accent does a nice job controlling annual ryegrass postemergence in corn.
As for bulbous oatgrass, 2 pints/acre of Gramoxone Extra will suppress it at planting time, but you may have to retreat. Roundup at a minimum of 1 quart/acre also does a nice job suppressing it.. I have yet to see it invade corn once you suppress it at time of planting.
Johnny jump-up requires a minimum of 1 quart/acre of Roundup to suppress it at planting time. Gramoxone at 2 pints/acre also does a nice job in suppressing it. Do not add 2,4-D to Gramoxone or Roundup. We've actually antagonized the performance of these products with 2,4-D, resulting in less control of johnny jump-up. Sometimes, neither Gramoxone or Roundup effectively control this weed and regrowth occurs. Early post applications of Banvel or Marksman may be necessary.
Triazine-resistant common lambsquarters, giant foxtail, smooth pigweed and velvetleaf continue to spread. We've got a few good preemergence programs, but they are not without their risk. Broadstrike products are probably the best for the lambsquarters, pigweed, velvetleaf complex. Within the Broadstrike product line are the following: Broadstrike + Dual, Broadstrike SF + Dual, Hornet (Broadstrike + Stinger), Scorpion III (Broadstrike + Stinger + 2,4-D) and Python (this was called Broadstrike WDG in 1997). Because Broadstrike can be injurious to corn, we recommend that you plant an IR corn line, particularly where a soil insecticide such as Counter is necessary. As for triazine-resistant giant foxtail, Dual has been a consistent performer for us.
Perennial weeds continue to plague farmers as well. A number of postemergence programs are available in corn such as Banvel, Marksman, Beacon + Banvel, Exceed + Banvel, etc. Many of these post programs also do a nice job on triazine-resistant broadleaf weeds. Next year we may have some limited supplies of Roundup-Ready corn. DeKalb will be the only distributor in 1998. Here will be another good tool to use for perennial weed control. I'll discuss it a little further below. Lastly, the use of SR corn in combination with Poast has done a nice job in controlling bad infestations of bermudagrass (wiregrass). This is not a once year program as with most perennial weeds!
Canopy XL (DuPont) and Authority Broadleaf (FMC) were the new boys on the block in 1997. Both products are the same, being a combination of Classic + Authority. Enhanced morningglory control can be expected over Canopy alone, provided you get some rain!
With this agreement between DuPont and FMC, FMC is now selling Assure II and Classic, but under different trade names. The FMC trade name for Assure II is Matador, while the FMC trade name for Classic is Skirmish.
Flexstar also received a label this year. It's basically Reflex with a super adjuvant added. More injurious that Reflex, but has a broader spectrum of broadleaf weed control. Reminds me of Blazer!
Raptor (American Cyanamid) also received its label in 1997. I like this product better than Pursuit because it has better grass and lambsquarters activity. Like Pursuit, it is an early post product. Applications should be made within 14 to 21 days after planting.
The growth of Roundup-Ready soybeans continues. It is a good program providing you drill your soybeans, make your application(s) on a timely fashion and apply the right rate. What I feel will have a bigger impact is the stacked soybean containing the STS and Roundup-Ready genes. First of all, it allows two chemistries to be utilized postemergence, either alone or tank-mixed, without the fear of injury. This is good resistance-management planning. Secondly, Roundup Ultra or Synchrony can compliment one another. For instance, Roundup can be weak on pokeberry while Synchrony does a good job.
Touchdown by Zeneca also received their knock-down labels for use in corn and soybeans. If you're not familiar with Touchdown, it's very similar to Roundup. Zeneca has even petitioned EPA to allow its use on Roundup-Ready soybeans. Differences between the two products is minor. I've noticed that Touchdown has a chemical odor in contrast to Roundup. Also, Touchdown needs a surfactant. Touchdown is a 6 lb/gallon product, so less needs to be used. Finally, some researchers have reported that Touchdown works better under dry, dusty conditions in contrast to Roundup as you may find after small grain harvest.
As mentioned above, Roundup-Ready corn will make its entrance to the marketplace in 1998. DeKalb hopes to have enough seed available to plant close to 1 million acres. As with Roundup-Ready soybeans, there will be a technology fee, probably around $5.00 per acre. Monsanto will have a number of tie-ins with this program utilizing their product line. For instance, the technology fee may be waived if Harness Extra is applied preemergence followed by Roundup Ultra postemergence. This probably isn't a bad idea. With our work with Roundup-Ready corn in 1997, we needed a pre grass base when only 1 application of Roundup was made. Keep in mind a few key points about Roundup-Ready corn for 1998;
- Only one application up to 1 qt/acre will be allowed
- Corn harvested will only be for domestic use
- Volunteer corn in 1999 will not be controlled with Roundup Ultra in Roundup-Ready soybeans
FMC continues to explore the chemistry which led to the discovery of Authority. One of these candidates is called Aim. It will be used as a postemergence treatment in corn. We've looked at it on triazine-resistant and triazine-susceptible weeds. If the weeds have some height, Aim will require a tank-mix with atrazine or Banvel. At times we've also seen some phytotoxicity on corn with this product. FMC is also looking at this product for use in small grains under the trade name Affinity. While I haven't tested it in small grains, rumor has it that Affinity will be better suited for the weed spectrum they have in Europe.
Axiom will be the name of a new preemergence herbicide from Bayer. They're hoping for registration in corn and soybeans for 1998. It's actually a blend of a preemergence grass herbicide plus metribuzin (Sencor/Lexone). Under wet conditions, it has performed well on most annual grass species. There's not enough Sencor in it for broadleaf weed control so atrazine will still have to be tank-mixed with it. Axiom can be weak on nutsedge, so beware!
Rhone-Poulenc hopes to have registration of a new product called Balance for the 1998 season. One niche I see it fitting into is preemergence control of triazine-resistant broadleaf weeds. Rate is critical, though. At rates necessary for season-long control of triazine-resistant common lambsquarters and pigweed, early corn injury may occur. Expect to see marriages of this product! Monsanto will have a package-mix of Harness + Balance. Bayer will also have a package-mix of this product with Axiom.
In 1997, DuPont examined the use of Basis as a preemergence herbicide in corn. Their goal was preemergence control of triazine-resistant broadleaf weeds. For the most part the program was successful. Under heavy weed pressure and low rainfall, the program didn't work. They are reexamining it for 1998. Expect to see a similar program at higher rates. In our own trials with triazine-resistant and triazine-susceptible common lambsquarters, it didn't last through the season. One advantage I see with Basis, though, is its grass activity. Where we added it to our corn prepacks such as Bicep, and applied it preemergence in no-till corn, we achieved a higher level of annual grass control in comparison to where we didn't use it.
BASF hopes to have a new postemergence herbicide called Distinct available in 1998. It's a blend of dicamba (Banvel) + another product which they label as an auxin inhibitor. We've tested it for 2 years and have had good success on most weeds that Banvel has activity on including triazine-resistant lambsquarters and pigweed. We've also had it on perennial weeds and achieved good success. Some pluses as I see it are lower rates and the fact that it has some activity on small grasses.
Novartis will be introducing their new Dual Magnum product line in 1998. Most will be targeted for the midwest. This formulation contains the more active isomer than regular Dual. Novartis may also have a label for a new postemergence herbicide called Action, labeled for corn and soybeans. It's biggest asset is excellent postemergence control of velvetleaf.
In 1997, Monsanto test marketed a combination of Roundup + Harness + atrazine. It appears that this combination will be available in 1998 under the trade name Field Master. One gallon of product per acre will provide 1.5 pt. of Roundup, 2.25 pt. Of Harness and 1.5 qt. of atrazine. Price will run about $21.00 per gallon.
As mentioned above, product like Action and Axiom hope to have labels for corn and soybeans in 1998. With so many players in the market, I hope that competition will drive the prices down. Already, I have heard that DuPont cut the price of Synchrony 70 to 75%, and have also cut the price of Classic by 45 to 50%.
Other new products expecting registration in 1998 are Expert and FirstRate. Expert is a sulfonylurea herbicide from Novartis. It is very similar to Classic in the kinds of weeds that it controls and doesn't control. For instance, both are good in controlling giant ragweed while both are very poor in controlling common lambsquarters.
FirstRate, by DowElanco is part of the sulfonamide chemistry that Broadstrike comes from. FirstRate has both preemergence and postemergence activity. It controls a wide variety of broadleaf weeds. What's interesting is that while it control common lambsquarters preemergence, it has no activity on this weed postemergence. Postemergence rates will be more than one-half the preemergence rates. I would expect to see a postemergence label first.
Other changes include Poast. It appears that BASF will finally sell only one formulation of Poast. What amounts of Poast Plus that are left in the pipeline, will be sold off. One (hopefully low) price will be put on the product for all the crops it's registered for.
Crop
Management School - November 18 - 20, 1997
Contact Betty Marose - 301-405-3929
Hotel - Princess Royale, Ocean City, MD - 410-524-7777
Our Web site is at: http://www.agnr.umd.edu/users/weed/
Most of you know that I can be hard to reach at times.
Yet, I frequently check all of my answering machines throughout the day.
-Office phone/voice mail = 301-405-1329
-Office FAX = 301-490-3754
-Truck phone = 301-412-9858
-Home phone = 301-490-4959
-Email = RR24@umail.umd.edu
*Remember - leave me a phone number where you can be reached when you leave a message. Thanks!
Next time I'll cover changes to our field crops/pest management guide.
Until next time,
Ronald L. Ritter
Extension Weed Control Specialist
Summer 1996 Issue of Maryland Weed Science
Fall 1996 Issue of Maryland Weed Science
