Data from Beck’s Practical Farm Research (PFR)® studies show that there are several multiple mode of action (MOA) fungicides, that when applied at VT/R1, have provided a positive return on investment (ROI). When applying a fungicide, farmers not only expect to protect their crop from yield-robbing leaf diseases but also to improve late-season standability by reducing stalk rot infection and maximizing harvestability.
Categories: Agronomy, Agronomy Talk
Floppy corn syndrome is a root development issue that can occur between the V4 to V8 growth stages. This syndrome results in plants “flopping” or tipping over for a period of time and may lead to yield loss if the plants don’t recover. Interestingly, the plant usually shows visual signs before the physical tipping of the plants.
Utilizing a broad-spectrum fall (post-harvest) burndown can help reduce the soil weed seed bank by controlling winter annual and perennial weeds. It can also offer several auxiliary benefits to row crop fields. Beyond the goal of reliable weed control, a fall herbicide application has many benefits. It can reduce host plants for pathogens such as soybean cyst nematode (SCN), over-wintering insects, and even diseases in warmer climates, and it can help maintain soil moisture in drought-stressed/arid climates. Fall herbicide applications also enable fields to be planted as soon as weather conditions allow; and help soil warming and drying in the spring, especially no-till fields. The net result is a more uniform crop emergence with fewer abiotic and biotic stressors.
To be successful in non-GMO soybeans fields, especially those with weeds resistant to multiple herbicides, apply the same management principles as GMO soybeans. These principles become more critical with non-GMO soybeans because rescue options are much more limited.
There are many effective post-emerge herbicide options available, but what happens if the soybeans are beyond the growth stage at which Liberty® can be applied? Depending on the trait platform, once we reach the R1 growth stage, soybeans must be managed like a glyphosate-tolerant soybean.
Enlist One® or Enlist Duo® 2,4-D choline are both very effective on glyphosate-resistant (GR) marestail, giant ragweed, and waterhemp. Just like glyphosate, Enlist One is a systemic herbicide, meaning coverage is not as crucial as it is with a contact herbicide. One approved tank-mix partner for Enlist One is Liberty®. The addition of Liberty provides two effective SOAs for GR marestail, giant ragweed, and waterhemp. When spraying Liberty alone, Beck’s Practical Farm Research (PFR)® data has shown a 12% increase in control when using a carrier volume of 20 GPA vs. 15 GPA.
Enlist One® + Liberty® is very effective when it comes to glyphosate-resistant (GR) broadleaf weeds, especially in high-pressure scenarios. However, there may be other weeds, like grasses, that you are trying to control.
Soybean rust, (Phakopsora pachyrhizi), a serious disease of soybean and other legumes, was first discovered in the continental U.S. (Louisiana) in 2004. This disease has been reported to cause upwards of 80 percent yield loss when present under optimal, conducive conditions. Current soybean varieties grown have little to no resistance to soybean rust, thus making proper identification and management decisions even more crucial, as we begin/continue harvest in our area.
Beck’s Practical Farm Research (PFR)® data has shown Enlist One® + Liberty® resulted in very effective control of glyphosate-resistant (GR) waterhemp and marestail.
What is the best time of day to make Liberty applications?
Liberty® and glyphosate are considered to be weak acid herbicides. Water hardness will greatly influence the performance of a weak acid herbicide. Much of the spray water many applicators use comes from wells and is considered to be “hard water.”
Contact products like Liberty® require proper coverage to achieve successful weed control. One factor that will influence coverage is the carrier rate. Beck’s Practical Farm Research (PFR)® data shows a 12% increase in waterhemp control when Liberty is sprayed at 20 GPA vs. 15 GPA. Contact herbicides do not move in the plant like a systemic herbicide such as glyphosate does. Therefore, control will be heavily impacted if a contact herbicide does not cover the entire plant.
Glyphosate is effective on many of the same weeds on which Liberty is weaker, like grasses, velvetleaf, etc. Therefore, manage a Liberty + glyphosate application just like Liberty alone, since the Liberty is doing the heavy lifting.
Contact products like Liberty® require thorough coverage due to lack of herbicide movement in the plant. This means that the herbicide must come in contact with the plant tissue in order to achieve control. Systemic products such as glyphosate can translocate throughout the plant, making coverage not as crucial.
Canopy closure is one of the best defenses to prevent the germination of weeds. The competition from canopy closure will reduce the amount of light, making it much harder for weeds to germinate. When applying a pre-emerge herbicide, followed by an in-season residual, the goal is for the blanket of protection to last until canopy closure. Therefore, it is critical for the residual herbicide to last until canopy closure, which may not occur on wider rows. Beck’s Practical Farm Research (PFR)® data shows narrow rows can help reduce waterhemp pressure in the untreated check.
Do you face the same challenging weeds you faced 20 or 30 years ago? In the past 30 years, farmers have adopted more soil conservation practices such as no-till and shallower tillage methods. This shift in tillage practices will impact the weed species in your fields.
Cover crops not only play an important role in soil heath, but also in weed control. Cover crops can reduce selection pressure on current, effective herbicide options, and they can also suppress weeds due to the large amounts of biomass they produce. Similar to canopy coverage, biomass will shade the soil and reduce weed emergence.
WHAT IS A WINTER ANNUAL?
Winter annuals will germinate in the fall, overwinter, and produce seed in early spring and summer. Common examples include marestail, henbit, purple deadnettle, prickly lettuce, common chickweed, shepherd’s purse, pennycress, etc. Most winter annuals will overwinter as a rosette and bolt in the spring, producing seed in early summer. However, marestail can have extended germination which can result in additional flushes of weeds in the spring and even early summer.
One of the first steps to a successful herbicide program is starting clean to allow the pre-emerge herbicide to reach the soil surface. The burndown also allows the opportunity to utilize other “effective” SOAs that can’t be used in-season such as Gramoxone® SL 2.0. Spraying early in the spring provides the opportunity to control winter annuals like marestail as well as emerging summer annuals such as giant ragweed.
Beck’s Practical Farm Research (PFR)® data shows the importance of using pre-emerge herbicides with multiple effective SOAs in order to lay the foundation for a successful herbicide program. The question is whether the pre-emerge herbicide will last until canopy closure. Once we reach canopy closure, the limited light makes it difficult for new flushes of weeds to emerge.