We recently rated our Italian ryegrass screen in the greenhouse for glyphosate and clethodim resistance. The first two runs were conducted on 13 populations across 11 counties in West Tennessee. Continue reading
Practically every fall some growers are dismayed at the vine infestations present at corn harvest. Often, these weed infestations emerged after the PRE applied or early POST applied herbicides had played out. They grew very little until August and as the corn dried down and light became more available those established weeds started rapidly growing. Continue reading
My understanding is that Tennessee may have as many as 100,000 acres of canola planted this fall. Weed management in canola can be difficult, but is fairly straight forward for 2 reasons. Continue reading
The two best fall-applied options for ryegrass and poa control in wheat are Anthem Flex and Zidua. Pyroxasulfone is providing the grass control in both these herbicides.
Anthem Flex may be applied as a true PRE right behind the drill. Oftentimes this use pattern is safe for wheat. However, some stand reduction may occur if wheat is planted and Anthem Flex is applied PRE to dry soil and a rain event happens shortly after sowing. As such, if rain is in the forecast wait and apply it later as a delayed PRE or early POST.
Zidua is typically applied delayed PRE to early POST. The earlier it can be applied the more effective it can be as it has no impact on emerged ryegrass. The earliest it can be applied as defined by the label is as a delayed PRE. The Zidua label defines delayed PRE as when 80% of germinated wheat seeds have a shoot at least ½” long until wheat spiking.
In past years, many have tankmixed metribuzin with Zidua or Anthem Flex. Metrubuzin can cause some significant wheat injury. Predicting wheat injury with metribuzin can be very challenging as so many factors are involved. Weather, wheat maturity, soil type, metribuzin rate and variety sensitivity all play a role on if injury will occur or not. As such I would recommend to NOT tankmix in metribuzin. The main weed target for metribuzin is poa. The pyroxasulfone should keep poa from emerging and therefore metribuzin does not provide much benefit. That weighed against the chance of considerable crop injury when applied to wheat just getting established really points to keeping
The use of precision agricultural technologies is rapidly advancing in row crop production. The latest of these technologies includes the introduction of ground sprayers that utilize AI technology for making targeted pesticide applications. The goal was to enable growers to reduce herbicide use while increasing crop production by precisely targeting weeds. Some questions have been raised about whether there are any additional benefits to this technology beyond reduced pesticide use.
Some of these sprayers are equipped with two separate tanks, each with its corresponding plumbing and boom. A single sprayer can utilize a dual boom system, where two pesticides can be sprayed simultaneously but not mixed. This allows a grower to make a broadcast application in one boom and use the targeted application boom to only turn on when a weed is detected. While you may see a decrease in pesticide use with the targeted application boom, you may also observe a beneficial effect when certain herbicides are sprayed separately, rather than being tank-mixed. Continue reading
Italian ryegrass is becoming one of the most troublesome weeds in the Mid-South for many reasons, including herbicide resistance. Herbicide-resistant Italian ryegrass is particularly problematic due to its ability to survive applications of glyphosate and clethodim. The most effective way to control ryegrass is to prevent emergence by applying residual herbicides in the fall. Tennessee has many relatively hilly fields, which raises concerns about soil erosion without some winter plant coverage. Although fall residual herbicides are effective for controlling ryegrass, the limited time available during the busy harvest season often makes applications impractical. Continue reading
Pigweed problems are nothing new for growers across the region. With Palmer amaranth having confirmed resistance to five herbicide modes of action in Tennessee, control options continue to be limited. Historically, bleacher (Group 27 HPPD inhibitors) applications have provided sufficient control, especially in corn. In recent years, there has been growing concern for the level of control observed when using these products. Continue reading
Serious infestations of goosegrass have proven to be way too persistent in many cotton and soybean fields (Picture 1). Many are getting frustrated with the lack of control seen with tankmixes that contain glyphosate and/or clethodim. Some have asked if maybe some of these grasses have developed resistance to glyphosate and/or clethodim. Continue reading