As warmer temperatures creep into the forecast each spring, farmers and researchers alike begin to consider just how soon to pull the trigger and put seed into the ground. While these early planting dates may fall slightly outside of what is considered nominal for corn and soybean, certain situations may still provide growers a window of opportunity for early planting. Continue reading
Increase in input costs and lower relative commodity prices compared to last year may tempt some to forgo using a PRE this spring. Since glyphosate and dicamba have actually gone down in price, it may be tempting to try this combination near planting, then hope that dicamba will provide enough residual weed control to hold until those herbicides can be applied again early POST. Continue reading
As general rule, no-till production increases the risks from pests including slugs, cutworm, threecornered alfalfa hopper and several below ground pests such as wireworm and southern corn rootworm. Tillage is not an option in most of Tennessee’s agricultural landscape. This leads entomologists to recommend spring “burndown” applications 4 weeks in advance of planting. The goal is to “break the green bridge” or eliminate alternative hosts (weeds, cover crops) well before planting the cash crop.
However, making burndown applications 4 weeks prior to planting isn’t always possible or it doesn’t align with the goals of having cover crops. One way to help mitigate potential insect issues in late burndown is to add a pyrethroid insecticide with your herbicide application or within 7 days of planting. Beware blooming and pollinator attractive cover crops (vetch, brassica species) may have foraging honey bees and pyrethroids should not be utilized until the plants are not longer attractive to pollinators (desiccated or senescing from herbicides).
Utilizing insecticide seed treatments will offer protection against pest insects that may feed on your cash crop. If you are planting green (not burning down cover crops until after planting) I highly recommend a robust insecticide seed treatment and a pyrethroid insecticide that is included with the burndown herbicide. In corn this would be Poncho 500 or 1250, in soybeans Gaucho or Cruiser treated seed and in cotton Gaucho or Aeris based treatments will offer adequate protection from most below ground and some above ground pests. Keep in mind, seed treatment residual activity is strongly influenced by environmental factors, plant growth and amount of AI on the seed.
Cutworms in corn and cotton are uncommon but can be a serious pest. Pyrethroid applications within a week of planting will significantly reduce the risks of cutworm issues at low cost. Insecticide seed treatments are normally not enough to control cutworms and Bt traits in corn and cotton can offer mixed results depending on the traits. Three gene corn and cotton (those that include the Vip trait) provide better cutworm control than dual gene corn and cotton (V2TP, BG2 etc).
Overall, I like to see farmers planting in grave yard dead fields of weeds or cover crops but that isn’t always the case. Providing protection for your cash crop, at a relatively low expense, may help avoid the painful and costly decision to replant.
Prickly sida or tea weed has increasingly become more of an issue in soybeans. There are two reasons for this. First, the Group 15 herbicides (Dual Mag, Warrant, Zidua) are the most common PRE-applied herbicides utilized. Though that group of herbicides provides good residual control of pigweed and grasses, it provides no help on sida. Second, is that glyphosate nor dicamba has ever been very effective on this weed. The only POST option that can give some control is Liberty. However, even Liberty is limited to controlling only very small (<3”) prickly sida. Continue reading
The combination of some lingering supply chain issues, most notably Sharpen and Verdict are in tight supply, with the ever-increasing presence of herbicide resistant weeds has made burndown time more of a challenge. On a positive note, glyphosate is in great supply and down in price about 40% compared to last year. Continue reading
Results from the 2022 TN soybean variety trials are now available as pdf and excel files and will be posted at search.utcrops.com/soybean. Seventy-five varieties were evaluated in small plot replicated trials (REC) at nine locations and fifty-seven varieties were evaluated in three to nine locations as non-replicated large strip plots (CST). Quality and agronomic traits are reported for the REC trials and disease data are reported for CST trials. A summary of varieties that were in the yield “A group” (not statistically different from the top yield within each test) in either the REC or CST trial can be viewed here 2022 Soybean A Table.
Every fall we travel around the state and observe the overall success or failure of weed control in our row crops. From the Palmer amaranth standpoint a few too many fields look like a failure. Particularly, from Gibson county across to Lauderdale county cotton and soybean fields ranged from clean fields to fields with more weeds than one would like (Picture 1) to completely grown up pigweed messes (Picture 2). Continue reading
I’ve received several calls about looper numbers increasing in soybeans across West Tennessee. Numbers range from 3 per 25 sweeps to 25 per 25 sweeps. Treatment is recommended when defoliation exceeds 20% from R1 to R6 or if looper numbers exceed 19 per 25 sweeps. It’s often suggested to ignore small worms (<1/2 inch) in these counts due to predators and entomopathogens taking a substantial toll on their survival.
Pyrethroid additions, at R3 fungicide timing, can exacerbate looper numbers and shouldn’t be included unless they are needed. This is one of the reasons I caution against including an automatic pyrethroid with fungicides at R3 and those applications won’t have any measurable impact on stink bug numbers when the beans hit R5. Loopers are one of the top pests encountered in late planted soybeans and are the most expensive to control. Further, I received word from my colleagues in Mississippi that low rates of diamides (1.2 fl oz/a Vantacor, 7.0 fl oz/a Besiege, 14.0 fl oz/a Prevathon) are providing unacceptable levels of control in large populations of loopers. This isn’t a surprise but take caution when utilizing diamides. Reports of diamide slippage on loopers has occurred for several years and more often than not, it occurs when low rates are utilized against high numbers (>1.5X threshold). Another product, Intrepid 2F (methoxyfenozide), has also had some control issues in Arkansas and Mississippi. Rates of 4.0 and 6.0 fl oz/a did not provide satisfactory control of loopers 7 days after application; however, Intrepid Edge (methoxyfenozide + spinetoram) performed very well. We have several insecticide options available at our disposal but if you’re facing large numbers, low rates of any product (especially the diamides) probably won’t cut it.
One final comment, don’t confuse soybean loopers with green cloverworms. Loopers have 2 pairs of prolegs cloverworms have 3 (see images below). Cloverworms are much easier to control than loopers and pyrethroids, as well as other insecticides, work well. Information on insecticide options for loopers can be found here: https://guide.utcrops.com/soybean/soybean-insect-guide/soybean-looper/
