Aaron Hager, Extension Weeds Specialist, University of Illinois
Nearly all herbicide labels (soil-applied or post-emergence) have rotational crop intervals that specify the amount of time that must elapse between herbicide application and planting a rotational crop. This becomes particularly important with late-season herbicide applications, and when soil moisture is limited. Additionally, the labels of almost all post-emergence soybean herbicides indicate a pre-harvest interval or a soybean developmental stage beyond which applications cannot be made. Labels of some products may indicate both a developmental stage (before soybean bloom, for example) and a pre-harvest interval. Pre-harvest intervals indicate the amount of time that must elapse between the herbicide application and crop harvest. Failure to observe the pre-harvest interval may result in herbicide residue levels in the harvested portion of the crop in excess of established limits.
Talon Becker, Commercial Agriculture Extension Educator, South Central IL
With no rain in the South-Central Illinois region, and last week’s storms being largely scattered with variable totals, crops in the area are starting to show some stress again. This is particularly true for later planted corn, likely due to shallower roots not being able to tap into some of the deeper soil moisture. Earlier planted corn is tasseling with some silks starting to emerge. At this time, most of that corn looks relatively unstressed. With a good chance for rain showing in the forecast for this weekend, hopefully it will stay that way. Early full season beans are close to canopy and in full flower. Double crop beans have largely reached the first trifoliate stage, but growth has slowed with the dry conditions.
Doug Gucker, Local Foods Small Farms Extension Educator, Central IL
Even though this portion of the state received over 2 inches of rain in the past week, it is still rated as being in some stage of drought (abnormally dry to severe drought). Crops look much better after the rains. Most corn fields are at VT and soybeans fields at R1. At the present, reports of corn leaf diseases have been scarce in the area.
Soybean leaf with Japanese beetles and corn at VT.
Chelsea Harbach, Commercial Agriculture Extension Educator, Northwestern IL
Planes are a-flying in Western Illinois this week, which means those fungicide applications are going on in a timely manner. The weather has also been very temperate with little rain, and the outlook is hot, hot, hot, with little to no rain. What does this mean for diseases? Well, I suspect we might have a reprieve from some of the foliar diseases that have been particularly bothersome in years past such as corn tar spot, grey leaf spot, or even Septoria leaf spot on soybeans. Time will tell though, as disease development is 1/3 dependent on a favorable environment for the pathogen (disease triangle!). We do have one confirmed sighting of tar spot on corn in Henry County. I do know that there is more tar spot out there but finding it can be something of an eye strain. The sheer fact is that the disease pressure just isn’t there right now, and that largely has to do with the weather we’ve had and the weather outlook. I posted a write-up about understanding the tar spot disease map on corn IPM pipe. You can refer to that for more information on the subject.
Weston Olson, ILSoyAdvisor Soy Envoy
Crops are moving along nicely with our corn tasseling or about to tassel, which is good timing with the mild weather this week, hoping to not stress the corn out right now. Soybeans are deep into R2 and are getting closer and closer to canopying the rows, unfortunately not soon enough as some patches of Waterhemp have emerged and will beat the soybeans to canopy closure. Going to attempt to cut them out with weed hook, always a fun job. Around us, everyone’s crops look good, as we were dry for a bit but have gotten back on the train of timely rains.