With two thirds of our soybean crop falling under the category of ‘late planted’ whether or not they are following wheat, we are a week or two away from the optimal window for fungicide sprays on late beans.  A fungicide can reduce disease damage to the crop and enable the crop to retain leaves longer resulting in a greener crop later into the season.  However, we do not always improve soybean yields with a fungicide spray.  Yield increase will depend on whether conditions exist to promote disease and on the resistance level of the variety.  Dr. Newman generated sprayed/unsprayed yield response data for all soybean varieties that are included in the County Standardized Testing program posted at utcrops.com.  These are also reported in PB 11-03, the soybean variety book to help guide fungicide decisions.  

• Don’t spray too early.  Spray beans with at least 12-15 nodes that are at R3.  A soybean plant may produce as many as 22 nodes in a season but in a short season scenario we are looking at fewer nodes produced before growth ceases.   Group 3 beans or beans growing under stress will usually produce fewer nodes.   
• A node on a soybean is the location where the leaf attaches to the main stem.  Unfortunately, leaves on the bottom part of the plant drop off and you sometimes have to look for the leaf scars.  The first node is the area where the unifoliate leaves were attached (feel for opposite scars beneath the first trifoliate).  Above this area you will see trifoliate leaves or feel leaf scars that will alternate up the stem (they don’t have a partner opposite on the stem).  Sometimes there are small branches coming out of these areas.  Count scars and trifoliate leaves up the stem to the last trifoliate that has open leaflets at the top of the plant.  The last trifoliate doesn’t have to be full sized but the leaflets should be unrolled and not touching together.  That will be the last node on the plant on that day. 
• R3 means you can look at the top 4 nodes of the plant and find at least one 3/16″ pod on at least one of the 4 top nodes.  The dried bloom tags will cover the tiny pods that are forming for awhile but if you pull it away you should see the small pod.  R3 can last several days to a few weeks with indeterminate soybeans.  Sometimes folks will wait a few more days to let more tiny pods form before pulling the trigger to spray and that is fine. 
• Ground rigs with higher volumes (15 GPA+) of water and pressure can help move material down into the canopy for more effective coverage. 
• Strobilurin or combination products that include one strobilurin will work equally well to control many diseases.  Documentation of  strobi resistant Frogeye Leaf Spot has increased the number of combination products used which is a good management practice.  In rotated ground with no problems controlling disease, strobilurin chemistry can still be a very effective tool. 
• If multiple fungicide sprays are planned, please use a combination product triazole + strobi with at least one of the sprays.  Multiple applications (especially when rates are cut) of strobilurin-only products can help increase the chance of developing fungicide resistance.  Strobi products are great on other plant diseases and are an important tool in soybean disease protection.  We want to keep this tool working for us for as long as possible.
• Skip the spray if disease is not evident and variety has a good disease package.  Later planted beans have a lower yield potential and are growing under drier conditions that can be less conducive to disease development.  Also, later planted beans treated with a fungicide will mature 1 to 2 weeks later in the fall which may not fit into your harvest schedule.