Herbicide injury in soybean, Japanese beetles, potato leafhoppers in alfalfa, tar spot being found in Marshall and Jones counties (and some additional counties since) at low levels, and some hail damage in NE Iowa were some of the issues observed by ISU Extension field agronomists this last week. Read on to see what’s happening, particularly in the the eastern part of the state.
Terry Basol (Region 4): “Corn and soybeans continue to look good for the area. Corn fields for the area range anywhere from V9 - V11. POST herbicide and side-dress applications are wrapped up and much of the corn is now canopied. So far, corn leaves look really nice and clean of lesions or foliar diseases but continue to scout as recent precipitation events and higher relative humidity levels in the canopy, along with prolonged periods of leaf wetness, are conducive conditions for disease development. Soybeans are at the verge or just starting to flower (R1 stage). Most of the POST herbicide applications are wrapped up, with the occasional re-spray needing to be done due to antagonism in the tank, etc. As far as precipitation, according to the Iowa Mesonet, the NE IA Research and Demonstration Farm here at Nashua has received 4.17 inches of rain for the period of June 21 – July 5, with 2.63 inches received on June 25 and a total of 1.54 inches for the rain that came on July 4 and 5."
Josh Michel (Region 5): “Last Wednesday (June 29) afternoon, a line of severe thunderstorms delivered 0.25 to 1.0 inch of rainfall from Decorah to Dubuque. While this provided some much-needed moisture, unfortunately these storms also produced hail that caused some crop damage in parts of Winneshiek, Allamakee and Clayton counties. Most of the corn in NE Iowa can be staged from V5 up to V10. Soybeans can be staged from V3 up to R1. I was able to find some flowers in some early planted fields. Any last-minute POST herbicide applications are getting finished up for both corn and soybeans. Several fields of oats are starting to turn and look really good at this point. Reports of potato leaf hoppers and grasshoppers continue to come in as the second crop of alfalfa gets put up. Recent field calls and questions have consisted mainly of alfalfa pests and scouting, small grains and forage management, fertilizer sidedressing applications and management, and herbicide injury in soybeans.”
East Central, Southeast, and South-Central Iowa:
Rebecca Vittetoe (Region 8): “While some areas got some much-needed rain last week and over the weekend, other areas missed out or got trace amounts. A good portion of EC Iowa is classified as abnormally dry, and there were days last week where you could see the dry conditions causing corn leaves to roll, especially in lighter soils or more compacted areas. Corn is mainly in the V9 -12 growth stage, and I have started seeing a few tassels sticking out in some fields over the weekend and early this week. Soybeans are flowering (R1) and a few fields are close to R2. A lot of second cutting hay was done last week and over the weekend. Field calls and questions last week mainly involved herbicide injury in soybeans, herbicide performance (weeds not dying), Japanese beetles (particularly in Linn and Johnson counties), and tar spot.”
Virgil Schmitt (Region 9): “Rainfall last week in the counties I cover was extremely variable, ranging from a trace to over two inches. In general, temperatures during the last week in the counties I cover were normal to two degrees above normal. Most corn is V10-V12 and looks good to excellent. Most soybeans are at V6-R2 and also look good to excellent. Oats are turning and cereal rye has turned color, with some already harvested. Last week, I saw a few first cutting hay fields being cut and many second cutting hay fields being cut. Japanese beetles are being found in Jackson County and areas to the south. Potato leafhoppers continue to be present in alfalfa and there are numerous grasshopper nymphs in some grassy areas. A few katydids are “singing.” Phone calls and field visits last week mostly involved herbicide injury, herbicide drift, and tar spot management. With the questions coming in about tar spot, Alison Robertson posted two good articles, which can be found here and here.”
Check out the map below to find your local ISU Extension field agronomist and find their contact information here!