b'ON LOCATION: TAR SPOT SUMMITBreeders Dive into NewTar Spot ResearchAs tar spot continues to cause issues in the Midwest, researchers look to new solutions.Alex MartinWITH SO MANY GROWERSdealing with different issues inIn the future, Cruz would like to see research applied not only the field, its no surprise that tar spot has moved up on every- to tar spot, but also to detecting more diseases through imagery ones list of corn threats. With no genetics fully built to fight tarand prediction. Keep in mindautomation is key for the future. spot offonly genetics that are stable enough to stand against itnew research is needed to fight the emerging disease in the U.S. Understanding Tar Spots CausesIts important to note: tar spot isnt only affecting the U.S.Since the discovery of tar spot in the Midwest in 2015, its been a According to Christian Cruz, an assistant professor in therather complicated disease to understand and spot in the field. Department of Botany & Plant Pathology at Purdue University,While researchers like Cruz are looking into imagery diagnostics, tar spot has been seen in Mexico, as well as Central and Souththeres still some difficulty currently in finding it in the field.America. New to the U.S., other countries have been battling tarTar spot is a sneaky disease, says Damon Smith, an assistant spot in their corn crops as well. professor at the College of Agricultural and Life Sciences at the University of Wisconsin-Madison. Its slow and sneaky at the Imaging for Early Detection beginning, and then it ravishes at the end of the season.Though other countries are battling tar spot as wellwithTypically, the thought after seeing the spots appear on a corn various successes in terms of management stylesresearchcrop is that its game over. Smith says thats because tar spot is is starting to ramp up in terms of tar spot. In Cruzs lab, theyrea polycyclic diseaseit goes through multiple cycles in a single working on focusing on how to better detect tar spot in theseason, and its hard to identify early in the season. field, particularly using images and sensing technologies, to helpSmith, along with a co-researcher Marty Chilvers from reduce some of the time it takes in detection. Michigan State University, is looking into what causes tar spot to We know that nowadays, we rely a lot on humans, Cruz,develop in the field, as well as how to monitor and combat it.one of the speakers at the AgReliant Genetics Tar Spot Summit,Part of it comes down to residue in the fields, which can gives says. Either expert farmers or personnel go to the field to evalu- rise to the disease in the beginning. That means fields with a his-ate whats going on, and then a decision is made. The reality istory of tar spot will continue to have a history and struggle with theres a lot of surveillance poorly carried outpeople are look- the disease. ing in the wrong places at the wrong times. That obviously hasMaybe its coming in early and affecting those lower leaves, an impact on the decisions we make. then moving up the plant. Maybe there are minute amounts of Because of that human errorwhich, Cruz notes, is justcorn residue still left in that soil profile that we cant see, because due to the lack of information on tar spotthere needs to be arememberthese little black spots are very, very tiny, he says. bigger push for better scouting and surveillance.Theres some work trying to understand wheres the inoculum The key of Cruzs research is to start developing tools to com- actually originating from.bine as much data and information as possible to start minimiz- At the end of the day, Smith believes one of the key factors ing the potential for human error in field scouting.that play into it is weather. According to a study in Mexico from Automation is going to be very important, he says. By1995, wetness and moisture were key factors causing tar spot in using imagery in this case, we might be starting to incorporateMexico. But, Smith says you can narrow the disease down even things like weather data into these tools in the future. more, by just considering how wet the leaves are. Imagery and automation can also propel scouting forwardThough tar spot continues to be an issue, Smith says theyve beyond just tar spot. Cruz believes his research can also help infound hybrids that perform well, even under stress of tar spot. diagnosing different diseases or issues in the field.Genetic resistance is going to be forming that foundation for We need to start thinking how we can quantify multiple dis- us, he adds.SWeases at once, Cruz says. 46/ SEEDWORLD.COMFEBRUARY 2023'