b"aphid population growth, [so theres a] need to spray to avoidwe know we currently have less resistance in forage, Hayes says. harvest issues, Kerns says, noting that scouting and plant- However, Hayes explains there are forage sorghum hybrids on ing dates are crucial to success. Growers have become verythe market with sorghum aphid tolerance and the two industries efficient at management so that we dont have large populationscontinue to work together.building in the field. If youre able to plant early, you can avoid aNearly everything learned about sorghum aphid resistance lot of sorghum aphid problems. in grain sorghum is transferable to forage sorghum, and nearly all Bean says there currently are three main insecticide productssorghum forage breeding programs are working with resistance available. Initially growers only had two insecticides, Transformbreeding, Felderhoff says.and Sivanto Prime, which both act, although differently, at theThe donor source of resistance is a public line, TX2783, nicotinic acetylcholine receptor. and thats a grain sorghum that by chance was a good source, That makes us a little nervous. But fortunately, we now haveHayes says. The forage varieties didn't have that so they were another productSefinawhich is a completely differentstarting more from scratch and that's where molecular breeding mode of action, Bean says. That gives us reassurance that if thetechnologies can really speed up the breeding process for seed aphid becomes resistant to one of the insecticides, we will stillcompanies ready to focus on forage.have an insecticide option to go along with hybrid tolerance. Hayes says relying on natural predator bugs is even better,Successfulso farthough unreliable.Bean says every company now has multiple tolerant hybrids.Beneficial insects are great but hard to control, he adds.In fact, some companies have a lot more tolerant hybrids Anytime we can use genetic resistance, its going to be the firstthan they do susceptible, he says, mentioning that companies and safest approach. rank hybrids for tolerance differently.Kerns agrees that the situation is much less dire than five Future Focus years ago.Researchers emphasize its important to remember that thus far,Our issues with the sorghum aphid have diminished consid-this aphid fight has largely been fought on the battleground forerably over the last three years, but that doesnt mean we won't grain sorghum.have outbreaks, Kerns says. Because a lot of forage sorghum is used on farm for cattleIn fact, Bean has seen more of a problem this year than in production, the reporting and numbers aren't always there, butprevious years with a higher percentage of acres needing to be treated.There has been more spraying in south Texas, and even on up north and into Oklahoma, Bean says. The aphid has seemed to hang around longer. In the High Plains, it normally comes on in the middle of August or September but, this year, it lingered longer and some growers were still having to make applications into October Growers have been successful in integrating a pest manage-ment system using all the tools in their toolbox. If you combine genetic resistance with good stewardship practices and potentially spraying when necessary, that three-pronged approach is going to be the most successful, Hayes says. The fact that the sorghum aphid is now more accurately clas-sified as its own species means researchers are better equipped for the battle. Its a small but meaningful shift in understanding.The primary significance [of the more accurate classification] is to be able to accurately tell when or if a biotype shift occurs in the aphid, and a new source of resistance is needed to control it again, Felderhoff says.Breeders are diligently working to address that biotype shift. The problem is, all of them are using the same mechanism of resistance. That's a problem because if the insect adapts to that mechanism, it very well could affect the vast majority of hybrids that are on the market today, Hayes says. The traits we're using won't last forever. At some point it's very likely we'll have a change.SW34/ SEEDWORLD.COMDECEMBER 2023"