D3511: Observation on corn leafhopper (Dalbulus maidis) and red stunt in the season 2024 in Texas state

The corn leafhopper, Dalbulus maidis (Hemiptera: Cicadellidae), is a vector for four corn pathogens: the bacterial diseases corn stunt spiroplasma (CSS; Spiroplasma kunkelii), maize bushy stunt phytoplasma (MBSP; Candidatus Phytoplasma asteris subgroup 16SrI-B), and the viral diseases maize rayado fino virus (MRFV; family Tymoviridae; genus Marafivirus) and maize striate mosaic virus (MSMV; family Geminiviridae; genus Mastrevirus). These pathogens cause a severe disease complex in corn known as red stunt. In the U.S., corn leafhoppers and some of their associated diseases were commonly reported from 1945 to 1980. They re-emerged as a pest in South Texas in 2016, and during 2024 had become widely distributed throughout much of Texas along with red stunt disease symptomology. Early planted corn seemed less affected by red stunt compared to later plantings and did not exhibit widespread disease symptoms. Significant reduction in yields were attributed to the red stunt disease complex in 2024. Early-season management of corn leafhopper is critical to prevent disease transmission. Seed treatments appear to be crucial for reducing corn leafhopper populations for approximately 20 days postemergence. Foliar insecticides, such as pyrethroids, dimethoate, and flupyradifurone, have demonstrated efficacy against corn leafhopper and are important for preventing disease transmission through the V8 stage. Continued monitoring of corn leafhoppers is essential, and further studies on controlling this pest are necessary to prevent worsening red stunt problems.