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Tar spot, caused by  Phyllachora maydis , is an emerging disease of corn in the United States. Stromata of  P. maydis  are sometimes surrounded by necrotic lesions known as fisheyes and were previously reported to be caused by the fungus Microdochium   maydis . The association of  M. maydis  with fisheye lesions has not been well documented outside of initial descriptions from the early 1980s. The objective of this work was to assess and identify Microdochium -like fungi associated with necrotic lesions surrounding P. maydis stromata using a culture-based method. In 2018, corn leaf samples with fisheye lesions associated with tar spot stromata were collected from 31 production fields across Mexico, Illinois, and Wisconsin. Cultures of pure isolates collected from Mexico believed to be M. maydis were included in the study. A total of 101 Microdochium / Fusarium -like isolates were obtained from the necrotic lesions, and 91% were identified as  Fusarium  spp., based on initial ITS sequence data. Multi-gene (ITS, TEF1-α, RPB1, and RPB2) phylogenies were constructed for a subset of 55 isolates;  Microdochium ,  Cryptostroma , and  Fusarium  reference sequences were obtained from GenBank. All the necrotic lesion isolates clustered within  Fusarium  lineages and were phylogenetically distinct from the Microdochium  clade. All Fusarium isolates from Mexico belonged to the  F. incarnatum-equiseti  species complex, whereas >85% of the U.S. isolates grouped within the  F. sambucinum  species complex. Our study suggests that initial reports of M. maydis were misidentifications of resident Fusarium spp. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license., Competing Interests: The author(s) declare no conflict of interest.

Invasive organisms pose a global threat and are exceptionally difficult to eradicate after they become abundant in their new habitats. We report a successful multitactic strategy for combating the pink bollworm ( Pectinophora gossypiella ), one of the world's most invasive pests. A coordinated program in the southwestern United States and northern Mexico included releases of billions of sterile pink bollworm moths from airplanes and planting of cotton engineered to produce insecticidal proteins from the bacterium Bacillus thuringiensis (Bt). An analysis of computer simulations and 21 y of field data from Arizona demonstrate that the transgenic Bt cotton and sterile insect releases interacted synergistically to reduce the pest's population size. In Arizona, the program started in 2006 and decreased the pest's estimated statewide population size from over 2 billion in 2005 to zero in 2013. Complementary regional efforts eradicated this pest throughout the cotton-growing areas of the continental United States and northern Mexico a century after it had invaded both countries. The removal of this pest saved farmers in the United States $192 million from 2014 to 2019. It also eliminated the environmental and safety hazards associated with insecticide sprays that had previously targeted the pink bollworm and facilitated an 82% reduction in insecticides used against all cotton pests in Arizona. The economic and social benefits achieved demonstrate the advantages of using agricultural biotechnology in concert with classical pest control tactics., Competing Interests: Competing interest statement: B.E.T. and J.A.F. are coauthors of patents on engineered Bacillus thuringiensis (Bt) toxins (US10704059) and potentiating Bt toxins (US20090175974A1), respectively. T.J.D. is retired and was previously employed by Monsanto, Bayer CropScience, and BASF.