Recent storms have generated the weather patterns that bring black cutworm moths into our state each year. Pheromone traps picked up the first black cutworm moths of the season during the past two weeks. Predictive models estimate that the first cutworm caterpillars will begin feeding 300 heat units after the first moths are caught. Unseasonably warm temperatures have allowed us to hit that magical number throughout most of the state. This means that cutworm caterpillars have hatched and are out feeding now.
Should you begin spraying tees and greens? Not necessarily because many other factors help determine whether or not black cutworms will actually become a threat to Indiana’s golf courses. Variables such as moth numbers, current temperatures, moisture, natural moth and larval mortality, and impact of beneficial insects, also influence black cutworm populations. Whether or not to treat also depends on where the cutworms are established and whether or not we might tolerate cutworm damage in that area.
The take home message is to scout for cutworm damage or evidence or cutworm caterpillars s on greens and tees. The obvious symptom is aerification holes that don’t heal and/or “C”-shaped scars around the edge of an aerification hole. Make the decision to treat based first on the presence and then on the potential threat of cutworms to those areas. If they need to be treated – NOW is a good time.