By John Tooker
As part of our Black Cutworm Monitoring Network, we continue to detect significant flights of black cutworm moths in our pheromone traps. Since our report last week, three more significant flights have been observed. In these areas, one should expect an elevated risk of cutting damage by caterpillars later in the spring. As reported earlier, on 19 April we detected a significant flight of moths in Potter County. Now we can add significant flights in Lebanon, Lycoming, and Franklin Counties (Table 1). The exact date of the significant flight in Lebanon County is unclear due to some difficulties with the trap, but we made a conservative estimate based on other activity we detected.
Table 1. Details of significant flight of black cutworm moths detected so far this season.
| Nearest municipality | PA County | Date of flight | Degree day
accumulation by 9 May |
|---|
| Ulysses | Potter | 19 April | 45 |
| North Cornwall | Lebanon | Approx. 19 April | 168 |
| Montoursville | Lycoming | 27 April | 82 |
| Lemasters | Franklin | 2 May | 95 |
Cutting damage from black cutworm caterpillars tends to occur about 300 degree days after these flights, so the time to scout has yet to arrive, but could occur next week for Lebanon County. For areas not listed, these degree day accumulations for the closest location can be used to approximate the time to scout, but I usually recommend that fields get scouted every 7-10 days and this “regular” scouting should detect black cutworm damage. When scouting your fields, note that black cutworm caterpillars can damage corn from first emergence up to V4 or V5. For young plants, cutworm damage can look like a series of symmetrical holes through the leaves (see image above). Remember that if cutting damage is found, rescue treatments are usually the most efficient and economical tactic for managing black cutworm. For more information, see our Black Cutworm article.
Source:psu.edu