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Posted 28 June 2013. PMN Crop News.

Pests to Keep in Mind: Black Cutworm, Potato Leafhoppers, and Slugs

Monitoring networks and field observations around the state help fine-tune scouting activities

Source: Penn State University Press Release.

University Park, Pennsylvania (June 11, 2013)--Growers should stay alert for black cutworm damage. Penn State’s Black Cutworm Monitoring Network detected five “significant flights” and the entire state has since exceeded the 300 degree-day threshold telling us that cutting damage should be evident. We found cutting damage here in Centre County at the end of last week. Remember to scout even if you use transgenic varieties targeting black cutworm and insecticide-treated seed—cutworms have been known to feed right through some of these technologies—well-timed scouting and spot rescue treatments are usually the most economical strategy for managing black cutworm. For more details on black cutworm, its biology and management options see our fact sheet.


Potato leafhopper populations are active in alfalfa fields across the fields. Hot dry temperatures can really speed develop of this pest, so the recent cooler weather and rain will help slow them down. Nevertheless, be aware that they have arrived and some folks have reported populations that exceed economic thresholds. With the higher value of hay, our forage specialist has calculated new economic thresholds in our revised fact sheet.

With the return of some wet weather, slugs have an opportunity to become problematic. These slimy mollusks can quickly decimate newly sprouted fields, so be sure to scout low-lying fields or those with heavy residue. Corn seedlings often can grow out of seemingly serious damage, but soybeans are at a great risk because their growing tip is above ground and can easily be killed. If the upper leaves are more or less free of damage, chances of the corn growing out of it are pretty good. If rescue treatments are warranted, act quickly. See our factsheet for details and control option for slugs.

John Tooker