{"id":646,"date":"2019-02-15T13:27:32","date_gmt":"2019-02-15T21:27:32","guid":{"rendered":"http:\/\/blogs.oregonstate.edu\/vegnet\/?page_id=646"},"modified":"2021-06-30T13:04:38","modified_gmt":"2021-06-30T21:04:38","slug":"black-cutworm","status":"publish","type":"page","link":"https:\/\/agsci-labs.oregonstate.edu\/vegnet\/pest-profiles\/black-cutworm\/","title":{"rendered":"Black Cutworm"},"content":{"rendered":"\n

IDENTIFICATION<\/h4>\n\n\n\n

Black cutworm larvae are often described as ‘greasy’. Coloring can vary from light grey to almost black. Look for pairs of black spots<\/strong> that occur along the length of the back. These paired spots are uneven in size<\/strong> but aligned diagonal to each other. Adult moths have a distinctive, singular black triangle on each forewing.<\/p>\n\n\n\n

\"cutworms
PHOTO CREDIT: Roger Schmidt, University of Wisconsin-Madison, Bugwood.org, used with permission<\/figcaption><\/figure><\/div>\n\n\n\n

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DAMAGE<\/h4>\n\n\n\n

Cutworms are usually thought of as subterranean pests that feed at or just under the soil surface. Their chewing mouthparts literally ‘cut’ stems of plants as the larvae move about (FIG.2). In fact, 80% of the feeding damage by black cutworm occurs during the final instar of development1<\/sup>. <\/p>\n\n\n\n

However, it is important to recognize that foliar feeding occurs when cutworms are small<\/strong> (FIG.1). This is not so much because feeding on leaves affects plant development, but because late-stage larvae are difficult to detect and treat.<\/p>\n\n\n\n

Sweet corn is most susceptible at the seedling stage, and feeding becomes more tolerable at 4-lf and beyond. The worst case scenario<\/strong> is when moths lay eggs early and corn is planted late. This means that mid- to late-stage larvae are present just as corn is emerging. Review the degree-day section below for more information.<\/p>\n\n\n\n