{"id":250,"date":"2017-06-16T14:29:45","date_gmt":"2017-06-16T22:29:45","guid":{"rendered":"http:\/\/blogs.oregonstate.edu\/vegnet\/?page_id=250"},"modified":"2021-07-29T11:27:01","modified_gmt":"2021-07-29T19:27:01","slug":"corn-earworm","status":"publish","type":"page","link":"https:\/\/agsci-labs.oregonstate.edu\/vegnet\/pest-profiles\/corn-earworm\/","title":{"rendered":"Corn Earworm"},"content":{"rendered":"

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The subfamily Heliothinae contains many, globally important crop pest species. As a group, these moths can be light tan-colored with various degrees of patterning on the wings, or brightly colored. Individuals of the same species can exhibit extreme morphological variation, which makes identification difficult.<\/p>\n

Further confusion comes from common names that have been used for decades; Helicoverpa zea<\/em> is called tomato fruitworm, corn earworm, and cotton bollworm, whereas flax bollworm, tobacco budworm, and false corn earworm all refer to different Heliothis<\/em> spp.<\/p>\n

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A 1917 document from the USDA discusses this “one mighty pest”. (click to read the publication)<\/figcaption>\n <\/figure>\n

It is important to recognize similarities and differences between these two Heliothine moths. Confusion over ID in traps can affect spray decisions<\/strong>.<\/p>\n

Corn earworm<\/strong> (Helicoverpa zea<\/em>) activity tends to peak later in the season, coinciding with corn silking. However, early spring flights are possible, and since this species has a wide host range, it can feed on fruiting tomatoes, peppers, etc.<\/p>\n

False corn earworm<\/strong> (Heliothis<\/em> phloxiphaga<\/em>), on the other hand, is common throughout the year. It can be a major pest of mint and outbreaks have been known to occur in the Willamette Valley (2008 and 2010).<\/p>\n<\/span>\n\n\n\n\n\t\n\n\t\n\t\n\t\n\t\n\t
<\/td>False Corn Earworm<\/b>
\n Heliothis phloxiphaga<\/i><\/th>		Corn Earworm<\/b>
\n Helicoverpa zea<\/i><\/th>\n<\/tr>\n<\/thead>\n
Wingspan<\/td>28-35mm<\/td>32-45mm<\/td>\n<\/tr>\n
ID (adult moth) (FW-forewing, HW-hindwing)<\/td>green eyes
\nFW: tan with intricate patterning<\/u>, however this can be rubbed off as wing scales are damaged in traps. Reniform spot not well defined<\/u>.
\nHW: cream colored, HW margin dark with white patch and discal spot thick and PROMINENT<\/u><\/td>		green eyes
\nFW: pale yellow to olive green with dots at scalloped edge, dark grey reniform (kidney-bean shaped) spot present<\/u>.
\nHW: cream colored with dark veins, HW margin dark with white patch but discal spot light or ABSENT<\/u><\/td>\n<\/tr>\n
Larval hosts<\/td>mint, gumweed, columbine, apple, pear, peach, elms, ornamentals<\/td>corn, tomato, cabbage, pea, pepper, snap bean, many others<\/td>\n<\/tr>\n
Flight activity in PNW<\/td>APR-SEPT with 2 evident peaks. Usually sporadic, but outbreak years can occur, such as 2008. Widespread in U.S., does overwinter in PNW<\/td>usually mid-AUG to OCT, but may have activity in JUN, depending on year.
\nA Washington trapping study found CEW became active ~6 weeks after PHX in spring, and the pattern was consistent over many years. Considered migratory, but overwintering in PNW is unknown<\/td>\n<\/tr>\n
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