Excessive amounts of rain across the Midwest this spring caused many growers to plant — and even replant — corn later than usual. In many areas, corn is as much as three weeks behind where it would be during a normal growing season. Due to the late plantings and unusually wet weather, mid-season pest pressure is expected to be as unpredictable as this year’s weather.
“Pest pressure may not be typical this year, but growers who planted hybrids with HERCULEX Insect Protection have built-in protection against some of the season’s most destructive pests,” says Ben Kaehler, Traits & Germplasm Licensing business leader for Dow AgroSciences. “HERCULEX I Insect Protection protects corn from above-ground pests, including European corn borer, black cutworm, western bean cutworm and fall armyworm, while HERCULEX XTRA Insect Protection provides the same above-ground protection with the added control of corn rootworm.”
While corn earworm pressure is usually confined to seed corn and sweet corn, the late start this year has made field corn an appealing place for earworms to lay eggs. Reports from Illinois in late June indicated corn earworm larvae feeding on leaves still rolled up in whorls in cornfields not even close to silking, as well as fields near the V8 stage.
Insects feeding on whorls near this time of year usually indicate the presence of European corn borer, southwestern corn borer or armyworm. Identifying the correct pest is important before determining the proper control method, but those who planted corn with HERCULEX® Insect Protection can rest assured they are protected from a broad range of damaging pests.
The University of Illinois recently reported that monitoring has started for the Western Bean Cutworm (WBCW) across the Midwest. Last year WBCW was again prevalent throughout Iowa and found as far east as Michigan and Ohio. New reports show that WBCW has been spotted as far north as Canada. Hybrids with HERCULEX Insect Protection are protected from WBCW. In fact, HERCULEX is the only in-plant trait to provide protection from this yield-robbing pest.
Pressure from corn rootworm adults, which is typically observed by early July, has been minimal across the Midwest, but a late emergence of adults is still expected. Because corn is at a younger growth stage due to its late start, corn rootworm adults may interfere with pollination if they cause significant damage to corn silks before pollen shed.
If an average of one or more rootworm adults per plant is found in the next four weeks a Bt hybrid that protects against rootworms is recommended for next season if corn is to be grown there again, said Ric Bessin with the University of Kentucky Extension in a recent Kentucky Pest News issue.
“Planting HERCULEX XTRA will take care of rootworms and their feeding damage on roots before they enter the adult stage, providing protection for your crop and profits,” says Ed King, technology transfer leader for Dow AgroSciences. “Field trials also show a dramatic reduction in the emergence of adult rootworm beetles from plots planted with HERCULEX XTRA.”
Growers who are experiencing very high levels of rootworm adults may consider a pesticide application to minimize damage. Growers should talk to their crop protection retailer to make the best choice for their fields.
“We’re seeing that the traditional economic thresholds for some pests may differ this year,” says King. “Mother Nature and the higher value of corn have thrown many new variables into the equation, and getting advice from a trusted professional who has stayed current on the latest recommendations is a wise choice this year.”