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Black cutworm (Agrotis ipsilon) infestations tend to be associated with tillage practices and weed management1. Reduced– and no-till systems with significant winter annual weed cover, during peak black cutworm (BCW) egg laying, have the highest potential for a BCW infestation. This is because BCW prefer to lay eggs on winter annuals, such as chickweed (Figure 1). A fall herbicide application or tillage can potentially reduce BCW infestations by helping to provide weed free fields in the spring.
Each spring BCW moths migrate from the south and lay their eggs on growing weeds. When the weeds are killed in the spring by a burndown herbicide application, BCW larvae begin feeding on emerging corn. Applying a fall herbicide can help minimize the number and impact of BCW in a field the following spring by reducing weed populations. BCW cause damage that can lower yield potential by:
Fall herbicide applications are becoming a more common practice, especially in reduced– and no tillage fields. Fall herbicide applications help control winter annuals that are preferred by BCW for egg laying in the spring. There are other potential benefits from applying fall herbicides:
Figure 1. Black cutworms prefer to lay eggs on winter annuals such as common chickweed.
The air temperature plays a major role in determining the success of fall herbicide applications. Applications in the fall should be made when temperatures are above 50°F. The weeds need to be actively growing for the herbicide to work. If there has been a killing frost, it is too late to apply a fall herbicide. However, if there have been several light frosts and the weeds have only minor injuries with healthy green leaf tissue, a fall herbicide application may be effective.
This fall applying a Roundup® agricultural herbicide tank mixed with 2-4,D can be an effective way to manage winter annual weeds. A residual herbicide could also be added to the tank mix to provide longer-season control of winter annuals and early germinating summer annuals. A fall application of 2,4-D may provide some short-term residual activity. Table 1 lists specific Roundup® brand agricultural herbicides and tank mixes as well as herbicides with longer lasting residual activity. Always refer to herbicide labels before application.
Growers who plant Genuity® Smartstax® corn products have a mode of action which can provide control of BCW. Traits from these corn products are complimented with Acceleron® seed treatment products, which include clothianidin insecticide to provide additional suppression for BCW. Use of these technologies have the potential to reduce the risk of stand loss from BCW.
Preventative insecticides may be another management option, although some University experts question their worth due to the sporadic nature of BCW infestations2. Several insecticide rescue treatments are available for use if thresholds are met.
If you have questions about fall herbicide applications or BCW management, please contact your local area agronomist.
Sources: 1R.B. Hammond et al. 2009. Black cutworm on corn. Ohio State University Extension Fact Sheet. Publication no. FC-ENT-0035-09; 2A. Sisson, et al. May 5, 2011. Black cutworm scouting advisory 2011. Iowa State University Extension. Integrated Crop Management News ; Additional sources used to created this publication: R.J. Whitworth and H. Davis. February 2011. Black cutworms. Kansas State University Extension. Kansas Crop Pests. Publication no. MF-2954; R. Hammond and A. Michel. 2011. Fall weed control in corn and black cutworm. Ohio State University Extension. C.O.R.N. Newsletter. Publication no. 2011-35; M. Owen. September 27, 2007. Fall herbicide applications—is this a good practice. Iowa State University; M. Renz. October 10, 2006. Late fall herbicide application on herbaceous perennial weeds. University of Wisconsin Crop Management News. Monsanto Company is a member of Excellence Through Stewardship® (ETS). Monsanto products are commercialized in accordance with ETS Product Launch Stewardship Guidance, and in compliance with Monsanto’s Policy for Commercialization of Biotechnology-Derived Plant Products in Commodity Crops. Commercial product(s) has been approved for import into key export markets with functioning regulatory systems. Any crop or material produced from this product can only be exported to, or used, processed or sold in countries where all necessary regulatory approvals have been granted. It is a violation of national and international law to move material containing biotech traits across boundaries into nations where import is not permitted. Growers should talk to their grain handler or product purchaser to confirm their buying position for this product. Excellence Through Stewardship® is a registered trademark of Biotechnology Industry Organization. B.t. products may not yet be registered in all states. Check with your Monsanto representative for the registration status in your state. Roundup Technology® includes Monsanto's glyphosate-based herbicide technologies. Individual results may vary, and performance may vary from location to location and from year to year. This result may not be an indicator of results you may obtain as local growing, soil and weather conditions may vary. Growers should evaluate data from multiple locations and years whenever possible. ALWAYS READ AND FOLLOW PESTICIDE LABEL DIRECTIONS. Roundup Ready® crops contain genes that confer tolerance to glyphosate, the active ingredient in Roundup® brand agricultural herbicides. Roundup® brand agricultural herbicides will kill crops that are not tolerant to glyphosate. Tank mixtures: The applicable labeling for each product must be in the possession of the user at the time of application. Follow applicable use instructions, including application rates, precautions and restrictions of each product used in the tank mixture. Monsanto has not tested all tank mix product formulations for compatibility or performance other than specifically listed by brand name. Always predetermine the compatibility of tank mixtures by mixing small proportional quantities in advance.TripleFLEX® Herbicide is not registered in all states. TripleFLEX® Herbicide may be subject to use restrictions in some states. The distribution, sale, or use of an unregistered pesticide is a violation of federal and/or state law and is strictly prohibited. Check with your local Monsanto dealer or representative for the product registration status in your state. Acceleron®, Genuity®, Roundup PowerMAX®, Roundup Ready 2 Technology and Design®, Roundup Ready®, Roundup Technology®, Roundup®, SmartStax®, Technology Development by Monsanto and Design®, and TripleFLEX® are trademarks of Monsanto Technology LLC. Ignite® and LibertyLink® and the Water Droplet Design® are registered trademarks of Bayer. Herculex® is a registered trademark of Dow AgroSciences LLC. Authority® is a trademark of FMC Corporation. Gangster® is a registered trademark of Valent U.S.A. Corporation. Respect the Refuge and Corn Design® and Respect the Refuge® are registered trademarks of National Corn Growers Association. All other trademarks are the property of their respective owners. ©2011 Monsanto Company. AMB101611