Resistance Management

western bean cutworm in corn
Figure 1. (left) Western bean cutworm causing feeding damage in corn. (Photo by Jim Kalisch and Silvana Paula-Moraes) (right) A green lacewing beneficial insect eating western bean cutworm eggs. (Photo by Julie Peterson)

Which Bt Traits Do You Need to Purchase? March 24, 2017

When it comes to buying corn seed, one way to save money can be to ensure that you don't invest in GMO insect protection traits that you do not need for your particular farm or field. Which corn rootworm, western bean cutworm, or European corn borer traits do you need? This article can help you determine which of the nine types of Bt proteins might best serve your needs.

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marestail

Status of Herbicide-Resistant Weeds in Nebraska March 20, 2017

Nine weed species in Nebraska have now evolved resistance to at least one group of herbicides. Six weed species — common ragweed, common waterhemp, marestail, kochia, giant ragweed, and Palmer amaranth — have confirmed resistance to glyphosate. Rotate herbicide sites of action and weed control practice to avoid contributing to this trend.

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Video: Herbicide Resistance Nothing New March 17, 2017

UNL Weed Scientists on Weed Resistance

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glyphosate-resistant Palmer amaranth
Figure 1. A female glyphosate-resistant Palmer amaranth plant in a soybean field in south-central Nebraska. This plant has the capacity to produce up to half a million seeds. (All photos by Parminder Chahal)

Glyphosate-Resistant Palmer Amaranth Confirmed in South-Central Nebraska March 15, 2017

Palmer amaranth (Amaranthus palmeri S. Wats.) is a C4 dioecious species (separate male and female plants) native to the southwestern United States.

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Bt-Trait-Table-Partial-image

Handy Bt Trait Table Revised for 2017 January 19, 2017

The Handy Bt Trait Table for US corn production has been updated for 2017. It includes information on all registered Bt corn hybrids commercially available and summarizes which insects are controlled by which hybrids, which Bt and herbicide tolerance traits are expressed in different hybrids, and the Insect Resistance Management Refuge requirements associated with these hybrids.

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Photos of pigweed species
Figure 1. Common pigweed species found in the Nebraska Panhandle. Palmer amaranth and waterhemp are ALS-resistant. Images, from top to bottom in each column, are of seed, seedlings, and plants in the vegetative growth stage. (Source Nebraska Extension EC94-138)

Management of ALS-Resistant Palmer Amaranth and Waterhemp in the Panhandle January 6, 2017

Palmer amaranth and waterhemp in the Panhandle are resistant to ALS-inhibiting herbicides. While control of these weeds in dry bean can be challenging, corn, irrigated small grains, and sugarbeet make good rotation options for control. A combined pre/post treatment strategy controls weeds in the early part of the season when crop yield is most impacted and weed species are most susceptible to control inputs.

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Horseweed plant stages
Figure 1. (Top left) Newly emerged horseweed seedlings in the cotyledon stage. (Bottom left) Seedling in the rosette stage with true leaves formed. (Right) Horseweed plants that are early in the bolting stage.

Nebraska Extension Pest of The Month: Horseweed January 5, 2017

Horseweed (marestail, Conyza canadensis L.) is a unique weed species that can emerge in both fall and spring. In Nebraska, unlike the eastern Corn Belt, horseweed populations predominantly emerge in fall as a winter annual.

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UNL greenhouse trial of glyphosate resistance in kochia
kochia in the greenhouse

Managing Glyphosate- and ALS-Resistant Kochia in the Panhandle December 15, 2016

The development and management of pesticide-resistant kochia in dryland and irrigated systems in the Panhandle including a table of herbicide options for Nebraska.

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