Michael Rethwisch - Extension Educator

Michael Rethwisch

Geographic Responsibilities: Butler/Polk Counties
Program Responsibilities: Cropping Systems
alfalfa weevils

Scouting Advised for Alfalfa and Clover Leaf Weevils April 20, 2017

Alfalfa weevils have been reported damaging alfalfa in north central Kansas and western Nebraska. As temperatures warm up, expect to see alfalfa weevil larvae in southern Nebraska and slightly later, in northern Nebraska. Even with the pressure of planting row crops, it is essential that producers growing high quality alfalfa hay make time to monitor fields for weevils now and over the next few weeks. See the article for a table of treatment thresholds for various alfalfa prices.

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Map showing sites of Nebraska soybean fields in study of yield-limiting production factors
Map showing sites of Nebraska soybean fields in study of yield-limiting production factors

Help Us Identify Yield-Limiting Factors in Nebraska Soybean Fields October 5, 2016

Nebraska soybean producers are being asked to answer a survey about their soybean fields and contribute to a benchmark study of current soybean production in Nebraska. Researchers from 10 north central states, including Nebraska, are collecting the data to identify factors that may be impeding growers from reaching full yield. See what they've learned in the first two years of the study and how they hope to use the information.

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Insect Moth Trap Counts - May 6 May 6, 2016

Moth traps have been established at 12 sites in northeast, east central, southeast and south central Nebraska to monitor flights of armyworm, black cutworm, and variegated cutworm moths.  The results are presented below and will be updated weekly through May.

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Are Soybean Seed-Applied Biostimulants Cost Effective in a Corn-Soybean Rotation? May 6, 2016

Field trials conducted over the past five years on biostimulant soybean seed treatments showed increased value of $9.15 per acre in dryland and $2.93 per acre in irrigated fields for two commercial products.

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Biological control insects and alfalfa aphids
Biological control insects and alfalfa aphids

Aphids Active in Nebraska Spring Alfalfa May 6, 2016

Examination of an alfalfa field in northeast Nebraska this week revealed some alfalfa weevil larvae (under threshold at just over one larvae/sweep) and a surprisingly high population of pea aphids. This was somewhat unexpected due to the recent winds and rain which often dislodge aphids from plant stems, resulting in reduced pea aphid numbers. See story for biocontrol information and aphid scouting and treatment recommendations.

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alfalfa weevil
Alfalfa weevils can cause serious yield loss in first cutting alfalfa

Scout for Alfalfa and Clover Leaf Weevils May 5, 2016

Guide to identifying and managing alfalfa and clover leaf weevils in alfalfa. While research in northeast Nebraska has shown that clover leaf weevil larva feeding does not cause yield reduction to first cutting alfalfa, alfalfa weevil feeding can cause severe losses to yield and quality of the first cutting. This is why it's important to correctly identify the type of weevil feeding causing damage.

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Table of variegated cutworm moth counts for April 1-28, 2016
Variegated cutworm moth counts

Insect Moth Trap Counts - 2016 April 28, 2016

Moth traps have been established at 12 sites in northeast, east central, southeast and south central Nebraska to monitor flights of armyworm, black cutworm, and variegated cutworm moths.  The results are presented below and will be updated weekly through May.

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Cutworm Monitoring Network Established April 22, 2016

Extension educators have organized a pheromone trapping network to monitor black cutworm, variegated cutworm, and armyworm moth activity across Nebraska during the 2016 planting season.   The first traps were put in service the week of April 4.

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