Pest & Crop

Newsletter


Purdue Cooperative Extension Service

IN THIS ISSUE

Issue 8, May 18, 2017 • USDA-NIFA Extension IPM Grant




Insects, Mites, and Nematodes

Weeds

Plant Diseases

Weather Update

INSECTS, MITES, & NEMATODES




A Busy Black Cutworm Catching Season (John Obermeyer and Christian Krupke) -



  • Thanks to the pheromone trap cooperators!
  • Near record number of moths caught this spring.
  • According to heat unit accumulations, NOW is the time to be scouting!

Every spring, dozens of cooperators throughout the state put forth considerable effort in trapping for the arrival and intensity of black cutworm moths. This year, especially, they were very busy showing off their counting skills! I’m personally indebted to these faithful bug counters, hoping you also appreciate their efforts as reported in the “Black Cutworm Adult Pheromone Trap Report.” If you recognize a name or two on this list of reporters, by county, please thank them!

As you can see from the past year’s trap comparison graph, 2017 black cutworm moth catches started at an incredible pace. With this and a larval development model (see the accompanying “Black Cutworm Development Map”) it allows us to alert pest managers to be scouting emerging corn.

NOW IS THE TIME TO SCOUT!!!

Scout high-risk fields for cutworm corn leaf feeding and/or cutting. Don’t be overly reliant on seed-applied insecticides or traited corn to protect your stand, they will not withstand severe pressure. Fields yet to be planted to corn are especially prone to damage, as the cutworms are likely established and feeding on weedy growth as you read this.

Happy Scouting!


Black cutworm moth catch comparison.

Black cutworm moth catch comparison.



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Black Cutworm Adult Pheromone Trap Report



County Cooperator BCW Trapped
Wk 1
3/23/17-3/29/17
Wk 2
3/30/17-4/5/17
Wk 3
4/5/17-4/12/17
Wk 4
4/13/17-4/19/17
Wk 5
4/20/17-4/26/17
Wk 6
4/27/17-5/3/17
Wk 7
5/4/17-5/10/17
Wk 8
5/11/17-5/17/17
Adams Kaminsky/New Era Ag     13 35 61* 48* 30* 21
Adams Roe/Mercer Landmark 11 17* 7 42 28* 35* 40* 54*
Allen Anderson/Syngenta Seed   0         12 1
Allen Gynn/Southwind Farms 2 1 0 15 21* 52* 50* 46*
Allen Kneubuhler/G&K Concepts - Trap 1   0 19* 36 60* 41*   24
Allen Kneubuhler/G&K Concepts - Trap 2   9 2   0 10   1
Bartholomew Bush/Pioneer Hybrids 1 13* 13 17 28* 36* 38* 4
Clay Bower/Ceres Solutions - Clay City 0 0 7 4 2 4 0 0
Clay Bower/Ceres Solutions - Bowling Green 0 0 0   1 1 0 0
Clay Bower/Ceres Solutions - Brazil 0 0 0   0 0 0 0
Clinton Emanuel/Boone Co. CES 8 9 6 10 5 8 14* 3
DeKalb Hoffman/ATA Solutions 0 0 0 1 0 3 3 1
Dubois Eck/Purdue CES 14 28* 41* 4 4 40* 16 6
Elkhart Kauffman/Crop Tech Inc. 0 0 6 16 28* 36* 20*  
Fayette Schelle/Falmouth Farm Supply Inc. 5 33* 5   3 10 14  
Fountain Mroczkiewicz/Syngenta 7 18* 31* 93* 43* 44* 50* 22*
Fulton Jenkins/N. Central Coop - Talma 0 5 10 13 6 39* 5 7
Fulton Ranstead/NCC Coop - Rochester 0 0 0 3 6 11 1 1
Gibson Schmitz/Gibson Co. CES       0 0 0 1 0
Hamilton Campbell/Beck's Hybrids 14 13 18 55* 30* 45* 5 20
Hamilton Truster/Reynolds Farm Equipment   1   1 2 4 0  
Hendricks Nicholson/Nicholson Consulting 0 3 4 11 17* 6 98* 6
Jasper Overstreet/Jasper Purdue CES 2 5 0 5 10 12 20 25
Jasper Ritter/Brodbeck Seeds 1 3 10 32 28* 10 7  
Jay Boyer/Davis PAC   3 14 19 19 43* 28* 34*
Jay Shrack/Ran-Del Agri Services 1 3 5 9 8 9 16 21*
Jay Temple/Jay County CES                
Jennings Bauerle/SEPAC 0 0 0 0 0 0 5 0
Knox Bower/Ceres Solutions - Freelandville 0 0 0 13* 4 3 0 0
Knox Bower/Ceres Solutions - Vincennes 0 0 0   2 2 4 5
Kosciusko Klotz/Etna Green 0 0 4 9 5 41* 21* 3
Lake Kleine/Kleine Farms 4 16* 60* 83* 90* 62* 69* 123*
Lake Moyer/Dekalb Hybrids - Shelby 5 5 20* 27 6 5 7 2
Lake Moyer/Dekalb Hybrids - Schneider 2 5 5 12 20 12 14 14
LaPorte Rocke/Agri-Mgmt Solutions     4 41 9 38*   13
Madison Truster/Reynolds Farm Equipment   0   0 0 0 0  
Marshall Harrell/Harrell Ag Services   0 0 0 0 0 0 0
Marshall Klotz/SR 10 & SR 331 0 0 0 8 9 20* 7 9
Marshall Miller/North Central Coop 0 0 0 2 1 9 5 4
Miami Early/Pioneer Hybrids 0 0 0 3 2 3 0 0
Newton Moyer/Dekalb Hybrids - Lake Village 2 6 2 8 8 21 10 19*
Porter Leuck/PPAC 5 3 18 25 8 22 6 2
Pulaski Capouch/M&R Ag Services 0 0 1 10 10 8 2 1
Pulaski Leman/North Central Coop   0 10 21 30* 23 1 3
Putnam Nicholson/Nicholson Consulting   2 6 2 8 2 4 3
Randolph Boyer/DPAC   1 0 1 2 4 1 1
Rush Schelle/Falmouth Farm Supply Inc.   6 10 1 3 17* 0  
Shelby Fisher/Shelby County Co-op 2 3 5 5 0 10   6
Shelby Simpson/Simpson Farms 7 49* 41* 67* 37 41* 27* 27*
Starke Capouch/M&R Ag Services 0 0 6 28 21* 22* 10 8
Starke Wickert/Wickert Consulting - California Twnshp 1 1 3 4 11 37* 18* 18*
Starke Wickert/Wickert Consulting - Railroad Twnshp 0 0 0 0 9 17* 11 8
St. Joseph Barry/Helena     1 3 15* 20* 7 5
Sullivan Bower/Ceres Solutions - Farmersburg 0 1 2 14 18* 6 1 2
Sullivan Bower/Ceres Solutions - Sullivan 6 21* 14* 16* 6 7 4 5
Tippecanoe Bower/Ceres Solutions 0 0 0 7 3 12* 9 0
Tippecanoe Westerfield/Monsanto Research Farm 0 0 13 11 16 8 18*  
Tippecanoe Nagel/Ceres Solutions 30 47* 44* 89 14 8 16 21
Tippecanoe Obermeyer/Purdue Entomology 2 5 11 5 20* 9 11* 3
Tipton Campbell/Beck's Hybrids 10 17 11 73* 33* 119* 8 31*
Vermillion Bower/Ceres Solutions   0 0   0 0 0 0
Wabash Enyeart/North Central Coop       0     25  
Whitley Walker, Richards/NEPAC1 - Main 10 28* 37* 81* 87* 149* 90* 67*
Whitley Walker, Richards/NEPAC2 - Kyler 3 8 17* 36* 33* 79* 45* 28*

* = Intensive Capture...this occurs when 9 or more moths are caught over a 2-night period


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Black Cutworm Development Map



total precipitation

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Armyworm Pheromone Trap Report



County Cooperator Wk 1 Wk 2 Wk 3 Wk 4 Wk 5 Wk 6 Wk 7 Wk 8 Wk 9 Wk 10 Wk 11 Wk 12
Dubois SIPAC Ag Center 0 0 0 101 193 16 0 3        
Jennings SEPAC Ag Center 0 1 1 56 57 9 4 32 4      
Knox SWPAC Ag Center 0 13 26 42 189 57 2 10 20      
LaPorte Pinney Ag Center 0 0 3 352 936 382 154 445 750      
Lawrence Feldun Ag Center 4 108 216 246 650 348 112 31 40      
Randolph Davis Ag Center 0 29 41 528 1232 300 72 10 298      
Tippecanoe Meigs 0 2 15 107 730 243 98 95 86    
Whitley NEPAC Ag Center 0 34 90 537 1689 1349 855 665 1265      

Wk 1 = 3/16/17 - 3/22/17; Wk 2 = 3/23/17 - 3/29/17; Wk 3 - 3/30/17 - 4/5/17; Wk 4 - 4/7/18 - 4/12/17; Wk 5 - 4/13/17 - 4/19/17; Wk 6 - 4/ 20/17 - 4/26/17; Wk 7 = 4/27/17 - 5/3/17; Wk 8 = 5/4/17 - 5/10/17; Wk 9 = 5/11/17 - 5/17/17

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WEEDS




Purdue Offers Herbicide Resistant Weed Screening (Joe Ikley, Travis Legleiter and Bill Johnson) -



The Purdue Weed Science group is again offering herbicide resistance screening for Palmer amaranth, waterhemp, and giant ragweed for the 2017 growing season.  The resistance screens include glyphosate (group 9) and ALS-inhibitor (group 2) assays for giant ragweed, as well as glyphosate (group 9) and PPO-inhibitor (group 14) resistance screening for waterhemp and Palmer amaranth. We test for the most common mechanism of PPO-inhibitor resistance in waterhemp and Palmer amaranth.

PLEASE READ THE FINE PRINT: An important point to mention here is that researchers are discovering new mechanisms of resistance to these herbicides.  New mechanisms of resistance require us to develop new assays to test for these mechanisms. At the current time we do not have the capability to test for all of the known resistance mechanisms, but we can test for the mechanisms that are currently occurring most frequently in the field.  Please be sure to read the submission form and results form closely when you submit samples and receive results.

Leaf tissue samples can be submitted for molecular DNA analysis that will allow results to be generated within a few weeks of submission.  It is important to follow the directions on the submission form for collecting, storing, and shipping leaf tissue samples as this can have a large impact on the accuracy of the results. A video demonstrating the proper sample collection and shipping process can be found below.



Seed samples can also be submitted for analysis of herbicide resistance.  This allows us to also screen for glyphosate resistance in giant ragweed.  It is also important to follow the directions on the submission form for seed collection from the appropriate number of plants to assure quality results.  The seed samples will take several months to return results as plants will need to be grown from seed in the greenhouse.

The submission form with instructions for collection, storage, and shipping can be found at the following link: https://ag.purdue.edu/btny/weedscience/Documents/HerbicideResistancescreeningform.pdf.  The submission form can also be found on the front page of the Purdue Weed science website: https://ag.purdue.edu/btny/weedscience/Pages/default.aspx.

Please contact Julie Young (young294@purdue.edu, 765-494-0891) or Todd Abrahamson (abraha15@purdue.edu, 765-494-7071) with any questions or concerns you have when sampling or shipping a sample.

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PLANT DISEASES




Problems in Ponded Corn(Kiersten Wise and Gail Ruhl) -



Heavy rain and ponding in Indiana cornfields this spring have increased the prevalence of seedling blights. Two minor diseases, crazy top and Physoderma brown spot, may also be problematic in areas where corn was underwater for 24-48 hours.

Seedling blights are prevalent when cool, wet soil conditions persist after planting. These conditions favor infection by many of the organisms that cause soil-borne diseases. Cool, wet soils also slow plant growth and development and give pathogens more time to infect and damage the seedling.

Seedling blights are caused by a variety of soil or seed-inhabiting fungi. Infected seeds may rot after germination, preventing emergence, and plants that emerge have reduced root development and are often stunted. Roots of infected plants may be brown and discolored and can be soft or mushy. Infected plants may also have brown discoloration on the mesocotyl. Two of the most common seedling blights of corn are caused by Pythium and Fusarium species. Remember that to accurately determine the specific organism responsible for a suspected seedling blight issue, it is necessary to submit samples to a diagnostic lab such as the Purdue Plant and Pest Diagnostic Lab. This video demonstrates how to sample fields to diagnose seedling blight and stand establishment issues.




The risk of corn seedling blight decreases when crops are planted into warm, dry soils. These conditions allow seedlings to germinate and emerge rapidly. However, it is often necessary to plant into less than ideal soil conditions, and fungicide seed treatments provide some protection against seedling blights.

Crazy top is caused by a fungal-like organism called Sclerophthora macrospora. This pathogen survives in soil and infects young corn plants when there is excess rain or ponding in the spring. Crazy top symptoms are most commonly observed at tasseling when distorted and malformed tassels appear in areas that were ponded or saturated (Fig. 1). However, in some fields symptoms may be less diagnostic, and include stunting, tillering, thin, yellow leaves, and barren plants.



Fig. 1. Crazy top.

Fig. 1. Crazy top.

Physoderma brown spot is caused by the fungus Physoderma maydis, and also survives in soil and residue and infects corn plants when plants are ponded or excess water remains in the whorl. The symptoms typically appear in the late vegetative stages through pollination and are characterized by very small chocolate brown or yellow lesions on the leaves and midrib (Fig. 2). The lesions may appear in a banded pattern. The lesions can also be found on the stalk, leaf sheath, or ear husks. When summer weather is conducive for disease development, premature lodging due to stalk breakage may occur.



Fig. 2. Physoderma brown spot.

Fig. 2. Physoderma brown spot.

Physoderma brown spot management, but symptoms are usually not severe enough to warrant preventative fungicide applications.

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WEATHER UPDATE




Precipitation



total precipitation


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Temperature



average temperature

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THANKS FOR READING




Contact Information

Purdue Extension Entomology
901 W. State Street
West Lafayette, IN, 47907
(765) 494-8761
luck@purdue.edu
@PurdueExtEnt
PurdueEntomology

1-888-EXT-INFO

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