Pest & Crop


Purdue Cooperative Extension Service


Issue 4, April 24, 2015 • USDA-NIFA Extension IPM Grant

Weather Update


Black Cutworm Moth Arrival and Larval Development– (Christian Krupke and John Obermeyer) -

  • Arriving moths are looking for egg laying sites (e.g., weedy fields, fields with extensive groud cover, etc.), and there are many to choose from.
  • Light frosts have little effect on eggs.
  • Larvae need to "grow up" before they can damage corn.
  • Accumulations of approximately 300 heat units (base 50°F) needed after egg hatch before crop damage will be noted.

Black cutworm moth catches in pheromone traps throughout the state have varied over the last week (see “Black Cutworm Adult Pheromone Trap Report”), but more importantly we know that from the previous week’s captures, significant egg-laying has occurred. Also, consider that the moths continue to arrive; that will be the case for weeks to come. That is why we continue to monitor until most corn is not only planted, but up to and including the 3-leaf stage to cover the vulnerable part of the growing season.

It is too early to scout for black cutworm. For one, very little corn has been planted in the state (1% according to Indiana Ag Statistics) and that has certainly not emerged. Secondly, the black cutworm eggs have not hatched because of the cool temperatures – egg hatch is temperature driven in this and most other insects.Light frosts (e.g., morning of April 23 and 24 in many areas) will not freeze-kill black cutworm eggs. Hatched larvae (“worms”) grow and feed anytime it is above 50°F, likely on the plant they were laid on or near, e.g., winter annual weeds. Black cutworms are generalists and feed on a wide variety of hosts. Corn is not a preferred food but larvae will switch their diet to corn as weeds are killed by herbicide application and the emerging crop is the only food. Before we can detect their presence in corn, they must develop to a size that allows them to feed on corn leaves. Refer to the following map (“Heat Units Base 50”), where we are tracking black cutworm development from the date of significant arrival (intensive capture of adults in pheromone traps), to when we expect first cutting/damage. Based on the growth development model, it takes approximately 300 heat units (50°F base) from egg hatch to early 4th instar; this is the life stage when black cutworm larvae begin to cut plants. As you can see, from April 13 (intensive captures) to April 22 (map created), 100 heat units (base 50) have accumulated in the extreme southern counties of Indiana – y’all in the south are a third of the way there! These maps will be updated and posted weekly in the Pest&Crop.

Happy Scouting!

Black cutworm moth developmentBlack cutworm larval development

Black cutworm eggsBlack cutworm eggs on leaf, next to a penny

Newly hatched black cutworm larvae feedingNewly hatched black cutworm larvae feeding on corn


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Black Cutworm Adult Pheromone Trap Report

County Cooperator BCW Trapped
Week 1 
4/9/15 - 4/15/15
Week 2 
4/16/15 - 4/22/15
Adams Kaminsky/New Era Ag 14 24*
Adams Roe/Mercer Landmark 7 40*
Allen Anderson/Syngenta Seed 2 17
Allen Gynn/Southwind Farms 1 3
Allen Kneubuhler/G&K Concepts 3 8
Bartholomew Bush/Pioneer Hybrids 0 0
Boone Campbell/Beck's Hybrids 2 7
Clay Bower/Ceres Solutions, Brazil 1 0
Clay Bower/Ceres Solutions, Bowling Green 0 0
Clinton Emanuel/Boone Co. CES 0 1
Clinton Foster/Purdue Entomology 0 4
DeKalb Hoffman/ATA Solutions 0 8
Dubois Eck/Purdue CES 27* 22*
Elkhart Kauffman/Crop Tech Inc. 24 29*
Fayette Schelle/Falmouth Farm Supply Inc. 42* 29*
Fountain Mroczkiewicz/Syngenta 2 7
Fulton Jenkins/N. Central Coop-Rochester 15 37*
Fulton Jenkins/N. Central Coop-Kewana 15 41*
Gibson Schmitz/Gibson Co. CES 0 3
Hamilton Campbell/Beck's Hybrids 10* 27*
Hamilton Truster/Reynolds Farm Equipment 1 0
Hendricks Nicholson/Nicholson Consulting 24* 76*
Henry Schelle/Falmouth Farm Supply Inc., Millville 4 7
Jasper Overstreet/Purdue CES 0 0
Jasper Ritter/Brodbeck Seeds 11 24*
Jay Boyer/Davis PAC 1 14
Jay Shrack/Ran Del Agri Services 1 3
Jay Temple/Jay County CES 1 3
Jennings Bauerle/SEPAC 5 12
Knox Bower/Ceres Solutions, Freelandville 0 0
Knox Bower/Ceres Solutions, Vincennes 4 3
Knox Bower/Ceres Solutions, Fritchton 1 0
Lake Kleine/Kleine Farms 1  
Lake Moyer/Dekalb Hybrids, Shelby 4 10
Lake Moyer/Dekalb Hybrids, Schneider 5 20
LaPorte Barry/Kingsbury Elevator 1 6
LaPorte Rocke/Agri-Mgmt Solutions  0 0
Miami Early/Pioneer Hybrids 0 2
Miami Myers/Myers Ag Service 0  
Montgomery Stine/Nicholson Sonsulting  
Newton Moyer/Dekalb Hybrids 1 9
Porter Leuck/PPAC 4 17
Putnam Nicholson/Nicholson Consulting 5 2
Randolph Boyer/DPAC 0 5
Rush Schelle/Falmouth Farm Supply Inc. 0 0
Shelby Simpson/Simpson Farms 6 6
Sullivan Bower/Ceres Solutions, Farmersburg 0 8
Sullivan Bower/Ceres Solutions, Sullivan E 14* 16*
Sullivan Bower/Ceres Solutions, Sullivan W 4 8
Tippecanoe Bower/Ceres Solutions 5 15*
Tippecanoe Nagel/Ceres Solutions 21* 37*
Tippecanoe Obermeyer/Purdue Entomology 5 10
Tippecanoe Westerfeld/Monsanto 1 9
Whitley Walker/NEPAC 29* 100*

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

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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 1                  
Jay/Davis Ag Center 0 0 2                  
Jennings/SEPAC Ag Center 0 0 0                  
Knox/SWPAC Ag Center   0 0                  
LaPorte/Pinney Ag Center 0 0 3                  
Lawrence/Feldun Ag Center 0 2 0                  
Randolph/Davis Ag Center 0 0 0                  
Tippecanoe/Meigs 0 0 1                  
Whitley/NEPAC Ag Center 0 1 5                  

Wk 1 = 4/2/15 - 4/8/15; Wk 2 = 4/9/15 - 4/15/15; Wk 3 - 4/16/15 - 4/22/15

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Total Precipitation April 15-22, 2015

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Contact Information

Purdue Extension Entomology
901 W. State Street
West Lafayette, IN, 47907
(765) 494-8761

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