Pest & Crop


Purdue Cooperative Extension Service


Issue 14, June 30, 2017 • USDA-NIFA Extension IPM Grant

Insects, Mites, and Nematodes

Weather Update


Western Bean Cutworm Moth Flight Begins Impressively (John Obermeyer) -

  • Moths have begun emerging from soil, mating and egg laying follows.
  • Scouting for egg masses should commence once moth captures are increasing daily.
  • All corn, even those with Bt-traits, should be scouted in high-risk areas.

Pheromone trapping began for western bean cutworm moths on Thursday June 22, and already several traps are catching in the hundreds, refer to “Western Bean Cutworm Adult Pheromone Trap Report.” These early, eye-popping numbers, reflect the amount of damage that occurred last season, even in Bt-traited corn. This is just the beginning of an extended moth emergence and flight, with their peak presence expected 2-3 weeks from now. Those in high-risk areas, i.e., sandy soils, high moth flight and WBC history, should be gearing up for field scouting of corn, even those with Bt-traits.

Scouting should begin once moths are being captured nightly. In five different areas of a field, inspect 20 consecutive plants for egg masses which are laid on the upper surface of the top leaves of corn and/or larvae that may have hatched and crawled to the whorl and begun to feed. Usually the newest, vertical leaf is the best place to look for egg masses. Young larvae need pollen to survive, and female moths are most attracted to cornfields that are just about to pollinate. Moths will lay eggs on whorl stage corn when pre-tassel/pollinating corn is not available. Larvae may initially be found in leaf axils, feeding on pollen that has accumulated there. Later damage from larvae, as they feed deep in the whorl (attacking the tassel to get at pollen), will resemble corn borer or fall armyworm damage. Initially the damage will be subtle and not economically important (or even noticeable). Later stage larvae enter the ear and feed on corn kernels and can cause economic damage, and also can exacerbate ear rots, including Gibberella ear rot. Stay tuned for further developments of this pest.

Western bean cutworm moth in corn whorl.

Western bean cutworm moth in corn whorl.

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VIDEO: Scouting for Western Bean Cutworm Egg Masses(John Obermeyer) -

This video shows how to properly scout for western bean cutworm egg masses in order to make treatment decisions.

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VIDEO: Western Bean Cutworm Egg Masses and Newly Hatched Larvae (John Obermeyer) -

This video shows the different color forms of western bean cutworm egg masses, where they are likely found, and the newly hatched larvae and their damage.

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Weird Insect of the Week, Silver-spotted Skipper (John Obermeyer) -

Not a year goes by that someone walking a soybean field doesn’t find these bizarre looking caterpillars for the first time. Fortunately, with today’s smartphones, they snap a picture and immediately send for identification. Yes, that scenario has already occurred just this week. It was actually more fun years ago when people would call and attempt to describe them with their vivid imaginations.

Among the many possible soybean defoliators, the silver-spotted skipper Epargyreus clarus (Cramer), certainly catches the most attention when seen. These odd-looking caterpillars, which are up to 2 inches (50 mm) in length, have brownish-red heads with two orange spots and a yellowish-green body. Larvae can often be found in leaves that have been rolled together and held by the caterpillars’ silken threads. Larvae feed on leguminous plant foliage, including black and honey locusts. Their foliage feeding is generally of minor importance, and though fearsome looking to some, the larvae will not harm you.

Adult silver-spotted skippers, which are commonly seen feeding on flowers late in the summer, have an obvious silver-white splotch on each wing. Interestingly, they avoid visiting yellow flowers, rather favoring red, blues, and pinks. Look around some flower gardens for the next couple weeks, you will see them. If you are wondering, this species can be found throughout most of the United States, although less abundant in dry climates.

Please keep sending the pictures of whatever critters you are curious about, it certainly keeps our jobs interesting. BTW, in-focus pictures really help!

Silver-spotted skipper caterpillar revealed.

Silver-spotted skipper caterpillar revealed.

Silver-spotted skipper butterfly.

Silver-spotted skipper butterfly.

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2017 Western Bean Cutworm Pheromone Trap Report(John Obermeyer) -

County Cooperator WBC Trapped
Week 1
6/22/17 - 6/28/17
Week 2 
Adams Kaminsky/New Era Ag    
Adams Roe/Mercer Landmark 0  
Allen Anderson/Syngenta Seed 0  
Allen Gynn/Southwind Farms 0  
Allen Kneubuhler/G&K Concepts    
Bartholomew Bush/Pioneer Hybrids 0  
Clay Bower/Ceres Solutions    
Clinton Emanuel/Boone Co. CES 1  
Clinton Foster/Purdue Entomology    
DeKalb Hoffman/ATA Solutions    
Dubois Eck/Purdue CES    
Elkhart Kauffman/Crop Tech Inc.    
Fayette Schelle/Falmouth Farm Supply Inc.    
Fountain Mroczkiewicz/Syngenta 41  
Fulton Jenkins/N. Central Coop/Talma 379  
Fulton Ranstead/N. Central Coop/Rochester    
Gibson Schmitz/Gibson Co. CES 0  
Hamilton Campbell/Beck's Hybrids 3  
Hendricks Nicholson/Nicholson Consulting    
Jasper Overstreet/Purdue CES 438  
Jasper Ritter/Brodbeck Seeds 302  
Jay Boyer/Davis PAC 5  
Jay Shrack/Ran Del Agri Services 0  
Jay Temple/Jay County CES/Pennville 0  
Jay Temple/Jay County CES/Redkey 3  
Jennings Bauerle/SEPAC 0  
Knox Bower/Ceres Solutions 0  
Kosciusko Bower/Ceres Solutions/Etna Green 75  
Lake Kleine/Kleine Farms 0  
Lake Moyer/Dekalb Hybrids, Shelby 157  
Lake Moyer/Dekalb Hybrids, Schneider 246  
LaPorte Rocke/Agri-Mgmt Solutions, Wanatah 120  
LaPorte Smith/Co-Alliance/LaPorte 0  
LaPorte Smith/Co-Alliance/Fish Lake 6  
LaPorte Smith/Co-Alliance/Union Mills 15  
LaPorte Smith/Co-Alliance/LaCrosse 35  
Marshall Harrell/Harrell Ag Services    
Marshall Klotz/SR 10 & SR 331 29  
Marshall Miller/North Central Coop    
Miami Early/Pioneer Hybrids 189  
Newton Moyer/Dekalb Hybrids, Lake Village 16  
Porter Leuck/PPAC 11  
Polaski Capouch/M&R Ag Services 42  
Polaski Leman/North Central Coop    
Putnam Nicholson/Nicholson Consulting 0  
Randolph Boyer/DPAC 2  
Rush Schelle/Falmouth Farm Supply Inc.    
Shelby Fisher/Shelby Co. Co-Op    
Shelby Simpson/Simpson Farms 4  
Shelby Capouch/M&R Ag Services 0  
Starke David Wickert/Wickert Consulting 5  
Starke Larry Wickert/Wickert Consulting 136  
St. Joseph Barry/Helena 3  
St. Joseph Gary Battles 1  
St. Joseph Carbiener/Union Twp. 0  
St. Joseph Smith/Co-Alliance/Granger 7  
St. Joseph Smith/Co-Alliance/New Carlisle 0  
Sullivan Bower/Ceres Solutions    
Tippecanoe Bower/Ceres Solutions    
Tippecanoe Nagel/Ceres Solutions    
Tippecanoe Obermeyer/Purdue Entomology 0  
Tippecanoe Westerfeld/Monsanto 2  
Tipton Campbell/Beck's Hybrids 0  
Vermillion Bower/Ceres Solutions    
Wabash Enyeart/North Central Coop 1  
Whitley Richards/NEPAC    

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total precipitation

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average temperature

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Contact Information

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



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