Pest & Crop


Purdue Cooperative Extension Service


Issue 12, June , 2016 • USDA-NIFA Extension IPM Grant

Insects, Mites, and Nematodes

Agronomy Tips


Weather Update


Armyworm Pheromone Trap Report(John Obermeyer) -

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 Wk 13
Dubois/SIPAC Ag Center 0 0 348 258 11 6 22 44 35 5 9 13  
Jennings/SEPAC Ag Center 0 0 15 18 9 1 9 0 1 2 4 35  
Knox/SWPAC Ag Center 0 6 197 63 17 39 22 22 19 30 31 36  
LaPorte/Pinney Ag Center 0 25 317 296 63 149 121 29 10 42 46 79  
Lawrence/Feldun Ag Center 4 97 155 76 42 21 14 14 15 40 74 139  
Randolph/Davis Ag Center 0 0 0 24 122 162 101 14 11 29 16 70  
Tippecanoe/Meigs 0 4 141 101 45 50 55 114 32 16 58 0  
Whitley/NEPAC Ag Center 7 21 619 1,091 376 682 612 173 78 56 82 81  

Wk 1 = 3/31/16 - 4/6/16; Wk 2 = 4/7/16 - 4/13/16; Wk 3 = 4/14/16 - 4/20/16; Wk 4 = 4/21/16 - 4/27/16; Wk 5 = 4/28/16 - 5/4/16; Wk 6 = 5/5/16 - 5/11/16; Wk 7 = 5/12/16 - 5/18/16; Wk 8 = 5/19/2016 - 5/25/16; Wk 9 = 5/26/16 - 6/1/16; Wk 10 = 6/2/16 - 6/8/16; Wk 11 = 6/9/16 - 6/15/16; Wk = 6/16/16 - 6/22/16

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Corn Earworm Trap Report.
Corn Earworm Trap Report.

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VIDEOS: Yellow Striped Corn (Jim Camberato and John Obermeyer) -

Striped corn is prevalent this season. Deficiencies of several nutrients, sulfur, manganese, zinc, and magnesium, can cause striping symptoms to appear. There are subtle differences in how these deficiencies appear and often they cannot be differentiated by sight alone. Plant and soil sampling and analysis are the best tools for identifying the nutrient(s) that are deficient. If the deficiency is identified early enough, some or all of the potential reduction in yield can be overcome with additional fertilizer applied in the current growing season. Usually these deficiencies will occur in subsequent years so a clear diagnosis can allow one to modify their fertility program to avoid these deficiencies in the future. More information can be obtained at: and



Yellow Striped Corn; Diagnosis

Yellow Striped Corn; Analysis

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Damage to Corn Plants by Strong Winds (Bob Nielsen) -

Note that this was published in 2014, but that the content remains the same.

Storms packing strong winds have rolled through Indiana several time already this growing season. Recent storms, in particular, caused quite a bit of damage to the corn crop in some fields. The damage includes minor leaning or bending of plants, outright uprooting of plants (root lodging), and the so-called “green snap” phenomenon where stalks literally break off or snap above a stalk node (often below the harvestable ear).

The crop is particularly vulnerable to such damage from strong winds when it is in the latter stages of the rapid growth phase prior to pollination, wherein overall plant and root dry matter increases rapidly but more importantly, stalk internode elongation occurs very rapidly. Rapid elongation of the stalk internodes (the tissue between the stalk nodes or “joints”) often outpaces the lignification of the same tissue. The development of lignins provide the structural strength to the stalk.

Simple leaning of plants caused by strong winds.
Simple leaning of plants caused by strong winds.

Root-lodged corn with range of severity for root damage.
Root-lodged corn with range of severity for root damage.

Green snap in corn caused by strong winds.
Green snap in corn caused by strong winds.

  • Simple leaning or bending of plants caused by strong winds represents the least of the damage. Such plants should recover most, if not all, of their uprightness AND if this recovery occurs prior to pollination, there should be little effect on the success of pollination. However, if the damage occurred near the onset of pollen shed and silking, then there may be some “shading” of the exposed silks (relative to pollen capture) by the leaves and stalks of neighboring lodged plants and pollination may not occur successfully.

  • Plants that are root-lodged often recover by “goose necking” or gradually returning to uprightness, as demonstrated two years when similar strong storms caused wide areas of uprooted plants (Nielsen, 2011a, 2011b). Much like the assessment of plants that are simply leaning from wind, if the “goose necking” of rootlodged plants does not occur before the onset of pollen shed and silking, then there may be some “shading” of the exposed silks by the leaves and stalks of neighboring lodged plants and pollination may not occur successfully.

  • The likelihood that “green snapped” plants will recover is obviously low. Plants snapped off below the harvestable ear clearly represent direct loss of yield potential, but plants snapped off above the harvestable ear may yet produce grain, albeit less than desired. Because such reduction in harvestable plant population occurs so “late in the game”, there is less opportunity for compensation by neighboring plants and so the estimated yield loss will be approximately equal to the percent of green-snapped plants.

  • Related Reading

    Butzen, Steve. Brittle Snap Injury in Corn. DuPont Pioneer. [online] agronomy/library/brittle-snap/ [URL accessed July 2013].

    Nielsen, RL (Bob). 2011a. An Example of “Recovery” From Severe Root-Lodging. Corny News Network, Purdue Extension. [online] articles.11/FlatCorn-0728.html [URL accessed July 2013].

    Nielsen, RL (Bob). 2011b. Prospects of Recovery for Root-Lodged Corn. Corny News Network, Purdue Extension. [online] FlatCorn-0726.html [URL accessed July 2013].

    Thomison, Peter. 2011. Green Snap” Damage to Corn. Ohio State Extension C.O.R.N. [online] newsletters/2011/2011-23/201cgreen-snap-damage-to-corn [URL accessed July 2013].

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Weed Science Field Days – 2016 (Bill Johnson) -

The Purdue Weed Science program will be hosting Weed Science field days at 2 sites in 2016.

Our first field day, Palmer Amaranth Day, will be held on Tuesday, June 28th, at our Palmer Amaranth research site near Rensselaer, IN (the intersection on East 225 North and North 375 East, Rensselaer, IN 47978; GPS: 41° 2'39.49"N, 86°58'57.92"W). Registration will begin at 8:00 EDT. The tours will start at 8:30 and conclude at noon. Enrollment is limited to 60 people for this field day. We have applied for CCA and CCH credit. If you are interested in attending the field day at this site on June 28th, please preregister at the Purdue DTC website

The second field day, Purdue Weed Day, is scheduled for Thursday, June 30th at the Throckmorton Purdue Agricultural Center, 8343 US 231 South, Lafayette, IN 47909-9049. Registration will begin at 8:00 AM EDT, and the program will begin at 8:30. We will view the plots on the west side of highway 231 in the early part of the morning, and a waterhemp site about 1 mile east of the farm in the latter part of the morning. The Throckmorton PAC farm is located approximately 5 miles south of Lafayette on the corner of county road 800S and U.S. 231 South. For those attending the 2016 Purdue Weed Day at Throckmorton, we have applied for 3 CCH’s for category 1A. The registration form for the June 30th field day is located on the Purdue Weed Science Website at You may also call Lisa Gross at 765-494-9871.

Please register if you plan to attend. This will allow us to maintain a mailing list and to estimate coffee, doughnut, bagel, and soft drink needs for our Weed Science field days.

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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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