Issue 14, June 30, 2017 • USDA-NIFA Extension IPM Grant
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.
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This video shows how to properly scout for western bean cutworm egg masses in order to make treatment decisions.
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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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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!
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6/22/17 - 6/28/17
|Adams||Kaminsky/New Era Ag|
|Clinton||Emanuel/Boone Co. CES||1|
|Elkhart||Kauffman/Crop Tech Inc.|
|Fayette||Schelle/Falmouth Farm Supply Inc.|
|Fulton||Jenkins/N. Central Coop/Talma||379|
|Fulton||Ranstead/N. Central Coop/Rochester|
|Gibson||Schmitz/Gibson Co. CES||0|
|Jay||Shrack/Ran Del Agri Services||0|
|Jay||Temple/Jay County CES/Pennville||0|
|Jay||Temple/Jay County CES/Redkey||3|
|Kosciusko||Bower/Ceres Solutions/Etna Green||75|
|Lake||Moyer/Dekalb Hybrids, Shelby||157|
|Lake||Moyer/Dekalb Hybrids, Schneider||246|
|LaPorte||Rocke/Agri-Mgmt Solutions, Wanatah||120|
|Marshall||Harrell/Harrell Ag Services|
|Marshall||Klotz/SR 10 & SR 331||29|
|Marshall||Miller/North Central Coop|
|Newton||Moyer/Dekalb Hybrids, Lake Village||16|
|Polaski||Capouch/M&R Ag Services||42|
|Polaski||Leman/North Central Coop|
|Rush||Schelle/Falmouth Farm Supply Inc.|
|Shelby||Fisher/Shelby Co. Co-Op|
|Shelby||Capouch/M&R Ag Services||0|
|Starke||David Wickert/Wickert Consulting||5|
|Starke||Larry Wickert/Wickert Consulting||136|
|St. Joseph||Gary Battles||1|
|St. Joseph||Carbiener/Union Twp.||0|
|St. Joseph||Smith/Co-Alliance/New Carlisle||0|
|Wabash||Enyeart/North Central Coop||1|
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