Dominic Reisig NCSU Entomology and Plant Pathology Making Smart Insecticide Choices in Soybean Proper identification Numbers at threshold Choose the correct tool Proper Identification Corn ID: 683159
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Slide1
2017 Soybean Insect Update
Dominic Reisig
NCSU Entomology and Plant PathologySlide2
Making Smart
Insecticide Choices in Soybean
Proper identification
Numbers at threshold
Choose the correct toolSlide3
Proper Identification
Corn
Earworm/Tobacco BudwormSlide4Slide5Slide6Slide7
Corn Earworm
Risky
Pyrethroid
(
Baythroid
, bifenthrin, Karate, Mustang, Tombstone)
Advantages
Cheap (unless they flare), pick up some true bugs
Disadvantages
Resistance, not effective on many armyworms,
loopers
, tobacco budworms, kill many natural enemies
Safe
Caterpillar-specific
(Blackhawk, Intrepid Edge,
Prevathon
, Steward)
Advantages
Almost always effective, some residual, preserve
beneficials
Disadvantages
Initially pricey,
w
ill not pick up true bugsSlide8
Average mean % corn earworm moth survival, 5 µg cypermethrin- 2013-2016Slide9
Untreated
Belt
Prevathon
Karate +
Prevathon
(Besiege)
Number of predators per beat sheet sample
Work done during 2013-2015 in NC and VA by VA Tech student Dr. Rebecca WhalenSlide10
I don’t understand why I have worms…I already sprayedSlide11
Do multiple defoliation events
compound to reduce yield in soybeans?
V3 Defoliation
V6
Defoliation
0
33%
66%
100%
0
100%
97%
96%
77%
33%
105%
93%
88%
83%
66%
100%
95%
101%
92%
100%
86%
75%
79%
75%
Yield (% of UTC)
B.C. Thrash, A.
Catchot
, J. Gore, F. Musser,
D
. Cook, T. Irby, J.
Krutz
- MS StateSlide12
V4 DefoliationSlide13
Effects of Soybean Planting Dateon V4 Defoliation Damage StonevilleSlide14
Delays in MaturitySlide15
Conclusions
Do reproductive thresholds need to be adjusted based on defoliation that occurred during vegetative growth stages?
Probably
not
Later planted soybeans may need a lower treatment threshold to compensate for reduced leaf area recovery time