1. Review of Insect Problems in
Field Crops in 2013
Janet Knodel, Venkata Chapara
and Patrick Beauzay
Extension Entomology
Fall Extension Conference
October 22-25, 2013
2. Forages – Alfalfa Weevil
Increasing numbers in ND,
especially SW, SC and NC!
3. Field Damaged by Alfalfa Weevil
Reduces crop yield, crop quality, protein
content, and digestibility
Primarily on 1st cutting
Occasionally re-growth of 2nd cutting
Frosted Appearance
4. Alfalfa Weevil
Sampling – Stem Counts
• Bucket 30-stem method
• Select 30 stems from 5 sites
• Beat stems into bucket
• Determine average # of
larvae/stem (see next 2 slides)
• Determine average height of
alfalfa
Nominal Threshold (not as accurate)
IF, 30-40% damaged stems
5.
6.
7. Alfalfa Weevil IPM in ND
• Early harvest!
• Do not apply insecticide unless
weevils are at ECONOMIC
THRESHOLD levels
– Before 1st Cutting
• Calculated ET for larvae/stem from 30-stem bucket method
(or nominal threshold = 30-40% of stems damaged)
– After 1st cutting, 50% of crowns have weevil feeding
or 8 or more larvae/ft2 (6/ft2 on sandy soil); and
larvae are suppressing regrowth
• E1676 „IPM of Alfalfa Weevil in ND‟
8. Red Sunflower
Seed Weevil
Adult
•
•
•
Larva
Drop into soil to overwinter
Increasing pressures in SC, SW and NC ND
Studies with Prevathon (new sunflower insecticide) from
Dupont for control of RSSW
• Rynaxypyr® new mode of action
• Ryanodine receptor activator (IRAC Group 28)
• Active against a broad range of chewing insects
2013 data being tabulated for NSA Forum in Jan. 2014
11. Corn Borer Damage . . .
• Shot-hole damage to whorl
• Broken stalks
• Dropped ears
Greatest Yield Impact: physiological
loss from tunneling damage that stops
flow of sap, water, nutrients through
stalks (> all the above combined).
12. Corn Rootworms in Corn
Western Corn Rootworm
Diabrotica virgifera virgifera LeConte
Northern Corn Rootworm
Diabrotica barberi Smith
14. Corn Rootworm Damage
This photograph was taken near Arthur, ND in 2013!
Photo courtesy by Dr. Joel Ransom, NDSU Extension Cereals
15. Western Corn Rootworm
Diabrotica virgifera virgifera
• Gassmann et al. 2011 Field-Evolved Resistance
to Bt Maize by Western Corn Rootworm
PloS ONE 6(7): e22629
– Cry3Bb1 protein
– Iowa
– 2012 - Illinois, Minnesota, Nebraska
– Continuous corn > 3 years
– Relied on a single Bt trait for control CRW
– Increased lodging and root feeding on Bt
hybrids with CRW-resistant trait
16. North Dakota in 2012-2013
• Increasing numbers of adult
WCRWs in SE ND
• Concerned about CRW resistance
to Bt corn (not been documented in
ND yet)
• Study funded by ND Corn Council to
examine Bt-traits and efficacy
against CRWs in ND
– In collaboration with Dr. Ransom and
Dr. Boetel
17. ‘High’ Risk Corn Fields for
CRW Resistance
• Continuous corn for more
than 3 years
• Same Bt trait (e.g., Cry3Bb1)
for more than 3 years
• Lots of volunteer corn in
soybean fields (good food
source for resistant CRW)
18. CRW Trap Survey in ND
• Monitoring for adult CRWs
• Determine species and
abundance
• Pherocon AM (yellow trap)
• Scentry Multigard (green trap)
• Mid-August to September
• Results being tabulated
19. Soybean Aphid
• „Hot‟ spots in 2013, mainly eastern ND
• ND Soybean Council Study to determine „best‟
pest management strategies:
– Seed treatments (insecticides and fungicides)
– Different modes of action (OP, pyrethroid and
neonicotinoid) for foliar insecticide application
– Different timings (R1, ET of 250 aphids/plant, 100
aphids/plant)
– Rag1 aphid-resistant variety
• Results will be presented at “2014 Getting It
Right Soybean Production Meetings” at Velva,
Mohall and Wishek.
20. • 2013 Wheat
Midge Risk
forecast was for
low populations
in 2013 due in
part to drought
of 2012
• 2013 soil
samples are
being collected
for laboratory
counting of
cocoons
21. New Insect Pest Detections in 2013
• Spotted wing Drosophila (see next slide)
• Japanese Beetle
– Not detected in pheromone traps (not overwintering)
– Re-introduced again in 2013 from trucks from MN
nursery with JB-infested nursery stock
– Stark, Burleigh, Ward, Grand Forks and Cass
• Cereal Leaf Beetle
– Confirmed in 3 new counties
• Ward County at NCREC in Minot, Burke County near
Flaxton, and Renville County near Mohall
– Export concern of cereal hay to Canada and CA
22. Spotted-wing Drosophila
(fruit fly)
• First detection in CA in 2008
• Attacks healthy fruits
– Raspberries
– Strawberries
– Other soft & hard fruits
• Confirmed in ND in 2013
– 13 counties so far
– Burke, Burleigh, Cass, Cavalier, Grand Forks, Foster,
Stark, Logan, McLean, Mercer, Morton, Pembina, Stark
25. „New‟ Extension Publications
• E1676 IPM of Alfalfa Weevil in ND
• E1640 Dry Bean Grower Survey of
Production, Pest Problems and
Pesticide Use in MN and ND
• E1143 ND Field Crop Insect
Management Guide
• PP1635 Dutch Elm Disease in ND: A
New Look
• A1636 Growing Lentils in ND
• E1634 Emerald Ash Borer Biology and
IPM in ND
• E1631 IPM of Japanese Beetle in ND
27. NDSU Crop & Pest Report
• Free to subscribers with email but MUST SIGN-UP ON WEBSITE!!!
(Do not need to re-sign up if you subscribed in 2013)
• Remember to sign-up and encourage others!
– http://www.ag.ndsu.edu/cpr/
