western corn rootworm identification, life cycle, damage ...chapter 4: life cycle 3rdinstar of...

Western Corn Rootworm Identification, Life Cycle, Damage and Management

By:

Sammi Jo Smith

http://www.intlcorn.com/seedsiteblog/?p=434

Personal InformationLocated in Columbus

Junction, Iowa

Member of 4-H and the FFA

Raised show cattle and a miniature horse

Personal InformationFamily farm

consists of approximately 2,000 acres of corn and soybeans

Personal Information

EducationWestern Illinois University (2001-2006)

Bachelor of ScienceMajor Zoology Minor Chemistry

Iowa State University (2009-2016)Master of Agronomy

Personal Information

Author Name:

Professional Title:

Affiliation (Company / Department):

Current professional work / research interests:

Author Profile

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Sammi Jo SmithLab Analyst

Monsanto/Quality Control

I started my career at Monsanto in 2007 as a laboratory analyst. My daily duties included running chemical tests on finished products of glyphosate and analyzing data. The results of the tests indicated to the production teams whether or not the process was running correctly and that the finished products were within regulation guidelines.

Western Corn Rootworm Identification, Life Cycle,

Damage and Management

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Module Contents

Chapter 1: Introduction

Chapter 2: Identification

Chapter 3: Location and Adaptation

Chapter 4: Life Cycle

Chapter 5: Damage

Chapter 6: Management Strategies

Chapter 7: Summary

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Chapter 1: Introduction

Estimates show that over $1 billion is lost every year by American farmers due to the costs of insect management and yield loss inflicted by the WCR (America’s Farmers, 2016).

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http://albemarleplumbing.com/contact.html


Scientific classificationKingdom: Animalia

Phylum: Arthropoda

Class: Insecta

Order: Coleoptera

Family: Chrysomelidae (leaf beetle)

Genus: Diabrotica

Species: D. virgifera

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http://biology-medicine.blogspot.com/2012/09/scientific-classification-of-organisms.html


http://www.ent.iastate.edu/imagegal/coleoptera/rw/1343.20crwweggs.html

http://www.ent.iastate.edu/imagegal/coleoptera/rw/crwlarv.html

http://passel.unl.edu/pages/informationmodule.php?idinformationmodule=1029338910&topicorder=4&maxto=11


Both sexes of the adult beetle are yellow to green in color, with a black stripe down the sides of the wings

Male wing covers are often nearly entirely black while the female wings have more regular stripes

The female beetle is also distinguishable from the male because of an enlarged abdomen

Leaf beetles are among the most conspicuous beetles on plants (Clark et al., 2004)

https://www.pioneer.com/home/site/us/agronomy/crop-management/corn-insect-disease/corn-rootworm-silk-feeding/


extension.entm.purdue.eduhttp://extension.cropsciences.illinois.edu/fieldcrops/insects/western_corn_rootworm/


http://www.delange.org/Buffalo/Buffalo.htm

Buffalo Gourd, Cucurbita foetidissima, Comanche County, Kansas.


https://extension.entm.purdue.edu/wcr/images/jpg/2012/NORTHAMERICA2012.jpg


http://eap.mcgill.ca/CPAP_7.htm

Chapter 3: Location & Adaptation

http://www.myrmecos.net


https://www.pioneer.com/home/site/us/agronomy/crop-management/corn-insect-disease/corn-rootworm/


www.ent.iastate.edu/pests/rootworm


http://www.slideshare.net/jbgruver/new-root-presentation


1st and 2nd instars of development• Larvae are extremely small and soft-bodied

• Movement is accomplished via interconnected air filled pores in the soil

• Movement limited by pore size, type, texture and bulk density of the soil

• Mortality rate is high because their soft-bodies are easily punctured or scraped off during movement within coarse soils

• Larvae feed on fine root hairs and burrow into newly formed root tips


3rd instar of development• Most plant damage occurs during this stage

•Larvae feed and tunnel into the primary root system of the corn plant, including brace roots and crown, which reduces rooting depth and density

• Larvae become stronger and less prone to injury

• Growth of a body shield, composed of chitin, occurs

*Chitin: A fibrous substance consisting of polysaccharides and forming the major component in the exoskeleton of arthropods


Emergence begins from late June through early August

Male adult beetles emerge 5-7 days before the adult female beetles

Two weeks after emergence, beetles will mate and begin to lay eggs into the soil

Adult beetles feed on leaf tissue, silks, tassels and pollen

http://bugguide.net/node/view/71865/bgimage?from=24


http://www.americasfarmers.com/2015/06/08/corn-rootworms-an-overview/


https://extension.entm.purdue.edu/fieldcropsipm/insects/corn-rootworms.php

Chapter 5: Damage

https://www.extension.entm.purdue.edu/fieldcropsipm/insects/corn-rootworms.php

https://www.pioneer.com/home/site/us/agronomy/crop-management/corn-insect-disease/corn-rootworm/

Chapter 5: Damage

http://www.slideshare.net/amilavimukthiathapaththu/sink-source-relationship

Chapter 5: Damage

http://extension.cropsciences.illinois.edu/fieldcrops/insects/western_corn_rootworm/

Chapter 5: Damage

http://www.ent.iastate.edu/imagegal/plantpath/corn/rw/3936.49stalklodge.html

Chapter 5: Damage

http://www.ipm.iastate.edu/ipm/icm/2006/7-17/ http://www.ent.iastate.edu/imagegal/plantpath/corn/rw/3936.52crwinj.html

Chapter 5: Damage

http://www.ent.iastate.edu/imagegal/plantpath/corn/rw/cornrootwormroots.html

Chapter 5: Damage


Chapter 5: Damage

Rating corn root damageTo assess the level and amount of root damage inflicted by the WCR larvae, corn roots are rated according to a scale called the Node-Injury Scale. In this scale, zero represents no damage to the roots and three represents severe damage.

Chapter 5: Damage

http://www.aganytime.com/Corn/Pages/Article.aspx?article=845

Chapter 5: Damage

https://extension.entm.purdue.edu/pestcrop/2007/issue26/

Chapter 5: Damage


Chapter 5: Damage

https://www.pioneer.com/home/site/us/agronomy/crop-management/corn-insect-disease/corn-rootworm-silk-feeding/


Utilizing an integrated pest management strategy is an effective way to determine which management strategies will lead to a desired outcome•Uses economic injury levels and economic threshold levels to relate pest

damage to the dollar value of lost yield and cost to control pest•Desired outcome is to reduce levels of damage to a corn plant’s rooting

system so that the loss in yield becomes economically insignificant (Levine, et al., 2016)

*Economic injury level: The smallest number of insects (amount of injury) that will cause yield losses equal to the insect management costs. *Economic threshold: The pest density at which management action should be taken to prevent an increasing pest population from reaching the economic injury level


Three types of management strategies

Cultural• Crop scouting, employing deterrents, crop rotation and early

planting date

Chemical • Insecticides, seed treatments and repellants

Biological• Biopesticides, genetic modification and microbial insecticides


www.ent.iastate.edu

http://cfaes.osu.edu/news/articles/conference-offers-advanced-scouting-techniques-training-for-crop-advisers-and-farmers

http://crops.extension.iastate.edu/cropnews/2015/04/crop-scouting-competition-2015-open-enrollment


Crop scoutingThis graph indicates the time of year to scout for the WCR adult beetle

• Scouting from mid-May through July will assist is WCR management

http://www.brodbeckseed.com/agronomy-post/corn-and-soybean-scouting-calendars-for-insects-and-disease/


http://dtc-wsuv.org/pdunn/blackbird/


http://www.sdnotill.com/officers.htmhttp://www.hannahscupboard.com/wake-oct05-16.html


http://www.ipm.iastate.edu/ipm/icm/node/112


https://www3.epa.gov/caddis/ssr_ins_wtl.html


https://thehound2.wordpress.com


http://www.delange.org/Buffalo/Buffalo.htm


http://www.americasfarmers.com/2015/06/08/corn-rootworms-an-overview/


http://whatisbtcorn.pbworks.com

Chapter 7: Summary

http://www.intlcorn.com/seedsiteblog/?p=434

western corn rootworm identification, life cycle, damage ...chapter 4: life cycle 3rdinstar of...

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