Department of Entomology

Dr. Laurence D. Charlet

Adjunct Professor

USDA, ARS, Northern Crop Science Lab.
Box 5677, University Station
1307 18^th Street North
Fargo, ND 58105

Phone: (701) 239-1313
E-mail: Larry.Charlet@ars.usda.gov

Project Title:
Biologically-based control strategies for the management of sunflower insect pests.

Research focuses on the integrated pest management of insects that have emerged as pests of cultivated sunflower including the sunflower stem weevil, the banded sunflower moth, the red sunflower seed weevil, the sunflower beetle, the sunflower midge, and Lygus bug. Studies have developed an increased knowledge base on pest biology, ecology and insect-host interactions and on the use of biologically-based management strategies including biological and cultural control and host-plant resistance. Significant research outcomes include:

Sunflower beetle. The sunflower beetle is the major defoliating pest of cultivated sunflower. Studies were conducted to increase knowledge of beetle biology, overwintering habits, and determine the impact of cultivation, planting date, and biological control as pest management tactics. Results from different areas in North Dakota showed the effectiveness of delayed planting in reducing damage without affecting parasitism of the larvae.

Sunflower stem weevil. The sunflower stem weevil is a pest of cultivated sunflower that causes yield losses due to lodging of mature plants. Since the mid-1990s damage has been reported and populations have been increasing in eastern Colorado, western Kansas, and Nebraska. Research initiated to develop management strategies have included timing of chemical treatments, planting date, biological control, and plant resistance. Information has been provided on tactics to reduce damage and resistance trials have shown potential in a number of sunflower accessions as well as hybrids with lower susceptibility to attack by the weevil.

Red sunflower stem weevil. The red sunflower seed weevil is a pest of sunflower in the northern and central Plains sunflower production regions. Studies were conducted and have provided useful information on parasitoid species attacking the seed weevil and their seasonal abundance, emergence pattern of the weevil and parasitoids, distribution of weevils and parasitism within the sunflower head, and the impact of planting date as a control strategy.

Lygus bug and kernel brown spot. Kernel brown spot, observed for the first time in 1998 on dehulled confection sunflowers grown in north central United States and Canada, is unlike any previously documented insect or fungal damage. While brown spot does not directly affect yield, confection users in the food industry have set very low tolerance levels, thus elevating the consequences for what might otherwise be considered a cosmetic problem. Field, laboratory and greenhouse studies ruled out fungi as a primary causal agent and determined that the damage was the result of feeding by the tarnished plant bug. Studies are continuing to develop economic injury levels, susceptible sunflower growth stages, distribution of damage, influence of different cropping systems, and natural enemies.

Banded sunflower moth. The banded sunflower moth has consistently caused seed damage to both oilseed and confection sunflower. Detailed information was provided on the mortality, parasitization, and overwintering development through pupation of the moth and its parasitoids. Species of parasitoids from cultivated sunflower in North and South Dakota, and Minnesota were determined. Development of parasitoids in the field was determined for the major parasitoid species and revealed that they play an important role in the management of this pest. Planting date studies suggested that this tactic could be successfully used as a pest management strategy without disrupting the biological control of the banded sunflower moth.

Sunflower midge. The states of North Dakota, South Dakota, and Minnesota comprise the major U.S. sunflower region. The sunflower midge has been one of the factors limiting sunflower production. Currently, no controls are available. Research in cooperation with North Dakota State University has provided needed tools including predictive models for emergence, economic injury levels, evaluation of hybrids for resistance, and distribution patterns that aid in the management of this pest.

Integrated pest management. Insects have caused significant damage to sunflower in both the northern and central production regions of the U.S. and Canada. Information on the biology, population dynamics, and management tactics are needed by the sunflower industry and producers in their efforts to reduce crop losses. A series of publications in scientific, extension bulletins, websites, and proceedings in cooperation with university scientists have been provided as a source of current knowledge on sunflower insect pests and their control.

Charlet, L. D. 1999. The sunflower stem weevil, Cylindrocopturus adspersus, a pest of cultivated sunflower and its associated parasitoids in the central and northern plains. Abstracts 54th Meeting of the North Central Branch of the Entomological Society of America, March 28-31, 1999, Des Moines, IA, p. 47.

Miller, J. F., L. D. Charlet, and G. J. Brewer. 1999. Preliminary investigations regarding inheritance of resistance to the sunflower midge. Proc. 21st Sunflower Research Workshop, Fargo, ND, January 14-15, 1999, p. 32-35.

Kirsch, M. E., J. F. Miller, and L. D. Charlet. 1999. Effect of planting date on oleic levels of a NuSun hybrid planted at three locations in North Dakota. Proc. 21st Sunflower Research Workshop, Fargo, ND, January 14-15, 1999, p. 61-64.

Schmidt, G., G. Brewer, and L. Charlet. 1999. Comparison of two midge damage rating systems. Proc. 21st Sunflower Research Workshop, Fargo, ND, January 14-15, 1999, p. 82-87.

Charlet, L. D., J. J. Knodel, and J. D. Harbour. 1999. Impact of planting date on sunflower beetle infestation and damage at four locations in North Dakota. Proc. 21st Sunflower Research Workshop, Fargo, ND, January 14-15, 1999, p. 93-102.

Brewer, G. J. and L. D. Charlet. 1999. Introduction and overview, pp. 1-3. In. L.D. Charlet and G.J. Brewer [eds.], Biological Control of Native or Indigenous Insect Pests: Challenges, Constraints, and Potential, Thomas Say Publications in Entomology, ESA.

Charlet, L. D. 1999. Biological control of sunflower pests: searching for new parasitoids in native Helianthus - challenges, constraints, and potential, pp. 91-112. In. L.D. Charlet and G.J. Brewer [eds.], Biological Control of Native or Indigenous Insect Pests: Challenges, Constraints, and Potential, Thomas Say Publications in Entomology, ESA.

Charlet, L. D. 2000. Impact of different strategies for sunflower stem weevil management in cultivated sunflower. Abstracts 55th Meeting of the North Central Branch of the Entomological Society of America, March 26-29, 2000, Minneapolis, MN, p. 65.

Charlet, L. D. 2000. Management of the sunflower stem weevil in the central Plains. Proc. 22nd Sunflower Research Workshop, Fargo, ND, January 18-19, 2000, p. 1-9.

Tatta, V., L. D. Charlet, and G. J. Brewer. 2000. Sunflower midge predictive model for emergence and edge effect. Proc. 22nd Sunflower Research Workshop, Fargo, ND, January 18-19, 2000, p. 14-22.

Knodel, J. J., L. D. Charlet, and P. A. Glogoza. 2000. Biology and Pest Management of the Sunflower Beetle in North Dakota. NDSU Coop. Extension Service, Bulletin E-824:1-8.

Charlet, L. D. 2000. Biology and pest management strategies for the sunflower beetle in cultivated sunflower in North America. Proc. 15th ISA Conference, Toulouse, France, June 12-15, 2000, p. H22-H27.

Charlet, L. D. 2000. Sunflower midge: History, biology, and damage. Proc. 11th Great Plains Sunflower Insect Workshop, Fargo, ND, April 13-14, 2000, p. 15-21.

Tatta, V., L. D. Charlet, and G. J. Brewer. 2000. Sunflower midge: Monitoring, emergence pattern, degree-day models, edge effect, and economic injury levels. Proc. 11th Great Plains Sunflower Insect Workshop, Fargo, ND, April 13-14, 2000, p. 31-40.

Charlet, L. D. 2000. Pest management strategies for the sunflower midge: Chemical and biological control. Proc. 11th Great Plains Sunflower Insect Workshop, Fargo, ND, April 13-14, 2000, p. 41-46.

Charlet, L. D. 2001. Biology and seasonal abundance of parasitoids of the banded sunflower moth (Lepidoptera: Tortricidae) in sunflower. Biological Control 20:113-121.

Charlet, L., T. Gulya, and C. Biller. 2001. Kernel brown spot on confection sunflowers: Disease or insect induced problem? Proc. 23rd Sunflower Research Workshop, Fargo, ND, January 17-18, 2001, p. 59-62.

Tatta, V., G. J. Brewer, & L. Charlet. 2001. Predictive model for emergence of sunflower midge. Proc. 23rd Sunflower Research Workshop, Natl. Sunflower Assoc., Fargo, ND, 17-18 January 2001. p. 74-77.

Charlet, L. D., D. Olson, & P. A. Glogoza. 2002. Biological control of insect and weed pests in North Dakota Agriculture. North Dakota State Univ. Coop. Ext. Serv. Bull. E-1225. 12p.

Krupinsky, J. M., D. L. Tanaka, J. S. Fehmi, S. D. Merrill, M. A. Liebig, J. R. Hendrickson, J. D. Hanson, R. L. Anderson, D. Archer, J. Knodel, P. A. Glogoza, L. D. Charlet, S. Wright, and R. E. Ries. 2002. Crop sequence calculator, V. 2. A revised computer program to assist producers. Proc. 24^th Sunflower Research Workshop, Natl. Sunflower Assoc., Fargo, ND, 17-18 January 2002. p. 63-66.

Charlet, L. D. 2002. Insect damage in North and South Dakota sunflower fields in 2001: results from the National Sunflower Association crop survey. Proc. 24^th Sunflower Research Workshop, Natl. Sunflower Assoc., Fargo, ND, 17-18 January 2002. p. 12-19.

Charlet, L. D. 2002. Lygus bug and kernel brown spot in confection sunflower: determination of economic injury levels and susceptible growth stages, and control potential with insecticides. Proc. 24^th Sunflower Research Workshop, Natl. Sunflower Assoc., Fargo, ND, 17-18 January 2002. p. 20-29.

Gulya, T. J. and L. D. Charlet. 2002. First report of Puccinia xanthii on sunflower in North America. Plant Disease 86: 56.

Olson, D., P. Glogoza, & L. Charlet. 2002. Biological control in the urban environment: part I - predators. North Dakota State Univ. Coop. Ext. Serv. Bull. E-1228. 4p.

Olson, D. L., P. A. Glogoza, & L. D. Charlet. 2002. Biological control in the urban environment: part II - parasites and pathogens. North Dakota State Univ. Coop. Ext. Serv. Bull. E-1229. 4p.

Gulya, T. J., J. Krupinsky, M. Draper, and L. D. Charlet. 2002. First report of charcoal rot (Macrophomina phaseolina) on sunflower in North and South Dakota. Plant Disease 86: 923.

Charlet, L. D., J. S. Armstrong, and G. L. Hein. 2002. Sunflower stem weevil (Coleoptera: Curculionidae) and its larval parasitoids in the Central and Northern Plains of the USA. BioControl 47: 513-523.

Charlet, L. D. 2002. Parasitization of the red sunflower seed weevil (Coleoptera: Curculionidae) by its larval parasitoid, Triaspis aequoris (Hymenoptera: Braconidae) in cultivated sunflower. Environ. Entomol. 31: 844-851.

Charlet, L. D. 2002. Entomological challenges for sunflower as an introduced agricultural crop: review of insects pests and their management in Africa, India, and Pakistan. Proc. 2^nd International Symposium on Sunflower, Intern. Sunflower Assoc., Benoni, South Africa, 18-21 February 2002. http://isa.cetiom.fr/symposium/charletusa.htm

Projects focusing on different pest management strategies for the sunflower midge, the banded sunflower moth, red sunflower seed weevil, sunflower beetle, and Lygus bug have included the following scientists in the Department of Entomology, North Dakota State University: Gary Brewer, Phil Glogoza, Mark Boetel, Jan Knodel, and Stephen Foster.

Increasing concerns about damage caused by the sunflower stem weevil, sunflower moth, wireworms and sunflower longhorned beetle have resulted in cooperative research studies on biological, cultural, and chemical control, and host plant resistance in Colorado, Kansas, and Nebraska with the following scientists: Ron Meyer and Assefa Gebre-Amlak (Colorado State University); Rob Aiken (Kansas State University); and David Baltensperger and Gary Hein (University of Nebraska).

Pest management strategies: Evaluate efficacy of control using insecticide application based on date or degree-day models, and planting date by comparing population densities and lodging in Colorado and Kansas. The impact of the methods on a root-boring moth (Pelochrista womonana), the long-horned sunflower stem girdler (Dectes texanus) densities and parasitoids of the stem weevil will also be determined (Cooperative study with Ron Meyer and Assefa Gebre-Amlak, Colorado State University, and Rob Aiken, Kansas State University- grant funded by National Sunflower Association).

Host-plant resistance: Evaluate selected sunflower accessions and hybrids for resistance at Akron, CO. Screen perennial sunflower crosses developed by Gerald Seiler at Colby, KS. Results will be evaluated by comparing population densities and lodging (cooperative study with Rob Aiken, Kansas State University, and Gerald Seiler and Jerry Miller, USDA, ARS, Northern Crop Science Laboratory).

Biological control (parasitoids): Develop successful rearing of the parasitoid, Glypta prognatha, using lab-colonized banded sunflower moths. Study aspects of the biology of the banded sunflower moth parasitoid, Glypta prognatha, in the field and laboratory including survival, sex ratio, fecundity, host suitability, mating habits, progeny production, functional and numerical response, and behavior. Compare the parasitism of the banded sunflower moth in both wild Helianthus and cultivated sunflower and determine the impact of parasitoids in different locations in sunflower fields.

Biological control (pathogens): Field trials with new Bt isolate for efficacy against banded sunflower moth larvae in North Dakota. Evaluation based on seed damage caused by larval feeding (cooperative study with Brady Vick, USDA, ARS, Northern Crop Science Laboratory).

Host-plant resistance: Screen selected sunflower accessions and advanced lines from populations developed by Jerry Miller and Gerald Seiler in a nursery at Prosper, ND. Evaluation will be based on seed damage cause by larval feeding. Comparisons will also be made on rates of parasitism among the accessions and lines in the trial (cooperative study with Jerry Miller and Gerald Seiler, USDA, ARS, Northern Crop Science Laboratory and Gary Brewer, North Dakota State University).

Attractants: Isolation and identification of volatile chemicals from sunflower head extracts that influence host finding by female moths (cooperative study with Steve Foster, North Dakota State University- grant funded by National Sunflower Association).

Biology and Injury: Conduct investigations to evaluate the damage to confection sunflower from insect feeding by Lygus. Determine species of Lygus present, seasonal abundance, influence of adjacent crops, susceptible stage for attack, economic injury level using caged heads and variable populations, and identification of natural enemies (Cooperative project with Mark Boetel and Phil Glogoza, North Dakota State University- grant funded by National Sunflower Association).

Biological control (pathogens): Field trials with new Bt isolate for efficacy against sunflower moth larvae in Kansas. Evaluation based on seed damage caused by larval feeding (cooperative study with Brady Vick, USDA, ARS, Northern Crop Science Laboratory, Ron Meyer, Colorado State University, and Rob Aiken, Kansas State University).

Host-plant resistance: Screen selected sunflower accessions and advanced lines from populations developed by Jerry Miller and Gerald Seiler in a nursery at Colby, KS. Evaluation will be based on seed damage cause by larval feeding (cooperative study with Rob Aiken, Kansas State University and Gerald Seiler and Jerry Miller, USDA, ARS, Northern Crop Science Laboratory).

Host-plant resistance: Screen selected sunflower accessions and advanced lines from populations developed by Jerry Miller in a nursery in South Dakota. The same advanced lines will also be screened at Prosper, ND, along with perennial sunflower crosses developed by Gerald Seiler. Evaluation will be based on seed damage caused by larval feeding (cooperative study with Jerry Miller and Gerald Seiler, USDA, ARS, Northern Crop Science Laboratory, Kathy Grady, South Dakota State University, and Gary Brewer, North Dakota State University).

Assist in the insect evaluation portion of the training for individuals involved in the 2002 survey to be conducted in North and South Dakota, Minnesota, Nebraska, Kansas, Colorado, and Texas. Participate in the fall survey and conduct laboratory evaluations to determine the range and severity of brown spot injury to confection sunflower and damage from the sunflower moth, red sunflower seed weevil, and the banded sunflower moth (Grant funded by National Sunflower Association).

Parasitoids of lygus plant bugs - cooperative study investigating the crop plant range of the native braconid parasitoid, Persitenus howardi that attacks Lygus nymphs in alfalfa with Jim Barbour, Department of Entomology, University of Idaho, Parma, ID.

Biological control of sunflower insects - cooperative project searching for parasitoids in Argentina that could be used to control the sunflower moth (Homoeosoma electellum) and the sunflower beetle (Zygogramma exclamationis) using natural enemies of Homoeosoma heinrichi and H. vinciniae and Zygogramma spp. with Willie Cabrera Walsh, South American Biological Control Laboratory, USDA, ARS, Argentina.

Entomology Home
	Department of Entomology, 202 Hultz Hall North Dakota State University, Fargo ND Dr. David Rider, Interim Chair Phone: 701-231-7582	updated 09 October, 2007