Dr. Irvin joined the Hoddle laboratory in 2001 as a post doctoral scholar.  Dr Irvin has a heavy focus on researching the glassy-winged sharpshooter, Homalodisca vitripennis (Germar), and its Mymarid wasp biological control agents Gonatocerus ashmeadi, G. fasciatus, G. triguttatus, and G. tuberculifemur.

Dr. Irvin has since been promoted to Assistant Specialist and was recently awarded a Western Region Sustainable Agriculture Research and Education (Western SARE) grant to investigate the use of nectar cover crops for sustainable pest control in California vineyards.  This three-year project began in June 2007.

Dr. Irvin's current research projects include:

• Biological control of the glassy-winged sharpshooter (GWSS)

• Assessing realized lifetime parasitism of GWSS egg masses by G. ashmeadi in the field:

  • PD Symposium report 2005

  • PD Symposium report 2006

  • Poster for PD Symposium 2006

• Determining the ecological significance of brochosome deposition on GWSS egg masses

• Investigating the biology and competitive ability of a neoclassical GWSS parasitoid imported from Argentina

• Assessing the use of cover crops for sustainable pest control in Californian vineyards (funded by Western SARE)

Degrees

Bachelor of Horticultural Science with First Class Honors (1996)
     Lincoln University, New Zealand

PhD Entomology (1999)
     Lincoln University, New Zealand

Personal Profile

Dr. Irvin is a graduate of Lincoln University, New Zealand, where she completed a Bachelor of Horticultural Science and was awarded first class honors. Her honors project compared hover fly (Diptera: Syrphidae) numbers, gut fullness, female egg load and pollen preference of three New Zealand hover fly species between arable and florally-diverse habitats.  Dr Irvin showed for the first time the high dependency of New Zealand predatory hover flies on floral resources (Irvin, 1996; Irvin et al., 1999a).

Dr. Irvin went on to complete her PhD in Entomology and her thesis examined the use of understorey management for the enhancement of leafroller (Lepidoptera: Tortricidae) parasitoids (Dolichogenidea tasmanica) in apple orchards located in Canterbury, New Zealand. The results of her work (Irvin, 1999; Irvin et al., 1999b; Irvin et al., 2000; Irvin et al., 2006a) showed that sowing buckwheat, coriander, or alyssum in apple understoreys can enhance field populations of D. tasmanica and increase leafroller parasitism in the field.

In April 2001, Dr. Irvin joined the Hoddle laboratory at University of California, Riverside and has been involved in researching the biology of three Gonatocerus parasitoids associated with the biological control of glassy-winged sharpshooter (Homalodisca vitripennis), a significant pest of many agriculturally important crops in southern California. From 2001-2004 her research determined which lemon cultivar maximized H. vitripennis oviposition for use in future experiments (Irvin & Hoddle, 2004),  egg age utilization by three Gonatocerus spp. (Irvin & Hoddle, 2005a), the biological potential and competitive ability of three Gonatocerus parasitoids in the laboratory (Irvin & Hoddle, 2005b; Irvin et al., 2006b), the influence of parasitoid intraspecific competition on the sex ratio of subsequent progeny (Irvin & Hoddle, 2006), and the effect of several food resources on Gonatocerus spp. longevity (Irvin & Hoddle 2007; Irvin et al., 2007) .

During this time, Dr. Irvin also conducted research investigating the fitness costs for transgenic mosquitoes expressing the green fluorescent protein marker. The results of her work (Irvin et al., 2004) showed that survival, fecundity and longevity are significantly reduced in transgenic mosquitoes relative to the untransformed laboratory strain. This research was the first of its kind in the world and has important implications for the development and utilization of this technology for mosquito control programs, or suppression of disease transmission, which are based on genetic modification.

Currently, Dr. Irvin is building on her previous Gonatocerus work by measuring real lifetime contributions of individual female parasitoids to parasitism of H. vitripennis egg masses under field conditions, and determining the ecological significance of brochosome deposition on H. vitripennis egg masses and its effect on parasitism rates in the field.

Professional Affiliation

• Member of NZIAS (New Zealand Institute for Agricultural Science) since 1996.
• Member of New Zealand Plant Protection Society since 1997.
• Member of New Zealand Ecological Society since 1999.
• Member of New Zealand Royal Society since 1999.
• Member of Entomological Society of America since 2001.

Wratten, S. D., Gurr, G. M., Berndt, L., Irvin, N. A. (2000). Adding floral resources to agro-ecosystems: managing the consequences for third and fourth trophic levels. XXI International Congress of Entomology - XXI ICE, Brazil, August 2000.

Irvin, N. A., Hoddle, M. S. (2001). Egg age preference and "window of susceptibility" of Homalodisca coagulata eggs to attack by Gonatocerus ashmeadi and G. triguttatus.  Pierce's Disease Research Symposium, San Diego, USA, December 5 - 7, 2001.  pp. 135-136.

Berndt, L., Gurr, G. M., Wratten, S. D., Irvin, N. A. (2001). An historical analysis of habitat manipulation research. 1st International Symposium on Biological Control of Arthropods, Hawaii, USA, 17-21 September 2001.

Hoddle, M. S., Irvin, N. A. (2002).  Interspecific competition between Gonatocerus ashmeadi and G. triguttatus for glassy-winged sharpshooter egg masses.  Pierce's Disease Research Symposium, San Diego, USA, December 15 - 18, 2002. 
pp. 86-87.

Hoddle, M. S., Irvin, N. A. (2003).  Interspecific competition between Gonatocerus ashmeadi, G. triguttatus and G. fasciatus for glassy-winged sharpshooter egg masses.  Pierce's Disease Research Symposium, San Diego, USA, December 8 - 11, 2003.  pp. 251-254.

Scarratt, S. L., Wratten, S. D., Lavandero, B., Irvin, N. A. (2004). A hierarchy of research approaches to the successful use of "resource subsidies" to improve parasitoid performance. Proceedings of the IV California Conference of Biological Control, Berkeley, California, USA, 13-15 July, 2004. pp. 88-94.

Gurr, G. M., Scarratt, S. L., Wratten, S. D., Berndt, L., Irvin, N. A. (2004). Ecological engineering, habitat manipulation and pest management. In: Ecological Engineering for pest management: advances in habitat manipulation for arthropods. Gurr, G. M., Wratten, S. D, Altieri, M. A. (eds). pp. 1-12.

Irvin, N. A., Hoddle, M. S., O’Brochta, D. A., Carey, B.P., Atkinson, P. W. (2004). Assessing fitness costs for transgenic Aedes aegypti expressing the green fluorescent protein marker and transposase genes. Proceedings of the National Academy of Sciences 101 (3): 891-896.

Irvin N. A., Hoddle, M. S. (2004). Oviposition preference of Homalodisca coagulata for two Citrus limon cultivars and influence of host plant on parasitism by Gonatocerus ashmeadi and G. triguttatus (Hymenoptera: Mymaridae). Florida Entomologist 87: 504-510.

Pilkington, L. J., Irvin, N. A., Boyd, E. A., Hoddle, M. S., Triapitsyn, S. V., Carey, B. G., Morgan, D. J. W. (2004). Biological control of glassy-winged sharpshooter in California. In: Proceedings of the 4th California Conference on Biological Control, University of California, Berkeley, July 13-15, 2004. Hoddle, M. S. (ed.). pp. 133-136.

Irvin, N. A., Hoddle, M. S. (2005a).  Determination of Homalodisca coagulata (Hemiptera: Cicadellidae) egg ages suitable for oviposition by Gonatocerus ashmeadi, Gonatocerus triguttatus, and Gonatocerus fasciatus (Hymenoptera: Mymaridae).  Biological Control 32: 391-400.

Irvin, N. A., Hoddle, M. S. (2005b). The competitive ability of three mymarid egg parasitoids (Gonatocerus spp.) for glassy-winged sharpshooter (Homalodisca coagulata) eggs. Biological Control 34: 204-214.

Hoddle, M. S., Irvin, N. A. (2005). Realized life time parasitism of glassy-winged sharpshooter egg masses by Gonatocerus ashmeadi. Pierce's Disease Research Symposium, San Diego, USA, December 5-7, 2005. pp. 330-333.

Pilkington L. J., Irvin, N. A., Boyd, E. A., Hoddle, M. S., Triapitsyn, S. V., Carey, B. G., Jones, W. A., Morgan, D. J. W. (2005). Introduced parasitic wasps could control glassy-winged sharpshooter.  California Agriculture.  59 (4): 223-228

Irvin, N. A., Wratten, S. D., Frampton, C. M., Chapman, R. B., Burnip, G., Suckling, M. (2006a). The effects of apple understorey management on parasitoids of leafroller (Lepidoptera: Tortricidae) in New Zealand. Agricultural and Forest Entomology 8: 25-34.

Irvin, N. A., Hoddle, M. S., Morgan, D. J. W. (2006b). Competition between Gonatocerus ashmeadi and G. triguttatus for glassy-winged sharpshooter (Homalodisca coagulata) egg masses. Biocontrol Science and Technology 16 (4): 359-375.

Irvin, N. A., Hoddle, M. S. (2006). The effect of intraspecific compeition on progeny sex ratio in Gonatocerus spp. for Homalodisca coagulata egg masses: economic implications for mass rearing and biological control. Biological Control 39: 162-170.

Hoddle, M. S., Irvin, N. A. (2006). Realized life time parasitism of glassy-winged sharpshooter egg masses by Gonatocerus ashmeadi. Pierce's Disease Research Symposium, San Diego, USA, November 27-29, 2006. pp. 80-83.

Irvin, N. A., Hoddle, M. S., Castle. S. J. (2007). The effect of resource provisioning and sugar composition of foods on longevity of three Gonatocerus spp., egg parasitoids of Homalodisca vitripennis. Biological Control 40: 69-79.

Irvin N. A., Hoddle. M. S. (2007). Evaluation of floral resources for enhancement of fecundity and fitness of Gonatocerus ashmeadi, an egg parasitoid of the glassy-winged sharpshooter, Homalodisca vitripennis. Biological Control 40: 80-88.