← All People

Julio Bernal

Bernal, Julio
Julio Bernal
Professor of Entomology
Biological Control Laboratory
Undergraduate Education
B.S. Entomology/Plant Pathology, Universidad Autónoma Chapingo, Mexico
Graduate Education
Ph.D. Entomology, University of California, Riverside
M.S. Entomology, University of California, Riverside


My research program focuses on two areas. 1) Contributing to the theory and practice of biological control of arthropod pests in managed ecosystems. Specifically, research has focused on ecology and behavior of natural enemies and pests via field and laboratory studies. And, 2) adding to our understanding of plant-defense evolution broadly and pest emergence associated with agricultural evolution, from crop domestication to changes in crop production practices.

Teaching responsibilities include classroom teaching and graduate student training. Current classroom teaching activities include Principles of Biological Control (ENTO 608), Host Plant Resistance (ENTO 610; team-taught with Soil and Crop Sciences and Plant Pathology departments), and General Entomology (ENTO 201). Courses taught previously include: Biology of Insects ENTO 313, Principles of Insect Pest Management ENTO 401, and Seminar in Entomology ENTO 681 (spring 2002).


Bernal, J.S., Medina, R.F. (2018) Agriculture sows pests: How crop domestication, host shifts, and agricultural intensification can create insect pests from herbivores. Current Opinion in Insect Science 26, 76-81, https://doi.org/10.1016/j.cois.2018.01.008.

Rojas, J.C., Kolomiets, M.V., Bernal, J.S. (2018) Nonsensical choices? Fall armyworm moths choose seemingly best or worst hosts for their larvae, but neonate larvae make their own choices. PLoS ONE 13(5): e0197628. https://doi.org/10.1371/journal.pone.0197628

Bernal, J. S., Dávila-Flores, A. M., Medina, R. F., Chen, Y. H., Harrison, K. E. and Berrier, K. A. (2017), Did maize domestication and early spread mediate the population genetics of corn leafhopper? Insect Science. doi:10.1111/1744-7917.12555

Ramirez-Romero, R., Garibay-Benítez, D., Vargas-Ponce, O., Joyce, A., Bernal, J. S. (2017) Do assortative mating and immigrant inviability help maintain population genetic structuring of an herbivore on a crop and a wild relative? Insect Science. doi:10.1111/1744-7917.12509

Chinchilla-Ramírez, M., Borrego, E.J., DeWitt, T.J., Kolomiets, M.V., Bernal, J.S. (2017), Maize seedling morphology and defence hormone profiles, but not herbivory tolerance, were mediated by domestication and modern breeding. Annals of Applied Biology, 170: 315–332. doi:10.1111/aab.12331

Maag, D., Erb, M., Bernal, J.S., Wolfender, J.-L., Turlings, T. C. J., Glauser, G. (2015) Maize Domestication and Anti-Herbivore Defences: Leaf-Specific Dynamics during Early Ontogeny of Maize and Its Wild Ancestors. PLoS ONE 10(8): e0135722. doi:10.1371/journal.pone.0135722.

Bernal, J. S., Melancon, J. E., Zhu-Salzman, K. (2015) Clear advantages for fall armyworm larvae from feeding on maize relative to its ancestor Balsas teosinte may not be reflected in their mother’s host choice Entomologia Experimentalis et Applicata, 155: 206-217, DOI: 10.1111/eea.12299.

Fiene, J., Kalns, L., Nansen, C., Bernal, J., Harris, M., Sword, G. A. (2013) Foraging on individual leaves by an intracellular feeding insect is not associated with leaf biomechanical properties or leaf orientation. PLoS ONE 8(11): e80911. doi:10.1371/journal.pone.0080911.

Dávila-Flores, A. M., DeWitt, T. J., Bernal, J. S. (2013) Facilitated by nature and agriculture: performance of a specialist herbivore improves with host-plant life history evolution, domestication, and breeding. Oecologia, DOI 10.1007/s00442-013-2728-2.

Bellota, E., Medina, R. F., Bernal, J. S. (2013) Physical leaf defenses – altered by Zea life-history evolution, domestication, and breeding – mediate oviposition preference of a specialist leafhopper. Entomologia Experimentalis et Applicata, DOI: 10.1111/eea.12122.

McLoud, LA, Bernal, J.,Vinson, S. B. (2013) Examination and revision of the larval life history of Microplitis croceipes (Hymenoptera: Braconidae). Biological Control 67, 39-43.

Takahashi, C. G., Kalns, L. L., Bernal, J. S. (2012) Plant defense against fall armyworm in micro-sympatric maize (Zea mays ssp. mays) and Balsas teosinte (Zea mays ssp. parviglumis). Entomologia Experimentalis et Applicata, 145: 191-200. DOI: 10.1111/eea.12004

Lytle, J. M., Bernal, J. S., Morse, J. G. (2012) Biology of Pseudoligosita plebeia (Hymenoptera: Trichogrammatidae), an egg parasitoid of Homalodisca spp. (Hemiptera: Cicadellidae) collected from Northwestern Mexico as a potential biocontrol agent of H. vitripennis in California. Journal of Economic Entomology, 105(5): 1532-1539. http://dx.doi.org/10.1603/EC12153

Szczepaniec, A., Widney, S. E., Bernal, J. S., Eubanks, M. D. (2012) Higher expression of induced defenses in teosintes (Zea spp.) is correlated with greater resistance to fall armyworm, Spodoptera frugiperda. Entomologia Experimentalis et Applicata, 146, 242-251. doi: 10.1111/eea.12014.

Medina, R. F., Reyna, S. M., Bernal, J. S. (2012) Population genetic structure of a specialist leafhopper on Zea: Likely anthropogenic and ecological determinants of gene flow. Entomologia Experimentalis et Applicata, 142, 223-235. DOI: 10.1111/j.1570-7458.2012.01220.x

Knutson, A. E., Butler, J., Bernal, J., Bográn, C., Campos, M. (2011). Impact of area-wide malathion on predatory arthropods and secondary pests in cotton during boll weevil eradication in Texas. Crop Protection, 30 (2011) 456e467 (doi:10.1016/j.cropro.2010.12.003).

Joyce, A. L, Bernal, J. S., Vinson, S. B., Hunt, R. E., Schulthess, F., Medina, R. F. (2010). Geographic variation in male courtship acoustics and genetic divergence of populations of the Cotesia flavipes species complex. Entomologia Experimentalis et Applicata 137, 153-164 (DOI: 10.1111/j.1570-7458.2010.01048.x).

Desneux, N., Bernal J. S. (2010). Genetically modified crops deserve greater ecotoxicological scrutiny. Ecotoxicology (2010) 19:1642–1644 (DOI 10.1007/s10646-010-0550-8).

Desneux, N., Ramírez-Romero, R., Bokonon-Ganta, A., Bernal J. S. (2010). Attraction of the parasitoid Cotesia marginiventris to host frass is affected by transgenic maize. Ecotoxicology 19, 1183–1192(DOI 10.1007/s10646-010-0502-3).

Joyce, A. L., Aluja, M., Sivinski, J., Vinson, S. B., Ramirez-Romero, R., Bernal, J. S., Guillen, L. (2010) Effect of colonization and continuous rearing on courtship acoustics of five braconid parasitoids (Hymenoptera: Braconidae), candidates for augmentative biological control of pestiferous Anastrepha (Diptera: Tephritidae) species. BioControl 55, 573-58 (DOI 10.1007/s10526-010-9278-x).

Lomelí-Flores, J. R., Barrera-Gaytán, J. F., Bernal, J. S. (2010). Impacts of weather, shade cover, and elevation on coffee leafminer Leucoptera coffeella (Lepidoptera: Lyonetiidae) population dynamics and natural enemies. Crop Protection 29, 1039-1048.

Lundgren, J. G., Gassmann, A., Bernal, J., Duan, J. J., Ruberson, J. (2009) Ecological compatibility of GM crops and biological control. Crop Protection 22, 1017-1030.

Lomeli-Flores, J. R., Barrera-Gaytan, J. F., Bernal, J. S. (2009). Impact of natural enemies on coffee leafminer Leucoptera coffeella (Lepidoptera: Lyionetiidae) population dynamics. Biological Control 51, 51-60.

Triapitsyn, S. V., Bernal, J. S. (2009). Egg parasitoids of Proconiini (Hemiptera: Cicadellidae) in northwestern Mexico, with description of a new species of Gonatocerus (Hymenoptera: Mymaridae). Journal of Insect Science, 9:05 [insectscience.org/9.05]

Joyce, A., Bernal, J. S., Vinson, S. B., Lomelí-Flores, R. (2009). Influence of adult size on mate choice in the solitary and gregarious parasitoids, Cotesia marginiventris and Cotesia flavipes. Journal of Insect Behavior 22, 12-28.

Joyce, A. L., Hunt, R. E., Bernal, J. S., Vinson, S. B. (2008). Substrate influences mating success and transmission of courtship vibrations for the parasitoid Cotesia marginiventris. Entomologia Experimentalis et Applicata, 127, 39-47

Moya-Raygoza, G., Chacón-Torres, N., Palomera-Avalos, V., Becerra-Chiron, I., Bernal, J. (2008). Effects of corn stunt spiroplasma on survival of Dalbulus maidis (Hemiptera: Cicadellidae) parasitized or predated by Gonatopus bartletti (Hymenoptera: Dryinidae) or infected by Metarhizium anisopliae (Metschn.) Sorokīn. Annals of the Entomological Society of America 101, 113-118.