Dr. Jhalendra Rijal

Area IPM Advisor
University of California Cooperative Extension
3800 Cornucopia Way
Suite A
Modesto, CA 95358
jrijal@ucanr.edu Create VCard

Also in:
Integrated Pest Management (IPM) Statewide Program
San Joaquin County
Merced County



Dr. Jhalendra Rijal joined UCCE in 2015 as an Area Integrated Pest Management Advisor. Rijal’s interest is to work on pest monitoring, insect abundance and spatial distribution, behavioral methods of pest management-eg. mating disruption, insect behavior and chemical ecology, and application of these ecological principles into pest management to attain a sustainable production system. Rijal focuses on pest problems on major agricultural crops that includes tree nuts, tree fruits, and other specialty crops in the area.

Prior to joining UC Cooperative Extension, Rijal was a Postdoctoral Scholar in the Department of Entomology and Nematology at UC Davis. There, Rijal was working on two different collaborative research projects in peppermint and cool-season vegetable crops. The goals of these projects were to 1) understand the behavior and biology of the target pests, and 2) find the better pest management alternatives by evaluating environmentally-benign biopesticides and reduced-risk pesticides, embracing the concept of IPM. Rijal's doctoral work at Virginia Tech was related to 1) chemical ecology and food finding the behavior of larval grape root borer; 2) development of spatial-distribution based sampling plan for grape root borer in vineyard system. Rijal has received at least eight awards including 'Friends of IPM' regional award by Southern Regional IPM based on his Ph.D. work, and a national award from the President of Nepal for his outstanding performance in Master's Degree.


Ph.D. Entomology, Virginia Tech. 2014
M.S. Entomology, Tribhuvan University Nepal. 2006
B.S. Agriculture, Tribhuvan University Nepal. 2004


Entomology, insect pest management, insect mating disruption, insect spatial distribution and quantitative sampling, insect behavior and chemical ecology

Areas of Expertise (click to see all ANR academics with this expertise)


Peer Reviewed

  • Shrestha*, G., J. P. Rijal*, and G.V.P. Reddy. 2021. Characterization of the spatial distribution of alfalfa weevil, Hypera postica, and its natural enemies, using geospatial models. Journal of Pest Management. https://doi.org/10.1002/ps.6100.
    (* = equal contribution).

  • Haviland, D.R., J.P. Rijal, S. M. Rill, B. S. Higbee, C. S. Burks, and C. A. Gordon. 2021. Management of Navel Orangeworm (Lepidoptera: Pyralidae) Using Four Commercial Mating Disruption Systems in California Almonds. Journal of Economic Entomology. https://doi.org/10.1093/jee/toaa297

  • Gyawaly, S., J.P. Rijal, and S.V. Joseph. 2021. Bagrada hilaris (Bagrada bug or Painted Bug). https://www.cabi.org/isc/datasheet/8302. In: CABI Invasive Species Compendium. CAB International.

  • Gireesh, M., J.P. Rijal, and S.V. Joseph. 2021.Spatial Distribution of Hunting Billbugs (Coleoptera: Curculionidae) in Sod Farms. Insects 2021, 12(5), 402; https://doi.org/10.3390/insects12050402

  • Rijal, J. P., Joyce, A. L., and S. Gyawaly. 2021. Biology, Ecology, and Management of Hemipteran Pests in Almonds Orchard Systems in the United States. Journal of Integrated Pest Management, 12(1), 24. https://doi.org/10.1093/jipm/pmab018

  • Rijal, J.P., and F.G. Zalom. 2020. Provisional guidelines for brown marmorated stink bug control in almond. UC Statewide IPM Program Guidelines, http://ipm.ucanr.edu/PMG/r3303211.html.

  • Fisher, J.J, J. P. Rijal, and F. G. Zalom. 2020. Temperature and humidity interact to influence brown marmorated stink bug (Hemiptera: Pentatomidae), survival. Environmental Entomology. https://doi.org/10.1093/ee/nvaa146

  • Pathak, T.B., J. P. Rijal, and M. Maskey. 2020. Impact of Climate Change on Navel Orangeworm, a Major Pest of Tree Nuts in California. Science of the Total Environment. https://doi.org/10.1016/j.scitotenv.2020.142657

  • Joseph, S. V., and J. P. Rijal. 2019. Walking capacity of Lygus hesperus fifth instars in the laboratory and outdoors. Southwestern Entomologist 44(2): 403-408. https://doi.org/10.3958/059.044.0205

  • Baspinar, H., D. Doll, and J. P. Rijal. 2018. Pest management in organic almonds. In: The Handbook of pest Management in organic farming (Eds. Vincenzo Vacante and Serge Kreiter). pp. 328-347. (Full text pdf).

  • Rijal, J.P., R. Regmi, R. Ghimire, K.D. Puri, S. Gyawaly, S. Poudel. 2018. Farmers’ knowledge on pesticide safety and pest management practices: a case study of vegetable growers in Chitwan, Nepal. Agriculture. 8, 16. (Full text pdf).

  • Rijal, J. P. and L. D. Godfrey. 2018. Efficacy of selected bio-and reduced risk insecticides on mint root borer. Arth. Manag. Tests (Editor-reviewed). 43(1), 1 January 2018, tsx134. https://doi.org/10.1093/amt/tsx134.

  • Rijal, J. P., and S. Gyawaly. 2018. Characterizing brown marmorated stink bug injury in almond, a new host crop in California. Insects. 9(4), 126. https://doi.org/10.3390/insects9040126.

  • Rijal, J. P. and J. C. Bergh (2017). Grape Root Borer (Lepidoptera: Sesiidae): An Economic Pest of Commercial Vineyards in the Eastern United States. J. Integrated Pest Manag. https://doi.org/10.1093/jipm/pmx027

  • Rijal, J. P., and R. Duncan. (2017). First report of an established brown marmorated stink bug (Hemiptera:Pentatomidae) population in California agricultural crops. J. Entomol. Sci. 52(4): 450-454. (pdf)

  • Rijal, J. P., R. Wilson, and L. D. Godfrey. (2016). Characterization of spatial distribution of Tetranychus urticae in peppermint in California and implication for improving sampling plan. Exp. Appl. Acarol. 68(2): 155-171.

  • Rijal, J. P. and J. C. Bergh (2016). "Food-finding capability of grape root borer (Lepidoptera: Sesiidae) neonates in soil column bioassays." J. Entomol. Sci 51(1): 54-68.
  • Rijal, J. P., C. C. Brewster, and J. C. Bergh. (2014). Effects of biotic and abiotic factors on grape root borer (Lepidoptera: Sesiidae) infestations in commercial vineyards in Virginia. Environ. Entomol. 43: 1198-1208.

  • Rijal, J. P., C. C. Brewster, and J. C. Bergh. (2014). Spatial distribution of grape root borer (Lepidoptera: Sesiidae) infestations in Virginia vineyards and implications for sampling. Environ. Entomol. 43: 716-728.

  • Gresham, S. D., J. P. Rijal, L. C. Vieira, and J. Bova. (2014). What is the best individual solution to meeting the world’s growing energy demand? Solar energy technologies [ESA Student Debate-2012]. In: J. L. Peterson and C. Minteer (eds.). Student’s perspectives on scientific tools to solve global issues. Am. Entomol. 60: 212-222.

  • Rijal, J. P., A. Zhang, and J. C. Bergh. (2013). Behavioral response of grape root borer (Lepidopetera: Sesiidae) neonates to grape root volatiles. Environ. Entomol. 42: 1338-1347.

  • Subedi, S., Y. D. GC, R. B. Thapa, and J. P. Rijal. (2009). Rice weevil (Sitophilus oryzae L.) host preference of selected stored grains in Chitwan, Nepal. J. Inst. Agric. Anim. Sci. 30: 151-158.

  • Rijal, J. P. , and L. D. Godfrey. 2018. Efficacy of selected bio-and reduced-risk insecticides on mint root borer. Arthropod Management Tests (in press).

  • Rijal, J. P., Y. D. GC, R. B. Thapa, and L. N. Kafle. (2008). Comparative efficacy of insect pathogenic fungi (Metarhizium anisopliae and Beauveria bassiana) to Helicoverpa armigera in chickpea under field condition of Nepal. Formosan Entomol. 28: 249-258.

  • Rijal, J. P., Y. D. G.C., and R. B. Thapa. (2008). Yield loss assessment and monitoring of Helicoverpa armigera Hubner in chickpea under Chitwan condition. J. Plant Prot. Soc. Nepal. 1: 90-98.

  • Rijal, J. P., Y. D. GC, R. B. Thapa, and L. N. Kafle. (2008). Virulence of native isolates of Metarhizium anisopliae and Beauveria bassiana against Helicoverpa armigera in Nepal. Formosan Entomol. 28: 21-29.

  • Rawat, P. R., Y. D. GC, R. B. Thapa, and J. P. Rijal. (2008). Evaluation of entomopathogenic fungi with other pesticides against mustard aphid, Lipaphis erysimi (Kalt.) under field condition of Chitwan, Nepal. Proceedings of Workshop of Plant Protection Society of Nepal. 25-26 July, 2008, Kathmandu, Nepal.

  • Rijal, J. P., R. K. Malla, S. Tiwari, P. R. Rawat, and Y. D. GC. (2006). A preliminary study on the practices of insect pest management at Sukranagar VDC, Chitwan. pp 297-307. In: G. K. KC, S. Pokhrel, N. S. Upadhaya, S. P. Marahatta, B. D. Bhandari (eds.). Proceedings of a National Workshop on Integrated Pest Management. Plant Protection Society of Nepal. 25-26 August, 2006, Kathmandu, Nepal.

Non-Peer Reviewed

  • 2020

    Rijal, J. P. 2020. IPM Task at Harvest: Identifying insect pest damage through harvest sampling. The Scoop Newsletter (July). https://bit.ly/37gaaoY

    Rijal, J. P. 2020. Reports of Lilac borer infestation in commercial olive orchards in North San Joaquin Valley. UCCE Field Notes Newsletter (May). https://bit.ly/37ha7cf

    Rijal, J. P. 2020. Walnut husk fly: understanding the biology, monitoring and management of this common pest in walnut. West Coast Nut. June Issue. pp. 46-48. https://bit.ly/3mkZPys

    Rijal, J. P. 2020. How nut growers can get the best of brown marmorated stink bug. https://bit.ly/2JlMWFo.

    Rijal, J. P. 2020. Spotted wing drosophila. (Editor: Phoebe Gordon). Growing the Valley Podcast (May 12). Podcast link.

    Rijal, J. P. 2020. Managing spotted wing drosophila in blueberry and cherry orchards in California. UCCE San Joaquin Valley Tree & Vine Blog, https://bit.ly/3lfqKu6 (Apr. 16)

  • Rijal, J. P., A. Medina, R. Duncan, J. Fisher, and F. Zalom. 2019. Monitoring and abundance of brown marmorated stink bug in peach and almond orchards in the northern San Joaquin Valley. Proceedings of California Plant and Soil Conference, American Society of Agronomy-California Chapter, 5-6 February, 2019. pp 81-86. (article pdf).

  • Rijal, J.P. 2019. Increasing evidence of Pacific flatheaded borer in walnut orchards in California. West Coast Nut. November Issue. pp 28-32.

  • Rijal, J. P. 2019. Pacific flatheaded borer in walnuts. (Editor: Phoebe Gordon). Growing the Valley Podcast (December 3), podcast link.  

  • 2019

    Rijal, J. P., and S. Seybold. 2019. Pacific flatheaded borer as a resurgent pest of walnuts in California: background, questions, and future research needs. CAPCA Advisor, December, pp. 41-47.

    Rijal, J. P. 2019. Importance of Integrated Pest Management (IPM) in managing arthropod pests in organic nut production in California. Organic Farmer, Vol. 2, Issue 4. pp 44-46.

    Haviland, D.R., and P. Rijal. 2019. Mating disruption for navel orangeworm available for organic nut crops. Organic Farmer, October/November, pp 16-20.

    Rijal, J. P. 2019. Seasonal pest management task: insect monitoring in almond and walnut orchards. West Coast Nut. April Issue. pp. 10-17.

    Haviland, D., P. Rijal, E. Symmes. 2019. IPM Advisors demonstrate mating disruption for key almond pest. UC Delivers. Published: June 28, 2019. https://bit.ly/3lgF8lL

    Rijal, J. P. 2019. Insect Pest Updates (3/1, 3/23, 4/12, 4/25, 6/1, 6/15, 7/15) on the AgFax Tree Crops Updates.

    Parsons, C. and P. Rijal. 2019. Almond and pistachio growers need to be on the lookout for BMSB. West Coast Nut. February Issue. Pp 38-41.

    Rijal, J.P. 2019. California Almonds, Walnuts: Trapping Options – Quick Overview. AgFax News (March 3), https://bit.ly/39qdVe3

    Rijal, J. P. 2019. Where does the husk fly go during the winter: exploring the overwintering biology of the walnut husk fly in walnuts. CAPCA Adviser (February)

    Rijal, J. P. 2019. Invasive pests to watch out for in the vines in 2019. A special newsletter issue published for the 67th Annual Grape Day. Lodi Grape Growers and Lodi Wine Commission (February).

  • 2018

    Rijal, J. P. (2018). New Pest of Almond: The Knowns and Unknowns of Brown Marmorated Stink Bug in California. Progressive Crop Consultant (July/August).

    Martin, T., and P. Rijal. (2018). Brown marmorated stink bug moving into agriculture. The IPM Corner Blog (June).

    Rijal, J. (2018). Mating disruption and navel orangeworm. UCCE Stanislaus Walnut News (Spring).

    Rijal, J. P., and D. Haviland. (2018). Integration of mating disruption into management programs for navel orangeworm. West Coast Nut (June).

    Burks, C., E. Symmes, and J. P. Rijal. (2018). Monitoring and treatment of navel orangeworm (NOW) in walnuts: research update. Progressive Crop Consultant (March/April).

    Rijal, J. P. (2018). Insect pest monitoring for tree crops (Bloom-Spring). Field Notes Newsletter (February).

    Rijal, J. P. (2018). Brown marmorated stink bug. (Editor: Phoebe Gordon). Growing the Valley Podcast, Oct. 22. Podcast link

  • 2017

    Haviland, D., E. Symmes, J. P. Rijal, and K. Tollerup. (2017). Evaluation of the role of chlorpyrifos in almond production systems. CAPCA Adviser (December).

    Rijal, J. P. (2017). Brown marmorated stink bug becomes established in Stanislaus county orchards. 2016-Stanislaus County Crop Report. 17p.

    Rijal, J. P. (2017). Mating disruption: An effective IPM tool for navel orangeworm. Progressive Crop Consultant. Vol. 2, Issue 3 (May-June), pp. 30-34.

    Rijal, J. P. (2017). Invasion of brown marmorated stink bug (BMSB): Orchard pest update-peach growers beware. Vol. 34 (September/October, Issue 4). pp. 8-11.

    Rijal, J. P., and Duncan. (2017). Brown marmorated stink bug spread to peach growing areas in the northern San Joaquin Valley. CAPCA Newsletter (August). pp. 32-35.

    Rijal, J. P. (2017). Updates on Brown Marmorated Stink Bug (BMSB) Monitoring-2017. Field Notes Newsletter (August).

    Rijal, J. P., and R. Duncan (2017). Brown marmorated stink bug survey in cling peach orchard. The IPM Corner (March).

    Rijal, J. P. (2017). Insect pest monitoring in almonds and walnuts. The IPM Corner (March).

    Rijal, J. P., and Caprile. (2017). San Jose scale and it's biological control activity in North San Joaquin Valley. Field Notes Newsletter (February).

    Rijal, J. P. (2017). Seasonal insect pest monitoring updates in almonds. The Almond Doctor. 22 March.

    Rijal, J. P., and J. Caprile. (2017). San Jose scale and it's biological control activity in North San Joaquin Valley. Field Notes Newsletter (February).

  • McGowen, S. (2016). Safe use and handling of pesticides for commercial vegetable growers in Nepal. Editor: Rijal, J. P.

  • Rijal, J. P. (2016). Taking nut samples at harvest for insect damage evaluation. Field Notes Newsletter. August 2016

  • Rijal, J. P. (2016). IPM of Spider mites in almonds: exploring the new sampling techniques. CAPCA Adviser. August 2016.

  • Rijal, J. P. (2016). Spider mites in almonds: monitoring and management. Field Notes Newsletter. May 2016

  • Rijal, J. P. (2016). Sampling and management of spider mites in almonds. Pacific Nut Producer Newsletter Vol. 22, No. 6 (June).

  • Rijal, J. P. (2016). Research to better understand spider mite migration timing. Nuts 'n' Bolts section, Pacific Nut Producer Newsletter Vol. 22, No. 6 (June).

  • Rijal, J. P. (2016). Summary of insect monitoring in nut and fruit crops: summer update. The Scoop (of fruit and nuts in Stanislaus County). Vol 22.1 (July).

  • Rijal, J.P. (2016). "Brown Marmorated Stink Bug(BMSB)and its spread in California." Field Notes Newsletter February
  • Rijal, J.P. (2016). "Monitoring and management of San Jose scale and other insect pests during the dormant season." The Almond Doctor
  • Rijal, J. P. (2016). Spotted Wing Drosophila in California Cherries: understanding the issue and options for management. California Fresh Fruit 33(2): pp. 8-9.

  • Rijal, J. P. (2015). New IPM Advisor: introduction. Field Notes Newsletter, August-2015

  • Rijal, J. P. (2015). Obscure mealybug found on almond trees for first time in California. Entomology Today Blog, Entomol. Soc. Am. October 8. http://entomologytoday.org/2015/10/08/obscure-mealybug-found-on-almond-trees-for-first-time-in-calif
  • Rijal, J.P. (2015). "Role of Winter Sanitation for Navel Orangeworm Management." The Almond Doctor
  • Rijal, J. P. (2015). Spotted wing Drosophila in California cherries. Field Notes Newsletter-November 2015.

  • Rijal, J. P. (2012). "Out of site, out of mind: Grape root borer infestation in Virginia vineyards." The Grape Press 28(2)
  • Rijal, J. P. (2008). "Pheromone trap: An effective monitoring tool for Chickpea pod borer." SAARC AgriNews 2(1): 9p.
  • Rijal, J. P. (2006). "Pathogenic fungi combat against chickpea pod borer in Nepal." SAIC Newsletter 16(3): 7-8.

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