Pest Monitoring Monitoring target insect pests in the agricultural environment is like a tracking the communicable disease in our society. Both monitoring programs help us to develop an effective management plan and avoid unnecessary management expenses if control measures occur at the most opportune time. I am a firm believer that pro-activeness in pest monitoring programs can help crop producers implement management decisions. My pest monitoring philosophy is that early initiation leads to less expensive management options and often prevention of large pest populations. My research approach is to use/refine monitoring tools and techniques that are available in the IPM toolbox. I have been involved in developing novel monitoring techniques for new approaches. I utilize a wide variety of tools including sex pheromone lures, traps, sticky cards, and sweep net to monitor agronomical crop pests. While working in north central Montana with collaborators from the MSU-WTARC research center (Dr. Gadi VP Reddy), crop consultants (Jeff Farkell), Extension Service (Dan Picard, Tyler Lane and Kim Suta), and producers (Cory Crawford, Jody Habel, Terry Peters and Kyle Dean), we developed an effective wheat midge (spring wheat pest) monitoring program using a sex pheromone lure baited on a delta trap. Another Montana research project led us to develop sex pheromone-based monitoring tool for pea leaf weevil in field peas. With my current work in at the Oregon State University, Dr. Silvia Rondon, Daniel Ira Thompson and I have modeled the role of yellow sticky trap height on the successful monitoring of the potato hemipteran pests (potato psyllids, beet leaf-hoppers, aphids, thrips and lygus bugs) in Eastern Oregon. In collaboration with Trapview (an European company), Dr. Rondon and I are also currently using camera-mounted traps to monitor corn earworms population in corn fields.
Shrestha, G. Rijal, J. and Reddy, G.V.P. Characterization of the aggregation behavior of alfalfa weevil, Hypera postica, and its natural enemies, using geospatial models. Pest Management Science, doi: 10.1002/ps.6100
Reddy, G.V.P, *Shrestha, G., Miller, D. and Oehlschlager, A. 2018. Pheromone-Trap Monitoring System for Pea Leaf Weevil, Sitona lineatus: Effects of trap type, lure type and trap placement within fields. Insects 9, p.75.
Biological Control Program Biological control (biocontrol) involves the use of living organisms (such as predators, parasitoids, and pathogens) to minimize the population density or impact of a specific pest organism, making it less abundant or less damaging than it (Eilenberg et al. 2001). I believe biocontrol is one of the best practical options for minimizing the pest population in the agricultural crop production systems. First, biocontrol agents are target pest-specific and are easy and safe to use. Second, while compared with broad-spectrum insecticides, biocontrol agents provide environmentally sound methods of pest control. Third, the use of biological control agents helps to minimize the use of synthetic insecticides. Fourth, it can be implemented as part of an IPM. Among different types of biocontrol programs, my research interest and experiences are on augmentative and classical biocontrol programs. I am specifically interested on evaluation of biocontrol agents and how multiple factors (e.g., host stage, life-history traits, host species, persistence, and intraguild predation) influence the efficacy of biocontrol agents against target insect pests in agricultural crop environment.
Shrestha, G., Reddy, G.V.P and Jaronski, S.T. 2018. Field efficacy of Bacillus thuringiensis galleriae strain SDS-502 for the management of alfalfa weevil and its impact on Bathyplectes spp. parasitization rate. Journal of Invertebrate Pathology 153, 6-11.
Shrestha, G., Skovgård, H., Reddy, G.V., Steenberg, T. and Enkegaard, A. 2017. Role of the aphid species and their feeding locations in parasitization behavior of Aphelinus abdominalis, a parasitoid of the lettuce aphid Nasonovia ribisnigri. PLOS ONE 12, p.e0184080.
Shrestha, G., Skovgård, H., Reddy, G.V., Steenberg, T. and Enkegaard, A. 2017. Shrestha, G., Enkegaard, A., Reddy, G.V.P, Skovgård, H. and Steenberg, T. 2016. Susceptibility of larvae and pupae of the aphid parasitoid Aphelinus abdominalis (Hymenoptera: Aphelinidae) to the entomopathogenic fungus Beauveria bassiana. Annals of the Entomological Society of America, 110, 121-127.
Shrestha, G., Enkegaard, A. and Steenberg, T. 2015. Laboratory and semi-field evaluation of Beauveria bassiana (Ascomycota: Hypocreales) against the lettuce aphid, Nasonovia ribisnigri (Hemiptera: Aphididae). Biological Control 85, 37-45.
Shrestha, G., Skovgård, H., Steenberg, T. and Enkegaard, A. 2015. Preference and life history traits of Aphelinus abdominalis (Hymenoptera: Aphelinidae) when offered different development stages of the lettuce aphid Nasonovia ribisnigri (Hemiptera: Aphididae). BioControl 60, 463-471.
Shrestha, G., Skovgård, H. and Enkegaard, A. 2014. Parasitization of commercially available parasitoid species against the lettuce aphid, Nasonovia ribisnigri (Hemiptera: Aphididae). Environmental Entomology 43, 1535-1541.
Shrestha, G., and Enkegaard, A. 2013. The green lacewing, Chrysoperla carnea: preference between lettuce aphids, Nasonovia ribisnigri, and western flower thrips, Frankliniella occidentalis. Journal of Insect Science, 13(1).
Biopesticide and Synthetic Elicitor Products Evaluation Program Biopesticide and synthetic elicitor pest control products can be placed into the category of relatively safe and non-toxic products to environment and humans than traditional synthetic pesticides. Biopesticides are the pesticides derived from natural materials, such as animals, plants and microorganisms, while synthetic elicitors are chemically diverse compounds (e.g., jasmonic acid and salicylic acid) that induce plant defense response against pest and disease attack. According to United States Environmental Protection Agency, biopesticides are classified into three categories: 1) biochemicals that are derived naturally occurring substances such as plant extract ( e.g., neem oil and citrus oil) and insect pheromones, 2) microbial pesticides that contain micro-organisms as the active ingredient (e.g., a bacterium, fungus or virus), and 3) plant-incorporated protectants are pesticidial substances which plants produce from genetic material that has been incorporated to the plant (Bt cotton).Synthetic elicitor pest control technique work similar to vaccines that we use to our body against microbes (e.g., flu shot).
Shrestha, G., Mettupalli, S., Gadi, R., Miller, D. and Reddy, G.V.P. 2020. Spinosad and mixtures of an insect pathogenic fungus and pyrethrin for control of Sitona lineatus (Coleoptera: Curculionidae) in field peas. Journal of Economic Entomology, 113, 669-678.
Shrestha, G. and Reddy, G.V.P. 2019. Field efficacy of insect pathogen, botanical, and jasmonic acid for the management of wheat midge Sitodiplosis mosellana and the impact on adult parasitoid Macroglenes penetrans populations in spring wheat. Insect Science, 26, 523–535.
Shrestha, G., Briar, S.S. and Reddy, G.V.P. 2018. Plant defense elicitors: plant fitness versus wheat stem sawfly. PeerJ, 6, p.e5892.
Briar, S.S., Antwi, F., Shrestha, G., Sharma, A. and Reddy, G.V.P. 2018. Potential biopesticides for crucifer flea beetle, Phyllotreta cruciferae (Coleoptera: Chrysomelidae) management under dryland canola production in Montana. Phytoparasitica,46, 247-254.
Antwi, F.B., *Shrestha, G., Reddy, G.V.P., and Jaronski, S.T. 2018. Entomopathogens in conjunction with imidacloprid could be used to manage wireworms (Coleoptera: Elateridae) on spring wheat. The Canadian Entomologist,150, 124-139.