- Author: Kathy Keatley Garvey
“The agricultural sector in California is so exciting, because of its diversity and economic importance,” said Nansen, whose agricultural entomology expertise encompasses seven countries including his native Denmark. “Secondly, there is a strong spirit of innovation in this region, and I hope to contribute to the development of highly advanced crop monitoring systems and decision support tools, so that farming practices can become less reliant on pesticides.”
“I also believe that the strong academic programs at UC Davis with ecology and evolution are of incredible value, and that we can integrate the basic theory from these disciplines into the fundamental of crop management to obtain more sustainable farming systems,” Nansen said. “As an example of a line of research I am interested in – application of fertilizers obviously affect crop growth, but they also affect the attractiveness of crops to many insect pests, and they influence the ability of plants to resist attacks by several important insect pests.”
“So, how can we optimize use of crop fertilizers to stimulate yields but also minimize risks of pest infestations? The answer to such a question is underpinned by in-depth understanding about host selection ecology and about fitness and evolutionary processes involved in host adaptation. In other words, it is critically important to demonstrate how we can use studies of agricultural systems to learn about the ecology of species and their food webs and evolutionary processes.”
At UC Davis, Nansen is focusing on four major themes: host plant stress detection, host selection by arthropods, pesticide performance, and use of reflectance-based imaging in a wide range of research applications.
As part of his undergraduate studies, Nansen took time off to travel to Brazil to write a book about sustainable agriculture in rainforest areas. “In this process, I learned about the potential of honey bees as both pollinators of crops but also as ‘promoters' more broadly of sustainable agricultural development,” Nansen said.
Nansen wrote his master's thesis on honey bees: “The Apis mellifera Forging Response to the Pollen Availability in Cistus salvifolius.” The plant isalso known as a sage-leaved rock rose or Gallipoli rose. He conducted field work in Portugal involving pollen identification, observations on daily flight and foraging activity, and modeling of pollen availability.
For his doctorate, his interest turned to the larger grain borer, a serious pest of stored maize and dried cassava roots. He wrote his dissertation on “The Spatial Distribution and Potential Hosts of the Larger Grain Borer, Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae), in a forest in Benin, West Africa.” His research involved stored product insect ecology, field trapping with pheromone traps, experimental work on pheromone production, vegetation analysis, satellite image interpretation, laboratory infestation of potential breeding substrates, and histological studies.
“Agricultural entomology has given me so many opportunities to travel and work internationally, and that has been extremely rewarding,” he said. “I am passionate about food production and how to produce food ‘smartly' – so that it is profitable and also environmentally sustainable. And insects are critically important in manipulated food webs, such as, a crop field, forest, orchard, or horticultural greenhouse. I enjoy studying their ecological roles in these systems and how we can use that information to develop smarter ways to produce food.”
Nansen recalled that his childhood exposures to international scientists played a major role in his choice of a career. His father, a professor in veterinary parasitology, entertained many colleagues in the family home. “And my mother cooked the food! This is probably the main reasons why I enjoy both cooking and why my career has been so international.”
“Even though Denmark is a very small country (5 million people),” Nansen said, “it has been at the forefront of agricultural research and production for many decades. And growing up, my father took me on field trips and exposed me to farming systems.” In fact, young Christian earned his weekly allowance in the chicken business: he sold eggs to neighbors.
Nansen said he is delighted to see a “steadily growing appreciation for the origin and quality of the food we eat. Today, in the 21st century, the technologies deployed in modern agriculture are so advanced and similar to the cutting-edge technologies in other fields, he said. “Those technologies require skill sets beyond what most people may be aware of. Use of drones, remote sensing, GIS models, mathematical models of weather, crop physiology and soil dynamics, models to optimize input requirements and minimize economic risks, phone apps to optimize applications of agro-chemicals – these are all skill sets and approaches we are using as part of studying food production systems and developing innovative and reliable tools to be used within the agricultural sector.”
Nansen previously held faculty positions at Texas A&M, Texas Tech, and most recently at the University of Western Australia. As a university employee, the most common way to “create impact” is by influencing the minds and interests of students, but also of particular stakeholders,” he said.
“While working in Texas, we developed a very effective sampling method for an important insect pest in potato fields, and a 4th generation potato grower (Bruce Barrett) actually changed his management strategy because of our sampling method: he purchased the equipment needed and hired people specifically to conduct insect sampling, as he saw how use of this method could save him thousands of dollars on insecticide sprays--because he would now have a much better idea about when and where to spray. Recently, in Australia we demonstrated to farmers that sub-optimal maintenance of their stored seed grain led to loss of crop vigor and therefore a loss in crop yields. That is, if the seed grain is poorly managed, then stored grain infestations will likely occur, and these beetles will damage the kernels so they don't germinate. We provided simple guidelines for how the grain storage practices could be improved, so quite a few farmers are now following our guidelines to optimize the vigor of their seed grain.”
“Sometimes, we can go further and actually develop tools or gadgets which end-users may find useful. As an example, we have developed a freely available phone app to optimize pesticide spray applications based on weather and spray settings (http://agspsrap31.agric.wa.gov.au/snapcard/). The main goal with this phone app is to guide farmers so that they obtain the best possible spray coverage--to reduce risk of pests developing resistance--and to encourage them NOT to spray pesticides under unfavorable conditions.”