Investigating plant health is well-rooted at UC Davis
Spring is in full bloom in Davis, and the early blossoming trees and flowers remind us of the importance of plants and the role they play in our lives. We depend on plants for the food we eat, the air we breathe, and the natural areas we enjoy. Plants are so important to our wellbeing that the United Nations designated 2020 the International Year of Plant Health. From building awareness, to encouraging government policies that protect plants, to generating more support for research at our universities, there are many ways for individuals and institutions to help foster the health and greater awareness of plants.
UC Davis is renowned for finding solutions to plant health challenges in California and throughout the world. The departments of plant pathology, plant sciences, entomology and nematology, viticulture and enology, biological and agricultural engineering, land air & water resources, and environmental science and policy all take an interdisciplinary approach to address many plant health issues. The challenges to plants are many, and new ones seem to present themselves when we least expect it. As the world becomes more interconnected, we continue to see pests and diseases spread more rapidly.
For example, citrus greening, a deadly disease that decimated groves in Florida and is threatening California, is caused by a bacterium spread by the Asian citrus psyllid, which feeds on the leaves and stems of citrus trees. It’s hard to imagine a world without fresh oranges, and this disease poses a worldwide threat. So far, citrus groves have been destroyed in Asia, Brazil and Dominican Republic. Our scientists are working with researchers to develop early detection systems and disease-resistant citrus rootstock, and engage with industry and government leaders and growers, to educate the public on how to identify diseased trees early.
In the late 1950s, UC Davis scientists partnered with USDA to establish Foundation Plant Services (FPS) to provide the agriculture industry with virus-tested grapevines and other disease-free rootstock for tree fruits and nuts. Since its establishment, strawberries, sweet potatoes and roses have been added to the list of healthy plants provided to commercial nurseries. FPS also propagates healthy plant materials for nurseries and growers throughout the United States. And last fall, UC Davis released five new grapevines that produce high-quality fruit and wine that are resistant to Pierce’s disease—a bacterium transmitted through an insect called a sharpshooter that costs grape growers millions of dollars every year in lost production and vine replacement.
The U.N. estimates that up to 40% of food crops are lost worldwide to plant pests and diseases annually, and unfortunately, the ecosystem health of our natural environment is also at risk. Sudden Oak Death first appeared in California in 1995 and has spread throughout the state’s coastal regions, rapidly killing large numbers of native oaks and other broadleaf plants. The disease is caused by the fungus Phytophthora ramorum, which is in the same genus as the pathogen that caused the Irish potato famine in the 1800s. Scientists believe this previously unknown pathogen arrived in California from Europe on ornamental rhododendrons.
Climate change also continues to pose major challenges to the plant world. In California, drought and bark-beetle infestations killed an estimated 129 million trees in the Sierra Nevada between 2012 and 2016. In response, UC Davis researchers spent two years raising 10,000 seedlings from 100 surviving sugar pine trees, and just last year, they planted this new stock for restoration efforts in the Lake Tahoe area. The hope is that this new generation of sugar pines will be stronger and better able to survive and adapt to our ever-changing environment.
This summer UC Davis will host Phyllosphere 2020, the 11th international symposium on leaf surface microbiology to a large international gathering of scientists who study the microbiome of plant leaves. I am sure it will serve to move the plant health agenda forward and produce new avenues for research and collaboration. Stay tuned for more details as this symposium draws closer, and in the meantime, take some time to enjoy the arrival of spring!